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  • Organic Chemistry  (2,010)
  • 1980-1984  (2,010)
  • 1925-1929
  • 1984  (646)
  • 1982  (695)
  • 1980  (669)
Collection
Keywords
Publisher
Years
  • 1980-1984  (2,010)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Synthetic routes to trace constituents of algal pheromone bouqets and other information-imitating substances (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 616-624 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structural modifications of multifidene (1), viridiene (2) and ectocarpene (5) led to the synthesis of eleven new pheromone components or imitatin substances mostly by Grignard alkylation of cyclopentene and cycloheptadiene synthons. A new lactone α,ω dienol conversion is reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670230
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  • 2
    Electronic Resource
    Electronic Resource
    Photoelectron-Spectroscopic Characterization of 3,4-Dimethyl-2,4-hexadienes (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 640-653 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The He(Ia) photoelectron (PE) spectra of the (E,E)-, (E,Z)- and (Z,Z)-isomers of the title compound have been recorded to obtain information about their conformation in the gas phase. For a valid correlation with the PE data of other dienes it is necessary to take the potentials V(ϕ) for internal rotation and the corresponding conformer population densities P (ϕ) into account, as well as the rather complicated way wy in which the π-1 ionization energy gap ΔI(ϕ) depends on the direct π-orbital interaction and the long-range ‘through-space’ interaction between the semi-localized methyl-group orbitals and the π-orbitals. These factors being taken into account, the mean twist angles, ϕ, compatible with the PE-spectroscopic results are ϕ (E,E) ≍ O° ± 30°, ϕ (E,Z) ≍ 80° or 110° within ± 15°, and ϕ (Z,Z) ≍ 85° to 105°. These results are in rough agreement with electron diffraction data by Traetteberg [15], other spectroscopic results and, for the (E, E)- and (Z,Z)-isomers, internal rotation potentials V(ϕ) previously calculated by Roth [17]. On the other hand the potential V (ϕ) proposed for the (E,Z)-isomer does not seem to be compatible with our findings.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670303
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  • 3
    Electronic Resource
    Electronic Resource
    Cob(I)alamin Differentiating Alkenes During Saturation11th Communication in the series ‘Cob(I)alamin as Catalyst’; for the 10th communication see [1a]. (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 669-683 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The olefins 2, 7, 11, and 19, have been reduced using catalytic amounts of cob(I)alamin(I(I)). During a slow saturation, the catalyst is able to differentiate the two diastereotopic faces of the endocyclic double bonds in 11 (t1/2 4 h,. cf. Scheme 3) are reduced much faster. A rationalization of the data can be obtained formulating tertiary alkylcobalamins as intermediates. Of the oxime 6 (cf. Scheme 2) and the p- bromobenzoate 23 (cf. Scheme 5) the structures have been determined by X-ray analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670306
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  • 4
    Electronic Resource
    Electronic Resource
    Stoffwechselprodukte von Mikroorganismen 226. Mitteilung225. Mitteilung s. [1]. Versuche zur Strukturaufklärung von Niphimycin, 3. Teil. Identität von Scopafungin mit Niphimycin I und Lage des Malonylrestes in Niphimycin und CopiamycinHerrn Dr. Arnold Brossi, Bethesda, Md., zum 60. Geburtstag gewidmet (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 696-705 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structural Elucidation of Niphimycin, Part 3. Identity of Scopafungin and Niphimycin I. Position of the Malonyl Residue of Niphimycin and CopiamycinThe identity of scopafungin with niphimycin I was proven by spectroscopic and chromatographic methods and by common degradation products. The position of the malonyl residue in niphimycin I (9) and in copiamycin (14) was deduced by 1H-NMR spin-decoupling experiments of a degradation product (10).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670309
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesen, chemische und elektrische Eigenschaften von Tetrathiafulvalen mit 1,6-Methano[10]annulen-Partialstruktur und von Chalcogendiimid-derivatenFrau Prof. Dr. Dr. E.h. M. Becke-Goehring, Heidelberg, mit herzlichen Wünschen zum 70. Geburtstag gewidmet (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 574-582 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses, Chemical and Electrical Properties of Tetrathiafulvalene with a 1,6-Methano[10]annulene Moiety and of Chalcogendiimide-DerivativesThe synthesis of the tetrathiafulvalene 6 has been described: the reaction of 1 with the benzenedithoil 2 yielded the bis-dithioacetal 3 of 1,6-methano[10]annulene-dicarbaldehyde 1. The oxidation of 3 in the presence of HBF4 in Et2O yielded the salt 4, elimination of a hydride anion with triphenylmethylium tetrafluoroborate the salt 5, and elimination of a proton in 5 with Et3N the tetrathiafulvalene 6 with a 1,6-methano[10]annulene moiety. The spectroscopic and electrochemical properties of 6 are described, and also the syntheses and properties of charge-trasnfer complexes 7 and 8, including the properties of electric conductivity of 7 and 8. the syntheses of 9-13 are reported and also their spectroscopic properties.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670225
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  • 6
    Electronic Resource
    Electronic Resource
    Voltammetrische Untersuchungen der Oxydation der symmetrischen Triazacarbocyanine in Acetonitril (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 765-769 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Voltammetric Investigations on the Oxidation Step of Symmetrical Triazacarbocyanine Dyes in Acetonitrile SolutionThe oxidation behaviour of twelve symmetrical triazacarbocyanine dyes with different heterocycles in MeCN (containing tetrabutylammonium perchlorate) has been investigated by means of dc-, ac- and cyclic triangular wave voltammetry. The oxidation mechanism has been found to be of the type ec, with the electrochemical step being reversible to irreversible. Oxidation potentials and transfer coefficients have been measured (E1/2 1.60 to 2.12 V vs. Ag/AgCl) and compared with known properties of carbocyanines. The effect of substituents X has been studied on the compounds 1,3-diethyl-2-[3-(1,3-diethyl-5-X-benzimidazolin-2-ylidene)-1-triazeno]-5-X-benzimidazolium tetrafluoroborate ((1a(X)) and 3-ethyl-2-[3-ethyl-5-X-Δ4-1,3-thiazolin-2-ylidene)-1-triazeno]-5-X-1,3-thiazolium tetrafluoroborate (1g(X)), and ρ-values of 0.425 and 0.565 V, respectively, have been found.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670317
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  • 7
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    Electronic Resource
    Enantioselective synthesis of (+)- and (-)-cis-2-methyl-4-propyl-1,3-oxathiane and their olfactive properties (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 947-952 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantioselective synthesis of (+)- and (-)-cis-2-methyl-4-propyl-1,3-oxathine 8 and 9 form (E)-2-hezen-1-ol (1) as common starting material is described. The two enantiomeric forms exhibit different organoleptic properties.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670405
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  • 8
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    Electronic Resource
    Plectranthone A, B, C und D. Diterpenoide Phenanthren-1,4-dione aus Blattdrüsen einer Plectranthuus sp. (Labiatae) (1984)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 1003-1011 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plectranthons A, B, C, and D. Diterpenoid Phenanthrene-1,4-diones from Leaf-glands a Plectranthus sp. (Labiatae)The following structures of four new 1,4-phenanthraquionones, isolated in minute amounts from the coloured leaf-glands of a Plectranthus sp. obtained from the borders of Lake Kiwu2, Rwanda, are proposed: plectranthon A (1; 3-hydroxy-5, 7,8-trimethyl-2-(2-propenyl)phenanthrene-1, 4-dione), plectranthon B (2; 2-(2ξ-acetoxypropyl)-3-hydroxy-5,7,8-trimethylphenanthrene-1,4-dione), plextranthon C (3; 3-hydroxy- 7,8-diemethyl-2-(2-propenyl)phenanthrene-1,4-dione), and plectranthon D (4; 3-hydroxy-7,8,10-trimethyl-2-(2-propenyl)phenanthrene-1,4-dione). 2-(2ξ-Hydroxypropyl)-3,6-dihydroxy-5,7,8-trimethylphenanthrene-1,4-dione (11), a compound very similar to 1-4, was prepared by a Wagner-Meerwein, rearrangement of coleon E (5). Biogenetically, the plectranthons are derived from abietanoic precursors. The compounds 1, 2 and 4 are the first natural C20-phenanthrenes of diterpenoid origin.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19840670412
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  • 9
    Electronic Resource
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    Di- und Polyaminozucker, XXVIII1) Zur Substitution von 2-Amino-2-desoxy-α-D-glucopyranosiden in der 3-Stellung (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 265-274 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Di- and Polyamino Sugars, XXVIII1). - Substitution Reactions of 2-Amino-2-deoxy-α-D-gluco-pyranosides at Position 3Nucleophilic substitutions of N-protected 2-amino-2-deoxy-3-O-mesyl-α-D-glucopyranosides with azide ions were severely restricted by neighboring group participations. N-acetyl as blocking group (2) led to the formation of the oxazoline 3 while from N-dinitrophenyl derivatives (9; 17) isomeric products (10, 11; 18, 19) were formed via epimines. Structure proofs were given by spectroscopy as well as by independent syntheses.
    Notes: Nucleophile Substitutionen an N-geschützten 2-Amino-2-desoxy-3-O-mesyl-α-D-glucopyranosiden mit Azid-Ionen wurden durch Nachbargruppenreaktionen behindert. N-Acetyl als Schutz-gruppe (2) führte zum Oxazolin 3, aus Dinitrophenyl-Derivaten (9; 17) wurden über Epimine isomere Produkte (10, 11; 18, 19) erhalten. Die Konstitutionsbeweise wurden sowohl anhand der Spektren als auch durch unabhängige Synthesen geführt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820210
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  • 10
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    Sulfosilylierung von Aromaten mit Chlorsulfonsäure-trimethylsilylester (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 282-297 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfosilylation of Aromatic Hydrocarbons by Trimethylsilyl ChlorosulfonateAromatic hydrocarbons 2, 6, 8, 9, 13, 16, 18, 19, 22 react with trimethylsilyl chlorosulfonate (1) to give trimethylsilyl arenesulfonates 5, 7, 11, 12, 15, 23 or sulfonic acids 17, 20, 21. If trimethylsilyl sulfonates are obtained, working up of the sulfonation mixtures is possible by distillation. By hydrohalogenolysis of trimethylsilyl sulfonates 5 at 0-5°C anhydrous sulfonic acids 3 result. The pathways to diphenylsulfone (25a) in the reaction of benzene (2a) with 1 were investigated. In this connection we succeeded in synthesizing benzenepyrosulfonic acid (28) and trimethylsilyl benzenepyrosulfonate (29).
    Notes: Durch Umsetzung der Aromaten 2, 6, 8, 9, 13, 16, 18, 19, 22 mit Chlorsulfonsäure-trimethylsilylester (1) erhält man die Arensulfonsäure-trimethylsilylester 5, 7, 11, 12, 15, 23 bzw. Sulfonsäuren 17, 20, 21. Die Aufarbeitung der Sulfonierungsgemische erfolgt, wenn Silylester entstehen, destillativ. Aus der Hydrohalogenolyse der Trimethylsilylester 5 bei 0-5°C resultieren die wasserfreien Sulfonsäuren 3. Am Beispiel der Reaktion von Benzol (2a) mit 1 werden die Möglichkeiten der Bildung von Diphenylsulfon (25a) untersucht. In diesem Zusammenhang gelang die Synthese von Benzolpyrosulfonsäure (28) und Benzolpyrosulfonsäure-trimethylsilylester (29).
    Additional Material: 11 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820212
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  • 11
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    Zur Struktur eines neuen Nortriterpens aus den Bulbi von Scilla scilloides Druce1) (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 306-314 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of a New Nortriterpene from the Bulbs of Scilla scilloides Druce1)From the acetone extract of the bulbs of Scilla scilloides Druce (Liliaceae) the new nortriterpene 1 has been isolated. The structure of 1 was established on the basis of chemical and spectral evidences. Besides the free state 1 was obtained by mild acid hydrolysis of the acetone-insoluble and methanol-soluble fraction suggesting the existence of 1 also in the form of its glycosides.
    Notes: Aus dem Acetonextrakt der Bulbi von Scilla scilloides Druce (Liliaceae) wurde das neue Nortriterpen 1 isoliert. Auf Grund der chemischen und spektroskopischen Untersuchungen ließ sich die Struktur von 1 ermitteln. Neben dem frei enthaltenen 1 wurde offenbar glycosidisch gebundenes 1 bei der milden Säurehydrolyse der in Aceton unlöslichen und in Methanol löslichen Fraktion erhalten.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820214
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  • 12
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    Regioselektive Synthese der N-Monomethyl-Derivate des 7-Desazahypoxanthins (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 805-812 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselective Synthesis of the N-Monomethyl Derivatives of 7-DeazahypoxanthineMethylation of 3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one (1a) or its 2-methylthio derivative with dimethyl sulfate in alkaline solution leads preferentially to the 3-methyl derivatives 2a or 2b, respectively. The N-1 isomer 3, however, is obtained by condensation of ethyl 2-cyano-4,4-diethoxybutyrate with N-(methyl)thiourea via the pyrimidine 4a which after cyclisation to 5a was desulfurised to 3. Phase-transfer methylation of 4-methoxy-2-methylthio-7H-pyrrolo[2,3-d] pyrimidine furnishes 8a which after ether cleavage and desulfurisation gave the N-7-methyl isomer 8c.
    Notes: Die Methylierung von 3,7-Dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-on (1a) oder seines 2-Methylthioderivates mit Dimethylsulfat führt im alkalischen Medium bevorzugt zu den N-3-Methyl-Derivaten 2a bzw. 2b. Das N-Isomer 3 wird hingegen durch Kondensation von 2-Cyan-4,4-diethoxybuttersäure-ethylester mit N-(Methyl)thioharnstoff über das Pyrimidinderivat 4a durch Cyclisierung zu 5a und anschließende Desulfurierung erhalten. Phasentransfer-Methylierung von 4-Methoxy-2-methylthio-7H-pyrrolo[2,3-d]pyrimidin führt zu 8a, aus dem durch Etherspaltung und Entschwefelung das N-7-Methylisomer 8c entsteht.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820421
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  • 13
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    A Short Synthesis of Muscimol (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 817-820 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eine kurze Synthese von MuscimolMuscimol (1) wurde, ausgehend von Acetylendicarbonsäure-dimethylester (3) und N-Hydroxyharnstoff, in 3 Schritten mit 30proz. Ausbeute synthetisiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820423
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  • 14
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    Zur Addition von CH-aciden Verbindungen an die CC-Dreifachbindung (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 989-993 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Contribution to the Addition of CH-acidic Compounds to the CC Triple BondIn an addition-isomerisation reaction α-alkyl- and α-arylbenzylcyanides 1 add phase-transfer catalysed to 1-propargylazoles 2 yielding substituted 4-azolyl-3-methyl-3-butenenitriles 3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820519
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  • 15
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    Massenspektrometrische Untersuchung langkettiger Alkatriene Nachweis eines strukturspezifischen Dienfragmentes (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1001-1005 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass Spectrometric Analysis of Long-chain Alkatrienes  -  Evidence of a Structure Specific Diene FragmentEI mass spectra of 1,n,(n + 2)-alkatrienes show structure specific fragments which allow the determination of the double bond position.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820521
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  • 16
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    Vicarious Nucleophilic Substitution of Hydrogen in Nitropyridines by α-Chloroalkyl Phenyl Sulfone Carbanions (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 8-14 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stellvertretende nucleophile Substitution von Wasserstoff in Nitropyridinen durch α-Chloralkylphenylsulfon-CarbanionenNitropyridine und Chlornitropyridine reagieren mit Carbanionen von α-Chloralkylphenylsulfonen unter „stellvertretender nucleophiler Substitution“ von Wasserstoff in o- und p-Stellung zur Nitrogruppe. Als allgemeine Regel wurde beobachtet, daß die „stellvertretende Substitution“ des Wasserstoffs rascher als die nucleophile Substitution von entsprechend aktiviertem Halogen erfolgt. Die Orientierung der Wasserstoff-Substitution wird diskutiert.
    Notes: Nitropyridines and chloronitropyridines react with carbanions of α-chloroalkyl phenyl sulfones yielding products of the vicarious nucleophilic substitution of hydrogen at positions ortho and para to the nitro group. A general rule that the vicarious substitution of hydrogen proceeds faster than the nucleophilic substitution of equally activated halogen is observed. The orientation of the hydrogen substitution is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419840103
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  • 17
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    Masthead (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982) 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820101
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  • 18
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    Stoffwechselprodukte von Mikroorganismen, 2041) Die Struktur von Imacidin C (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 28-40 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metabolic Products of Microorganisms, 2041) - The Structure of Imacidin CImacidin C, the main peptide antibiotic from Streptomyces olivaceus, has been identified as (R)-β-hydroxyisotridecanoic decapeptide lactone 5. This paper describes the analysis of its lactone linkage and amino acid sequence by chemical degradation and partial hydrolysis. The amino acid configuration was determinated enzymatically and by gas chromatography on chiral phase.
    Notes: Imacidin C, der Hauptbestandteil einer Gruppe chemisch ähnlicher Peptidantibiotica aus Streptomyces olivaceus, wurde als (R)-β-Hydroxyisotridecanoyl-decapeptidlacton 5 identifiziert. Aminosäuresequenz und Größe des Lactonringes wurden durch Partialhydrolyse und Abbaureaktionen ermittelt, die Konfiguration der Aminosäuren enzymatisch und durch Gaschromatographie an chiraler Phase bestimmt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820104
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  • 19
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    Carbonyl and Thiocarbonyl Compounds: Reactions of 4-Chloroxanthione with Diazoalkanes and Compounds containing Active Hydrogen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 191-195 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonyl und Thiocarbonylverbindungen: Reaktionen von 4-Chlorxanthion mit Diazoalkanen und Ch-aciden verbindungenWährend 4-Chlorxanthion 1 mit Diazomethan das Dithiolan 2 ergibt, entstehen mit anderen Diazoalkanen die Episulfide 3-5, deren Entschwefelung zu den entsprechenden Ethylenen 6-7 führt. Malononitril und Cyanessigsäure-ethylester reagieren mit 1 zu den Cyanderivaten 8a, b. Mit Hydrazinen und p-Toluidin ergibt 4-Chlorxanthion (1) die Hydrazone 9a, b und die Schiff-Base 9c. In Abhängigkeit von den Reaktionsbedingungen liefert die Oxidation des Hydrazons 9a die Diazoverbindung 10 oder das Ketazin 11. Hydroxylamin reagiert mit 1 zum Oxim 9d, das mit Phenylisocynat zum N-Phenylcarbamat 9e reagiert.
    Notes: While 4-chloroxanthione 1 gives with diazomethane the dithiol 2, it reacts with other diazoalkanes to give the episulfides 3-5, desulfurization of which forms the ethylenes 6 and 7. Malononitrile and ethyl cyanoacetate react with 1 to give the cyano derivatives 8a, b. With hydrazines and p-toluidine, 4-chloroxanthione (1) give the hydrazones 9a, b and the Schiff's base 9c, respectively. The hydrazone 9a on oxidation may give either the corresponding diazo compound 10 or the ketazine 11 according to the reaction conditions. The title compound 1 reacts with hydroxylamine to yield the oxime 9d which forms the N-phenylcarbamate 9e when treated with phenyl isocyanate.
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    Reactions of 4-Chloro-9H-xanthene-9-thione with Tetrachloro-o-benzoquinone (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 196-198 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaktionen von 4-Chlor-9H-xanthen-9-thion mit Tetrachlor-O-benzochinon4-Chlor-9H-xanthen-9-thion (1) reagiert mit Tetrachlor-o-benzochinon zu dem cyclischen Acetal 2. Zur Struktursicherung wurde 2 auf unabhängigen Wegen aus Tetrachlor-o-benzochinon und 4-Chlor-9-diazo-9H-xanthen oder 4-Chlor-9H-xanthen-9-on-hydrazon sowie aus Tetrachlorbrenzcatechin und 4,9,9-Trichlor-9H-xanthen synthetisiert. Die Spaltung der Acetalgruppe in 2 mit Salzsäure, Malononitril, Cyanessigsäure-ethylester und Hydrazinhydrat wurde studiert.
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  • 21
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    Polyhydroxyamine via Diensynthese mit Nitrosoverbindungen, IX. trans-6-Azido-1,3-cyclohexadien-5-ol als Edukt bei der Synthese von Kondurdiamin- und Streptaminisomeren (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 203-212 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyhydroxyamino Compounds via Diene Synthesis with Nitroso compounds, IX.  -  trans-6-Azido-1,3-cyclohexadien-5-ol as educt for the Synthesis of Kondurodiamine and Streptamine IsomersThe diaminodideoxykonduritols 8a, 8b, and 9 as well as the analogs 10 and 11 of Streptamine have been synthesized starting with O,N-5,6-disubstituted cyclohexadienes.
    Notes: Die Diaminodidesoxykondurite 8a, 8b und 9 sowie die Streptaminanalogen 10 und 11 werden ausgehend von O,N-5,6-disubstituierten Cyclohexadienen synthetisiert.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198419840202
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  • 22
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    Lichtinduzierte Reaktionen an Morphinderivaten, 31) Photo-Beckmann-Umlagerung 2. Art (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 112-117 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Light-induced Reactions of Morphine Derivatives, 31) - 2nd Order Photo Beckmann RearrangementIrradiation of the oxime 1b leads to a fragmentation reaction, called second-order photo Beckmann rearrangement. A C-C bond is splitted with formation of a triple CN bond and a methoxy, ethoxy, or hydroxy group is introduced. On heating with acid, the nitriles 3a, b and 7a are transformed into the lactam 6.
    Notes: Die Bestrahlung des Oxims 1b führt zu einer als Beckmann-Reaktion 2. Art bezeichneten Fragmentierungsreaktion. Unter C-C-Bindungsspaltung kommt es zur Ausbildung einer CN-Dreifachbindung und zur Einführung einer Methoxy-, Ethoxy- oder Hydroxy-Gruppe. Beim Erhitzen mit Säure werden die Nitrile 3a, b und 7a in das Lactam 6 umgewandelt.
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    URL: http://dx.doi.org/10.1002/jlac.198219820112
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  • 23
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    Ein neuartiges dimeres Corrinoid mit Bisallyl-Struktur (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 118-120 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Novel Dimeric Corrinoid with Bisallyl StructureOn thermolysis of heptamethyl dicyanocobyrinate (in decalin at 190°C), a dimer is formed (among other products) which according to its 13C and 1H-NMR data and its molecular mass possesses the structure of tetracyanobis(7-decarboxymethyl-7,8-didehydro-5-methylene-5-norcobyrinic acid) dodecamethyl ester (2).
    Notes: Bei der Thermolyse von Dicyanocobyrinsäure-heptamethylester (in Decalin bei 190°C) bildet sich u. a. ein Dimeres, dessen Konstitution sich aufgrund von 13C- und 1H-NMR-Daten sowie der Molmasse als Tetracyanobis(7-decarboxymethyl-7,8-didehydro-5-methylen-5-norcobyrinsäure)-dodecamethylester (2) ergibt.
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    URL: http://dx.doi.org/10.1002/jlac.198219820113
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  • 24
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    Synthese von cis- und trans-Eninen in der Reihe der 12-und 15-Ringe (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1366-1374 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of cis- and trans-Enynes in the Class of 12- and 15-membered Ring SystemsSynthesis of (E)-1-cyclododecen-3-yne (E-2a) leads to the isolation of the first trans-enyne with geometrical ring strain. E-2a isomerizes thermally to give the Z-configuration Z-2a in a very smooth reaction. For systematical investigations the 15-membered ring enynes E-5a and Z-5a were generated. They behave like openchained 1,3-enynes.
    Notes: Die Synthese von (E)-1-Cyclododecen-3-in (E-2a) führt zur Isolierung des ersten trans-Enins mit geometrischer Ringspannung. E-2a wandelt sich thermisch leicht in die Z-Konfiguration Z-2a um. Zur systematischen Untersuchung werden die 15-Ring-Enine E-5a und Z-5a hergestellt. Sie verhalten sich wie offenkettige 1,3-Enine.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198219820713
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    Synthesen mit aliphatischen Dialdehyden, XXXIV. Versuche zur Darstellung von Brom-(Chlor-)fluormalonaldehyd sowie von Fluor(methyl)- und Fluor(phenyl)malonaldehyd (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1348-1358 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XXXIV.  -  Attempts to Synthesize Bromo- or Chloro-fluoromalonaldehyde and Fluoro(methyl)- or Fluoro(phenyl)malonaldehydeFluorination of the potassium salts of chloro- (3), methyl- (10), and phenylmalonaldehyde (12) with perchloryl fluoride in methanol at 27-28°C leads to the 2-substituted fluoromalonaldehyde bis(methyl semiacetals) 4 and 13a, b, respectively, which in turn can be converted into the more stable derivatives 5, 7-9 of chlorofluoromalonaldehyde (2a), and 14a, b of fluoro(methyl)- and fluoro(phenyl)malonaldehyde, respectively. The corresponding free 2,2-disubstituted malon-aldehydes mentioned in the title were not available due to their tendency to polymerize. Attempts to obtain fluoro(methyl)malonaldehyde from its bis(dimethyl acetal) 14a gave only a “dimer”, the 9,10-difluoro-9,10-dimethyl-2,4,6,8-tetraoxaadamantane (15). The derivatives 5, 7-9 as well as 14a, b of the 2,2-disubstituted malonaldehydes are useful bifunctional C3-synthons.
    Notes: Fluorierung der Kaliumsalze von Chlor- (3), Methyl- (10) und Phenylmalonaldehyd (12) mit Perchlorylfluorid in Methanol bei 27-28°C führt zu den 2-substituierten Fluormalonaldehyd-bis(methylhalbacetalen) 4 bzw. 13a, b, die in die stabileren Derivate 5, 7-9 des Chlorfluor-malonaldehyds (2a) bzw. 14a, b von Fluor(methyl)- und Fluor(phenyl)malonaldehyd übergeführt werden können. Die entsprechenden freien, im Titel genannten Malonaldehyde konnten wegen ihrer Neigung zur Polymerisation nicht erhalten werden. Versuche, den Fluor(methyl)malon-aldehyd aus seinem Bis(dimethylacetal) 14a zu gewinnen, führten zu einem “Dimeren”, dem 9,10-Difluor-9,10-dimethyl-2,4,6,8-tetraoxaadamantan (15). Die Derivate 5, 7-9 sowie 14a, b der 2,2-disubstituierten Malonaldehyde sind nützliche bifunktionelle C3-Synthesebausteine.
    Additional Material: 1 Ill.
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    Über die Veresterung von Glycerinaldehyd-diethylacetal mit einigen Aminosäuren (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 366-371 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Esterification of Glyceraldehyde Diethyl Acetal with Some Amino AcidsGlyceraldehyde diethylacetal was selectively esterified in the 2- and 3-position, respectively, by several Z-amino acids. Attempts to remove the protective groups usually result in hydrogenolytic or hydrolytic cleavage of the ester bond.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219820220
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    Synthese cyclischer N-(2-Arylvinyl)harnstoffe durch Wittig-Reaktion (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 372-375 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Cyclic N-(2-Arylvinyl)ureas by Wittig ReactionTriphenyl(α-ureidoalkyl)phosphonium salts (1, 2, 8) react with aromatic aldehydes and ketones to give quite easily N-(2-arylvinyl)ureas (4a, b, 5a-i, 7, 9) according to Wittig.
    Additional Material: 2 Tab.
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    Thiophosphatidsäureester mit C—S—P-Bindung (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1-7 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiophosphatidic Acid Esters Containing a C—S—P BondThiophosphatidic acid and the following thiophosphatidic acid esters containing a C—S—P bond were synthesized: O,O-dimethyl S-(2,3-distearoyloxypropyl) thiophosphate (4). O-methyl S-(2,3-distearoyloxypropyl) thiophosphoric acid (4a), and O,O-bis(trimethylsilyl) S-(2,3-distearoyloxypropyl) thiophosphate (6). The structures were proved by NMR and IR spectra. It was demonstrated that O,O-dimethyl S-(2,3-isopropylidenedioxypropyl) thiophosphate (3) can be obtained from 2,3-isopropylidenedioxy-1-propanethiol (1) in good yield and acylated to yield 4.
    Notes: Thiophosphatidsäure und folgende Thiophosphatidsäureester mit C—S—P-Bindung wurden synthetisiert: Thiophosphorsäure-O,O-dimethyl-S-(2,3-distearoyloxypropyl)ester (4), Thiophosphorsäure-O-methyl-S-(2,3-distearoyloxypropyl)ester (4a) und Thiophosphorsäure-O,O-bis(trimethylsilyl)-S-(2,3-distearoyloxypropyl)ester (6). Die Strukturen wurden durch NMR- und IR-Spektren bestätigt. Es wurde gezeigt, daß Thiophosphorsäure-O,O-dimethyl-S-(2,3-isopropylidendioxypropyl)ester (3) mit guter Ausbeute aus 2,3-Isopropylidendioxy-1-propanthiol (1) erhalten und zu 4 acyliert werden kann.
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    URL: http://dx.doi.org/10.1002/jlac.198419840102
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    Synthese von 4-Penten-4-oliden (γ-Methylen-γ-butyrolactonen) über 4-Pentensäuren (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 15-30 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 4-Penten-4-olides (γ-Methylene-γ-butyrolactones) vis 4-Pentenoic Acids4-Penten-4-olides (γ-Methylene-γ-butyrolactones) 7 are easily accessible starting from allylic alcohols 1, which on ortho ester Claisen rearrangement and hydrolytic work-up furnish 4-pentenoic acids 5. The latter on iodolactonization and hydrogen iodide elimination by means of 1,8-diaza-bicyclo[5.4.0]undec-7-ene (DBU) furnish 7, in good over-all yield and with variable substitution patterns.  -  Iodolactonization under kinetic control shows moderate 1,2- or 1,3-asymmetric induction (≳ 3:1 and ca. 2:1, respectively). The composition of the iodolactone mixtures 6 as well as the individual relative configurations are deduced from 1H and 13C NMR data.  -  Similarly, the spirobipentenolide 13 is obtained starting from diethyl diallylmalonate (9) via 11 resulting from ester iodocyclization.
    Notes: 4-Penten-4-olide (γ-Methylen-γ-butyrolactone) 7 sind aus Allylalkoholen 1 durch Orthoester-Claisenumlagerung und Hydrolyse zu 4-Pentensäuren 5, anschließende Iodlactonisierung und HI-Abspaltung mit 1,8-Diazabicyclo[5.4.0]undec-7-en (DBU) in guter Gesamtausbeute und variablem Substitutionsmuster leicht zugänglich.  -  Die Iodlactonisierung unter kinetischer Kontrolle zeigt mäßige 1,2- oder 1,3-asymmetrische Induktion (≳ 3:1 bzw. ca. 2:1). Die Zusammensetzungen der Iodlactongemische 6 sowie die relativen Konfigurationen werden aus 1H- und 13C-NMR-Daten abgeleitet.  -  Das Spirobipentenolid 13 wird in ähnlicher Weise aus Diallylmalonsäure-diethylester (9) über 11 (durch Ester-Iodlactonisierung) erhalten.
    Additional Material: 7 Tab.
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    Studien auf dem Gebiet der Naturstoffchemie, 89. Halogenierungsreaktionen des 1,3-Dihydroxy-10-methyl-9(10H)-acridinons und seiner Ether  -  eine einfache regiospezifische Synthese des Acronycins (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 31-38 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on the Chemistry of Natural Organic Materials, 89.  -  halogenation Reactions of 1,3-Dihydroxy-10methyl-9(10H)-acridinone and its Ethers  -  A Simple Regiospecific Synthesis of AcroyncineIodination of 1,3-dihydroxy-10-methyl-9-acridone (2c) and its ethers 2a and 2b gave the corresponding 2-iodo derivatives 3a-c. Bromination of 2a with NBS yielded 2-bromo-(10), 4-bromo- (11), as well as small amounts of 2,4-dibromo-1,3-dimethoxy-10-methyl-9-acridone (12). Under the same conditions from 2c 2-bromo-1,3-dihydroxy-10-methyl-9-acridone (13) has been obtained. Chlorination of 2a with SO2Cl2 in CHCl3 gave-4-chloro- (14) and 2,4-dichloro-1-hydroxy-3-methoxy-10-methyl-9-acridone (15). The reaction of 3b with copper(I) phenyl- and copper(I) isopropenylacetylide yielded the corresponding 2-substituted 4-methoxy-6-methylfuro[2,3-α]acridin-11(6H)-ones 6a and 6b, respectively. From the condensation reaction of 3c with 3-chloro-3-methyl-1-butyne noracronycine (8) has been obtained.
    Notes: Die I2/HIO4-Iodierung von 1,3-Dihydroxy-10-methyl-9-acridon (2c) und seiner Ether 2a und 2b ergab die entsprechenden 2-Iod-Derivate 3a-c. Bromierung von 2a mit NBS führte zu 2-Brom-(10), 4-Brom-(11) sowie geringen Mengen von 2,4-Dibrom-1,3-dimethoxy-10-methyl-9-acridon (12). Unter denselben Bedingungen lieferte 2c 2-Brom-1,3-dihydroxy-10-methyl-9-acridon (13). Chlorierung von 2a mit SO2Cl2 in CHCl3 ergab 4-Chlor-(14) und 2,4-Dichlor-1-hydroxy-3-methoxy-10-methyl-9-acridon (15). Umsetzen von 3b mit Kupfer(I)-phenyl- bzw. Kupfer(I)-isopropenylacetylid führte zu den 2-substituierten 4-Methoxy-6-methylfuro[2,3-α]acridin-11(6H)-onen 6a und 6b. Die Reaktion von 3c mit 3-Chlor-3-methyl-1-butin ergab Noracronycin (8).
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    Synthese des Methylethers der Herzgift-Methylreduktinsäure aus D-Glucose (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 66-77 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the Methyl Ether of “Herzgift-Methylreduktinsäure” Starting from D-GlucoseThe methyl ether 5 of „Herzgift-Methylreduktinsäure“ (2), a degradation product of the Calotropis cardenolides, has been synthesized starting from D-glucose as the chiral pool. The configuration of 2, previously based on the results of degradation, is confirmed by the synthesis of 5.
    Notes: Der Methylether 5 der „Herzgift-Methylreduktinsäure“ (2), eines Abbauproduktes der Calotropis-Cardenolide, wird in einer mehrstufigen Synthese aus D-Glucose als chiralem Ausgangsmaterial hergestellt. Damit wird die durch Abbaureaktionen getroffene Konfigurationszuordnung für 2 durch Synthese von 5 bestätigt.
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    (Aminoethinyl)metallierungen, 13. Synthese und Reaktionen von 3-Aminopropiolamidinen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 85-97 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminoethynyl Metallations, 313.  -  Synthesis and Reactions of 3-AminopropiolamidinesThe lithium aminoacetylides 1 react with the carbodiimides 2 to give the lithium propiolamidinates 3, which are hydrolyzed to yield the 3-aminopropiolamidines 4. 3 can directly be converted into the persubstituted ynamine carboxamidines 5 by adding methyl iodide. The amidines 4 with less activated C/C-triple bonds (NR1R2 = N(Me)Ph or NPh2) react with thioformaldehyde dioxide or with diphenyl ketene exclusively at the NH group with formation of the sulfonamides 6 or of an carboxamide 7. The more reactive (diethylaminoacetylene)carboxamidine 4h adds a second molecule of ketene to furnish the cyclobutenone derivative 8. The propiolamidine 4b with a diphenylamino group at the triple bond reacts with concentrated hydrochloric acid under formation of the amidinium salt 9 and partly by addition of a second molecule of hydrochloride to the triple bond to give 10. Adding tosyl azide to 4 we obtained via the triazole 11 by two successive 1,5-cyclizations the 4-amidino-1,2,3-triazoles 12. The 3-aminopropiolamidines 4 bearing at least one aryl group in the amidine moiety cyclize to give the 2,4-diaminoquinolines 17 if they are chromatographed on silica gel. The same or analogously substituted quinolines 17 are obtained by the reaction of the simple ynamines 15(H, Me, or Ph in the β-position) with the corresponding carbodiimides 2 2-Anilino-4-diethylamino-3-methylquinoline (17e) is hydrolyzed in acidic solution to give the 4-quinolone derivative 19.
    Notes: Die Lithium(aminoacetylide) 1 reagieren mit den Carbodiimiden 2 zu den Lithiumpropiolamidinaten 3, deren Hydrolyse die 3-Aminopropiolamidine 4 liefert. Mit Methyliodid entstehen aus 3 die persubstituierten Inamincarboxamidine 5. Die Amidine 4 reagieren bei geringer Aktivierung der Dreifachbindung [NR1R2 = N(Me)Ph oder NPh2] mit Sulfen oder mit Diphenylketen ausschließlich an der NH-Gruppe unter Sulfonamid- bzw. Carboxamidbildung (s. 6 und 7). Das reaktivere (Diethylaminoacetylen)carboxamidin 4h addiert bei der Umsetzung mit Diphenylketen zusätzlich ein Ketenmolekül an der Dreifachbindung zum Cyclobutenonderivat 8. Der Propiolamidinvertreter 4b mit Diphenylaminogruppe an der Dreifachbindung reagiert mit konz. Salzsäure unter Bildung des Amidiniumsalzes 9, und unter Addition von Chlorwasserstoff an die Dreifachbindung zu 10, Mit Tosylazid erhält man nach der Triazolbildung 11 in zwei aufeinanderfolgenden 1,5-Cyclisierungen die 4-Amidino-1,2,3-triazole 12. Die 3-Aminopropiolamidine 4 mit mindestens einer Arylgruppe im Amidinteil cyclisieren im Kontakt mit Silicagel zu den 2,4-Diaminochinolinen 17. Die gleichen oder analog substituierten Chinoline 17 erhält man auch durch Umsetzung der einfachen Inamine 15 (Wasserstoff, Methyl- oder Phenylgruppen in β-Position) mit den entsprechenden Carbodiimiden 2. 2-Anilino-4-diethylamino-3-methylchinolin (17e) wird in saurem Medium zum 4-Chinolonderivat 19 hydrolysiert.
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    Synthese der Pterocarpane aus Swartzia laevicarpa (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 127-132 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Pterocarpan Constituents of Swartzia laevicarpaThe synthesis of 2,8-dihydroxy-3,4-dimethoxy- (1), 2,8-dihydroxy-3,9,10-trimethoxy- (2), 8-hydroxy-3,4,9,10-tetramethoxy- (3), and 2,8-dihydroxy-3,4,9,10-tetramethoxypterocarpan (4)  -  each of them as racemate  -  confirmed the constitution of four new pterocarpans isolated from Swartzia laevicarpa.
    Notes: Durch die eindeutige Synthese von jeweils racemischem 2,8-Dihydroxy-3,9-dimethoxy- (1), 2,8-Dihydroxy-3,9,10-trimethoxy-(2), 8-Hydroxy-3,4,9,10-tetramethoxy-(3) und 2,8-Dihydroxy-3,4,9,10-tetramethoxypterocarpan (4) wurde die Konstitution von vier neuen, aus Swartzia laevicarpa isolierten Pterocarpanen bestätigt.
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    Diastereoselektive Synthese von (1RS)-endo-Brevicomin (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 147-156 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diastereoselective Synthesis of (1RS)-endo-Brevicomin(1RS-endo-Brevicomin (1) is synthesized starting from trans-1-bromo-2-pentene. Synthetic key step is the diastereoselective linkage of erythro-2,3-butanediol to 3,3-dimethoxy-1-(phenylsulfonyl)-butane or methyl 4,4-dimethoxypentanoate.
    Notes: (1RS)-endo-Brevicomin (1) wird ausgehend von trans-1-Brom-2-penten synthetisiert. Schlüsselreaktion ist die diastereoselektive Verknüpfung von erythro-2,3-Butandiol mit 3,3-Dimethoxy-1-(phenylsulfonyl)butan oder 4,4-Dimethoxypentansäure-methylester.
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    Cycloarene, eine neue Klasse aromatischer Verbindungen, IV. Versuche zur Synthese des Cyclo[d.e.e.d.e.e.d.e.e]nonakisbenzens und des Cyclo[d.e.d.e.d.e.d.e.d.e]decakisbenzens (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 742-760 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloarenes, a New Class of Aromatic Compounds, IV. - Attempts to Synthesize cyclo-[d.e.e.d.e.e.d.e.e]nonakisbenzene and cyclo[d.e.d.e.d.e.d.e.d.e]decakisbenzeneWith the aim to synthesize 3 the dithiaphane 5 was prepared from which via 6 the [2]anthraceno[2]benzo[c]phenanthrenophane 10 was obtained. The corresponding [2.2]phane-diene 11 was prepared from 5 via 12 and 13. The conformations of 5, 10, and 11 yielded 14 which was dehydrogenated to yield the new aromatic system 15. The second internal ring closure to 3 so far did not succeed. - As precursors for the synthesis of 4 the [2]dibenzo[a, j]anthraceno[2]anthraceno[2]phenanthrenophanes 19 and 20 as well as the corresponding [2.2]phane-dienes 23 and 24 were prepared via 18.Attempts to cyclodehydrogenate to 4 failed. In this context the conformations of 19, 20, 23, and 24 are discussed based on 1H NMR spectra.
    Notes: Mit dem Ziel der Synthese von 3 wurde das Dithiaphan 5 dargestellt, das über 6 in das [2]Anthraceno[2]benzo[c]phenanthrenophan 10 übergeführt wurde. Das entsprechende Phandien 11 wurde aus 5 über 12 und 13 erhalten. Die Konformationsverhältnisse von 5, 10 und 11 werden anhand der 1H-NMR-Spektren diskutiert. - Aus 11 entstand durch nicht-oxidative Photocyclisierung 14, das zu dem neuen aromatischen Bindungssystem 15 dehydriert wurde. Der zweite innere Ringschluß zu 3 gelang bisher nicht. - Als Vorstufen für die Synthese von 4 wurden über 18 die [2]Dibenz[a, j]anthraceno[2]phenanthrenophane 19 und 20 sowie die entsprechenden [2.2]Phandiene 23 und 24 dargestellt. Versuche der Cyclodehydrierung zu 4 schlugen fehl. In diesem Zusammenhang werden die Konformationsverhältnisse von 19, 20, 23 und 24 auf der Basis von 1H-NMR-Daten diskutiert.
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    Selektive Reaktionen von Hydroazulenen: Chirale Norcaranderivate über die Umsetzung eines Dihydroazulens mit Singulettsauerstoff (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 773-782 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Selective Reactions of Hydroazulenes: Chiral Norcarane Derivatives by the Reaction of a Dihydroazulene with Singlet OxygenPhotosensitized oxygenation of the dihydroazulene 6 affords the two peroxides 7 and 8 in good overall yield. The major product is derived from the “norcaradiene” of 6. The cycloaddition with singlet oxygen occurs stereospecifically. Consecutive reaction of 7 yield chiral norcarane derivatives in stereospecific ways. Thus, by thermolysis of 7 the bisepoxide 10 is formed; reaction of 7 with triethylamine leads to the hydroxyketone 11 with MnO2 the homoquinone 13 is formed. The structures are established by spectroscopic methods.
    Notes: Die Umsetzung des Dihydroazulens 6 mit Singulettsauerstoff ergibt die beiden Peroxide 7 und 8. Das Hauptprodukt 7 leitet sich vom “Norcaradien” des Hydroazulens 6 ab. Die 1O2-Addition erfolgt stereoselektiv. Folgereaktionen von 7 ergeben chirale Norcaranderivate: Thermolyse führt zum Bisepoxid 10, mit Triethylamin entsteht das Hydroxyketon 11 und Triphenylphosphan führt unter Sauerstoffabspaltung zu den Vinyloxiranen 12a und 12b. Bei diesen Reaktionen wird jeweils nur ein Diastereomeres gebildet. Die Oxidation von 11 mit Mangandioxid ergibt das Homochinon 13. Für sämtliche Reaktionsprodukte sind spektroskopische Daten angegeben.
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    Synthesen von (+)-Oudemansin und (+)-Epioudemansin aus enantiomerenreinen Vorstufen; absolute Konfiguration des natürlichen (-)-Oudemansins (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 791-801 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of (+)-Oudemansin and (+)-Epioudemansin Starting from Enantiomerically Pure Precursors; Absolute configuration of the Naturally Occurring (-)OudemansinThe syntheses of the four optically pure methyl (E)-3-hydroxy-2-methyl-5-phenyl-4-pentenoates (+)- and (-)-5 as well as (+)- and (-)-6 were achieved by consecutive methylation and protonation of enolates, starting from (+)- and (-)-4. The esters (+)-6 and (-)-5 are used as starting materials to synthesize (+)-oudemansin [(+)-3] and (+)-epioudemansin [(+)-9].
    Notes: Die Darstellung der vier optisch reinen (E)-3-hydroxy-2-methyl-5-phenyl-4-pentensäure-methylester (+)- und (-)-6 gelingt durch aufeinanderfolgende Methylierung und Protonierung von Esterenolaten, ausgehend von (+)- und (-)-4. Die Ester (+)-6 und (-)-5 werden für Synthesen von (+)-Oudemansin [(+)-3] und (+)-Epioudemansin [(+)=9] eingesetzt.
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    Flexible und effektive Synthese für 4-Oxo-2-alkensäuremethylester (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 820-827 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Flexible and efficient Synthesis of Methyl 4-Oxo-2-alkenoatesThe title compounds E are obtained in good yield by low temperature ring cleavage of the easily available methyl 2-siloxycyclopropanecarboxylates C with bromine and subsequent elimination of hydrogen bromide. Due to the variability of C a high flexibility concerning substituents R1-R4 in products E is guaranteed. 2-Alkyl- and 2-methylthio-substituted olefins are thus effectively synthesized. In several cases the initally formed methyl 2-bromo-4-oxoalkanoates F are stable enough to be isolated in high yield.
    Notes: Aus den leicht zugänglichen 2-Siloxycyclopropancarbonsäure-methylestern C erhält man durch Ringöffnung mit Brom bei tiefer Temperatur und anschließender Bromwasserstoffeliminierung die Titelverbindungen E in guten Ausbeuten. Aufgrund der Variationsmöglichkeiten bei C ergibt sich bei den Produkten E eine große Flexibilität bezüglich der Reste R1-R4. So sind auch 2-alkyl- und 2-methylthiosubstituierte Olefine effektiv darstellbar. In einigen Fällen sind die primär gebildeten 2-Brom-4-oxoalkansäure-methylester F so stabil, daß sie in hoher Ausbeute isolierbar sind.
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    Zur Ringöffnung von 2-(Trimethylsilylmethyl)cyclopropancarbonsäure-methylester (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 828-830 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ring Opening of Methyl 2-(Trimethylsilylmethyl)cyclopropanecarboxylateThe reactivity of the title compound 5 is compared with that of methyl 2-siloxycyclopropanecarboxylates. 2. Whereas these are cleaved under various conditions, the less activated derivative 5 undergoes ring opening to yield methyl pentenoate (6a) only with sources of “free” flouride-like tetra-n-butylammonium fluoride.
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    URL: http://dx.doi.org/10.1002/jlac.198419840418
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    Indole und Indolalkaloide, XVIII. Synthese von Tetrahydro- und Hexahydrocarbazol-Derivaten mit N-Substituenten in Position 4 (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 739-744 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Indoles und Indole Alkaloids, XVIII1).  -  Synthesis of Tetrahydro- and Hexahydrocarbazoles with N-Substituents in Position 4Synthesis and properties of some tetrahydro- and hexahydrocarbazoles bearing N-substituents in position 4 are described Tricyclic representatives of this type have been unknown up to this time.
    Notes: Es werden Darstellung und Eigenschaften einiger Tetrahydro- und Hexahydrocarbazol-Derivate mit N-Substituenten in Position 4 beschrieben. Tricyclische Vertreter dieses Typs waren bisher noch nicht bekannt.
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    A Ready Conversion of a Pregnane-20-carboxaldehyde to 17α-Hydroxypregnan-20-ones and Pregn-16-en-20-ones (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1829-1835 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Einfache Umwandlung eines Pregnan-20-carboxaldehyds in 17α-Hydroxypregnan-20-one und Pregn-16-en-20-oneUmsetzung von (20S)-5α-Chlor-3β-hydroxypregnan-20-carboxaldehyd (9, dargestellt in zwei Stufen aus Stigmasterin) mit Sauerstoff und Kalium-tert-butylat sowie anschließend mit Trimethylphosphit lieferte 5α-Chlor-3β,17α-dihydroxypregnan-20-on (6) und 3β, 17α-Dihydroxypregn-5-en-20-on (7). Diese Mischung wurde durch Kaliumhydroxid in 7 übergeführt, während Reaktion mit Pyridinium-dichromat und danach mit Kaliumhydroxid 17α-Hydroxypregn-4-en-3,20-dion (8) ergab. Bromierung-Dehydrobromierung von 9 in einer oder zwei Stufen ergab (Z)- und (E)-5α-Chlor-3β-hydroxypregn-17(20)-en-20-carboxaldehyd (11). Dessen Reaktion mit Sauerstoff und Kaliumhydroxid lieferte 5α-Chlor-3β-hydroxypregn-16-en-20-on (12). Letzteres wurde durch weitere Kaliumhydroxid-Behandlung in 3β-Hydroxypregna-5,16 dien-20-on (13) und mittels Oppenauer-Reaktion, unter Anwendung von überschüssigem Aluminiumisopropylat, in Pregna-4,16-dien-3,20-dion (14) übergeführt.
    Notes: Reaction of (20S)-5α-chloro-3β-hydroxypregnane-20-carboxaldehyde (9, prepared in two steps from stigmasterol) with oxygen and potassium tert-butoxide, followed by trimethyl phosphite treatment, afforded 5α-chloro-3β,17α-dihydroxypregnan-20-one (6) and 3β,17α-dihydroxypregn-5-en-20-one (7). This mixture was converted into 7 by potassium hydroxide treatment, and into 17α-hydroxypregn-4-ene-3,20-dione (8) by reaction with pyridinium dichromate followed by potassium hydroxide treatment. Bromination-dehydrobromination of 9, in one or two steps, afforded (Z)- and (E)-5α-chloro-3β-hydroxypregn-17(20)-ene-20-carboxaldehyde (11). Reaction of 11 with oxygen and potassium hydroxide gave 5α-chloro-3β-hydroxypregn-16-en-20-one (12), which was converted to 3β-hydroxypregna-15,6-dien-20-one (13) by further potassium hydroxide treatment, and to pregna-4,16-diene-3,20-dione (14) by Oppenauer reaction using excess aluminium isopropoxide.
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    Glycosylazide als Ausgangsbasis zur Gewinnung von Nucleosidanalogen, 2. Synthese von Tetrazol-Nucleosiden (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1870-1890 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Glycosyl Azides as Starting Materials for the Synthesis of Nucleoside Analogues, 2.  -  Synthesis of Tetrazole NucleosidesThe β-D-ribofuranosyl azide derivative 1 as well as the corresponding α-anomeric compound 3 yield via Staudinger reaction the same P-N-ylide 2. Treatment with alkyl isocyanates RNCO [R = CH3, (CH3)2CH, C2H5OCOCH2, (S)-C2H5OCOCH(CH3)] affords the diastereomeric carbodiimide derivatives 5 which can be transformed by HN3 regioselectively into the 1-(β-ribofuranosyl)-5-(alkylamino)tetrazole derivatives 6. Partial or total removal of the protecting groups affords the products 7a, c, d, and 7d′-d′". The β-D-mannofuranosyl azide derivative 8 is converted via the P-N-ylide 9 into the carbodiimide 10 and the aminotetrazole derivative 11. The reaction of 2 with phenyl isocyanate yields the 5-[(β- and 5-[(α-D-ribofuranosyl)amino]-1-phenyltetrazoles 18 and 19 passing the carbodiimide intermediates 12 and 13. Additionally the 1-isocyanato sugar derivatives 14 and 15 arise which provide for the formation of the products 16, 17, and 20-22. The ethyl [(β-D-ribofuranosyl)-5-tetrazolyl]acetate 23 is formed by reaction of 2 with the azide of monoethyl malonate. The preparation of the ribosyltetrazole derivatives 26 and 27 can be achieved only by preceding synthesis of the syn/anti mixture 24a/24a originating from 2 and acetyl cyanide followed by treatment with HN3. The α-ribosyliminonitrile 25 is assumed to be an intermediate.
    Notes: Sowohl das β-D-Ribofuranosylazid 1 als auch das α-Anomere 3 liefern bei der Staudinger-Reaktion das gleiche P-N-Ylid 2. Mit Alkylisocyanaten RNCO [R - CH3, (CH3)2CH, C2H5OCOCH2 und (S)-C2H5OCOCH(CH3)] entstehen die Carbodiimidderivate als Diastereomerengemische 5, welche mit HN3 in die 1-(β-Ribofuranosyl)-5-(alkylamino)tetrazole 6 umgewandelt werden. Teilweise oder gänzliche Entfernung der Schutzgruppen führt zu den Produkten 7a, c, d und 7d′-d′". Vom β-D-Mannofuranosylazidderivat 8 aus gelangt man über das P-N-Ylid 9 zum Carbodiimidderivat 10 und schließlich zum Aminotetrazolderivat 11. Die Umsetzung von 2 mit Phenylisocyanat liefert die 5-[(β- und 5-[(α-D-Ribofuranosyl)amino]-1-phenyltetrazole 18 bzw. 19 über die Carbodiimidzwischenstufen 12 und 13. Ferner entstehen die 1-Isocyanatozuckerderivate 14 und 15, welche für die Entstehung der Folgeprodukte 16, 17 und 20-22 verantwortlich sind. Aus 2 und Malonsäure-monoethylester-azid entsteht das Nucleosidderivat 23. Die Darstellung der Ribosyltetrazole 26 und 27 aus 2 läßt sich nur mit Acetylcyanid über das syn/anti-Gemisch 24a/24a′ durch Umsetzung mit HN3 verwirklichen. Als Zwischenstufe wird das (α-Ribosylimino)nitril 25 postuliert.
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    1-Aza- und 1,9-Diazatriptycene (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 381-388 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Aza- and 1,9-DiazatriptycenesThe polycyclic 1,5-diketone 4 is synthesized via the enamine 2 from ketone 1 and phenyl vinyl ketone (3). On reacting the 1,5-diketone 4 with hydroxylamine the expected ring closure to the 1-azatriptycene 6 competes with a ring cleavage by an anomalous Beckmann rearrangement of the oxime yielding the intermediate nitrile 10 which cyclizes to afford the β-anthracenyl-α-aminopyridine 7. [4 + 2] Cycloaddition of dehydrobenzene, generated by diazotation of anthranilic acid, with the pyrido[3,2-g]quinolines 13a, b produces the diazatriptycenes 15a, b.
    Notes: Aus dem Keton 1 wird via Enamin 2 mit Phenylvinylketon (3) das polycyclische 1,5-Diketon 4 hergestellt. Bei dessen Umsetzung mit Hydroxylamin konkurriert der erwartete Ringschluß zum 1-Azatriptycen 6 mit einer Ringöffnung durch anomale Beckmann-Umlagerung des Oxims 9 zum intermediären Nitril 10, das zum β-Anthracenyl-α-aminopyridin 7 cyclisiert. [4 + 2]-Cycloaddition von Dehydrobenzol, das durch Diazotierung von Anthranilsäure erzeugt wird, mit den Pyrido[3,2-g]chinolinen 13a, b ergibt die Diazatriptycene 15a, b.
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    Mehrstufige reversible Redoxsysteme, XXXV. Voltammetrie vinyloger Polyene mit gekreuzt konjugierten Endgruppen und UV/VIS-Spektroskopie ihrer Radikalanionen und -kationen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 354-369 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Multistep Reversible Redox Systems, XXXV.  -  Voltammetry of Vinylogous Polyenes with Cross-Conjugated End Groups and UV/VIS Spectroscopy of their Radical Anions and CationsMost of the polyenes 1-5, especially of the vinylogous 2.n(n = 0-4) and 5.n(n = 1-4) are as well reversibly reduced as oxidized in two steps. As expected the large semiquinone formation constants decrease with increasing chain length (2: KSEMc = 1013-107; KSEMa = 1011-101). The UV/VIS spectra of the radical anions and cations of system 2.n, generated in solution, belong to the violene type; Δλmax ≈ 135 nm (SEMc) and Δλmax ≈ 160 nm (SEM). The potentials of 5.n and the UV/VIS spectra of the radicals of 5.1 point towards twisted molecules. The systems 2.n are the first polyenes which can exist in five oxidation levels and which form persistent radical anions and cations. The redox potentials of 2.n and the UV/VIS spectra of the radical ions are in accordance with the predictions of the Hückel theory.
    Notes: Die Mehrzahl der Polyene 1-5, insbesondere der Vinylogen 2.n (n = 0-4) und 5.n (n = 1-4) werden sowohl reversibel zweistufig reduziert als auch oxidiert. Erwartungsgemäß nehmen die großen Semichinonbildungskonstanten mit wachsender Kettenlänge ab (2: KSEMc = 1013-107; KSEMa = 1011-101). Die UV/VIS-Spektren der in Lösung erzeugten Radikalanionen und-kationen des Systems 2 (n = 0-4) sind vom Violentyp mit Δλmax ≈ 135 nm (SEMc) und Δλmax ≈ 160nm (SEM). Die Potentiale des Systems 5.n sowie die UV/VIS-Spektren der Radikal-Ionen aus 5.1 weisen auf Verdrillung hin. Mit 2.n liegen erstmals Polyene vor, die in fünf Oxidationsstufen existieren können und deren Radikal-Ionen persistente Lösungen bilden. Sowohl die Redoxpotentiale von 2.n als auch die UV/VIS-Spektren der Radikal-Ionen entsprechen den Erwartungen der Hückel-Theorie.
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    Konformationsanalyse, XXIV. Bestimmung der Konformationen von Tri- und Tetrasaccharid-Sequenzen der Core-Struktur von N-Glycoproteinen. Problem der (1 → 6)-glycosidischen Bindung (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 951-976 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Confomational Analysis, XXIV. - determination of the Conformations of Tri-and Tetrasaccharide Sequences of N-Glycoproteins. The problem of the (1 → 6)-glycosidic BondThe preferred solution conformations of the saccharides α-D-Man(1 → 3)-β-D-Man(1 → 4)-D-GIcNAc (1), α-D-Man(1 → 6)-β-Man(1 → 4)-D-GIcNAc (2), and α-D-Man(1 → 3)[α-D-Man(1 → 6)]lβ-D-Man(1 → 4)-D-GIcNAc3), which are known as parts of the core structure of N-glycoproteins, could be established by use of HSEA calculations (HSEA: Hard-Sphere Exo-Anomeric) with the new program GESA (= Geometry of Saccharides) in connection with 1H NMR investigations like NOE experiments, spin-lattice relaxation-time measurements and the observation of selective deshieldings. (1 → 3)- and (1 → 4)-glycosidic bonds show one strongly preferred conformation. The greater flexibility of the (1 → 6)-glycosidic bonds show one strongly preferred conformation. The greater flexibility of the (1 → 6)-glycosidic bond will be discussed in details. For the spectra analysis various 2-D techniques have been used.
    Notes: Von den Sacchariden α-D-Man(1 → 3)-β-D-Man(1 → 4)-D=-GICNAc (1), α-D-Man(1 → 6)-β-D-Man(1 → 4)-D-GIcNAc(2) und α-D-Man(1 → 3)[α-D-Man(1 → 6)]-β-D-Man(1 → 4)-D-GlcNAc(3), die als Core-Struktur in N-Glycoproteinen vorkommen, wurden durch HSEA-Berechnungen (HSEA: Hard-Sphere Exo-Anomeric) mit dem neuen GESA-Programm (GESA: Geometry of Saccharides) die bevorzugten Konformationen bestimmt. Mit Hilfe von 1H-NMR-Experimenten, nämlich NOE-Experimenten, Spin-Gitter-Relaxationszeitmessungen und der Beobachtung selektiver Entschirmungen, ließen sich diese Konformationen in Lösung bestätigen. (1 → 3)- und (1 → 4)-glycosidische Bindungen weisen eine stark bevorzugte Konformation auf. Die weitaus größere Flexibilität der (1 → 6)-glycosidischen Bindung wird besonders diskutiert. Zur Analyse der Spektren wurden verschiedene 2-D-NMR-Techniken angewandt.
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    Reaktionen mit Isocyaniden. Synthese tiefblauer Farbstoffe aus 1,4-Chinonen und Arylisocyaniden (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1003-1012 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Isocyanides. - Synthesis of Dark-blue Dyes from 1,4-Quinones and Aryl Isocyanides1,4-Benzoquinone reacts with aryl isocyanides 2a-d in boiling toluene or xylene forming darkblue 1:2 and 1:4 adducts, the 4,7-isoindolediones 3a-d and the 1,5- and 1,7-bis(arylamino)-benzodipyrrolediones 4a-c and 5a-c, respectively, which can be separated by chromatography. The structure of the 4-methylphenyl isocyanide adducts 3b, 4b, and 5b is established by NMR spectroscopy. The 1:2 adduct 3b reacts with two moles of 4-methylphenyl isocyanide (2b) affording the isomeric 1:4 adducts 4b and 5b. However, in a similar reaction with 4-chlorophenyl isocyanide (2c) surprisingly only the 1,5-bis(arylamino) derivative 8 is isolated. 1,4-Naphthoquinone (10) reacts with 4-methylphenyl (2b or 4-nitrophenyl isocyanide (2d) to yield the 4,9-benzo[f]isoindoles 11b and d, respectively.
    Notes: 1,4-Benzochinon reagiert mit den Arylisocyaniden 2a-d in siedendem Toluol oder Xylol zu tiefblauen 1:2- und 1:4-Addukten, den 4,7-Isoindoldionen 3a-d bzw. den 1,5- und 1,7-Bis(arylamino)benzodipyrroldionen 4a-c und 5a-c, die chromatographisch getrennt werden. Die Struktur der (4-Methylphenyl)isocyanid-Addukte 3b, 4b und 5b wird NMR-spektroskopisch bewiesen. Das 1:2-Addukt 3b ergibt mit zwei Molen (4-Methylphenyl)isocyanid (2b) die isomeren 1:4-Addukte 4b und 5b; mit (4-Chlorphenyl)isocyanid (2c) wird jedoch überraschenderweise nur das 1,5-Bis(arylamino) Derivat 8 isoliert. 1,4-Naphthochinon (10) bildet mit (4-Methylphenyl)-(2b) bzw. (4-Nitrophenyl)isocyanid (2d) die 4,9-Benzo[f]isoindoldione 11b und d.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198419840518
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    Reaktionen von 1,4-Pentadien-3-onen, 22. Darstellung und Struktur der epimeren 3,5-Diaryl-4-hydroxy-1,4-thiazinan-1,1-dioxide (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1013-1023 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 1,4-Pentadien-3-ones, 22. - Synthesis and Structure of the Epimers of 3,5-Diaryl-4-hydroxy-1,4-thiazinane 1,1-DioxidesDistyrylsulfones 1 react with the ambident nucleophile hydroxylamine only by double addition of nitrogen to give 4-hydroxy-1,4-thiazinane derivatives 3. In solution 3 consists of a temperature-dependent equilibrium mixture of two epimers. When heated or when crystallized one of the epimers is depopulated. The above phenomena and structures are elucidated by an X-ray analysis and by NMR spectroscopy.
    Notes: Distyrylsulfone 1 reagieren mit dem ambidenten Nucleophil Hydroxylamin ausschließlich unter doppelter Addition des Stickstoffs zu 4-Hydroxy-1,4-thiazinan-Derivaten 3. Diese bilden in Lösung temperaturabhängige Epimeren-Gleichgewichte. Sowohl beim Erwärmen als auch beim Auskristallisieren erfolgt Depopulation eines Epimers. Strukturen und Phänomene werden durch Röntgenstrukturanalyse und NMR-Spektroskopie geklärt.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198419840519
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    Über die Iodierung von Monosaccharid-Derivaten mit Iodtrimethylsilan (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1052-1055 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Iodation of Monosaccharide Derivatives with IodotrimethylsilaneWith iodotrimethylsilane generated in situ, iodine can be introduced into carbohydrate derivatives with high selectivity. The rate of iodination at the anomeric center of the C-1-substituted 2,3,4,6-tetra-O-acetyl-D-glucopyranoses 1a-d decreases in the following series: OAc 〉 OBz ≈ OH » OCH3. - Hydroxy groups or their ethers 3b, c react distinctively to give the trimethylsilyl ethers, whereas the primary react to yield the 6-deoxy-6-iodo derivatives 5. The 1-O-acetyl-6-hydroxy derivative 6a and its 6-O-trityl ether form 2,3,4-tri-O-acetyl-6-deoxy-6-iodo-α-D-glucopyranosyl iodide (7).
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    Versuche zur Synthese des Polystachins (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1068-1077 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: An Attempted Synthesis of Polystachin[1′RS(3RS)]-1-(2,3-Dihydro-4-hydroxy-6-methoxy-1-benzofuran-3-yl)-2-methyl-1,2-propandiol (21), a partial structure of the title substance 1 was synthetized in 11 steps from phloroglucinol. The key steps were the oxidative rearrangement of the benzylidenacetone derivative 5 by Tl(NO3)3 in methanol to yield the 2-aryl-1,1-dimethoxythane 8 followed by ring closure involving the hydroxy group of 9 liberated by debenzylation. Conversion of 21 into compounds of structure 1 was just as unsuccessful as the synthesis of rac-polystachin (rac-1) from tachrosin (23 via the flavone derivative 29.
    Notes: [1′RS(3RS)]-1-(2,3-Dihydro-4-hydroxy-6-methoxy-1-benzofuran-3-yl)-2-methyl-1,2-propandiol (21), eine Teilstruktur der Titelsubstanz 1, wurde aus Phloroglucin in 11 Schritten synthetisiert. Als Schlüsselreaktion diente die oxidative Umlagerung des Benzalacetonderivates 5 mit Tl(NO3)3 in Methanol zu dem 2-Aryl-1,1-dimethoxyethan 8 gefolgt vom Ringschluß an der durch Entbenzylierung freigesetzten Hydroxygruppe von 9. Die Überführung von 21 in Verbindungen der Struktur 1 blieb ebenso erfolglos wie die Synthese von rac-Polystachin (rac-1) aus Tachrosin (23) über das Flavonderivat 29.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198419840603
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    Masthead (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982) 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820601
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    Synthese neuer 4,4-Diaryl-2-chlor-2-buten-4-olide und einfacher Zugang zu 1,1-Diphenylinden-3-carbonsäure (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1017-1021 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of New 4,4-Diaryl-2-chloro-2-buten-4-olides and a Simple Route to 1,1-Diphenylindene-3-carboxylic AcidOn heating in dimethylformamide, 4,4-diaryl-2,3-dichloro-2-butenoic acids 2 cyclize to give new 4,4-diaryl-2-chloro-2-buten-4-olides 3. Reaction of 1,2,4-triazole or pyrazole with 3 yields 4,4-diaryl-3-azolyl-2-buten-4-olides 5.  -  Friedel-Crafts reaction of 3a with benzene yields 1,1-diphenylindene-3-carboxylic acid (7).
    Notes: 4,4-Diaryl-2,3-dichlor-2-butensäuren 2 cyclisieren beim Erwärmen in Dimethylformamid zu neuen 4,4-Diaryl-2-chlor-2-buten-4-oliden 3. Mit 1,2,4-Triazol oder Pyrazol reagiert 3 zu 4,4-Diaryl-3-azolyl-2-buten-4-oliden 5.  -  Friedel-Crafts-Reaktion von 3a mit Benzol führt zu 1,1-Diphenyl-inden-3-carbonsäure (7).
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219820602
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    Zur Chemie des (1α,2β,5β,6α,7β,8β)-3,4-Dioxotricyclo[4.2.1.02,5]-nonan-7,8-dicarbonsäure-dimethylesters (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1109-1116 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Dimethyl [1α,2β,5α,6β,7α,8β]-3,4-Dioxotricyclo[4.2.1.02,5]nonane-7,8-dicarboxylateThe reaction of the cyclobutanedione 1 with urea or substituted thioureas provides by double addition the heterocyclic compounds 2a-d. Hydrazines react to give monohydrazones 3 or, by loss of nitrogen, hydrazones of type 4; no formation of osazones was observed. The reaction with o-phenylenediamine yields the quinoxaline 5. Reduction of 1 with sodium tetrahydroborate leads stereoselectively to the glycol 6. Treatment of 1 with sodium methoxide causes benzilic acid rearrangement yielding the annulated cyclopropanecarboxylate 7 with retention of the configuration of the other carbon atoms. Ring enlargement reactions yield either by radiation of 1 via oxacarbenes compound 14 or by oxidation the anhydride 8 which can be reduced to yield the γ-lactone 9.
    Notes: Die Umsetzung des Cyclobutandions 1 mit Harnstoff oder substituierten Thioharnstoffen führt durch zweifache Addition unter Cyclisierung zu den Imidazolidinonen bzw. -thionen 2a-d. Hydrazinabkömmlinge liefern Monohydrazone 3 oder unter Stickstoffabspaltung Hydrazone vom Typ 4; Osazonbildung wurde nicht beobachtet. Mit o-Phenylendiamin entsteht unter Kondensation das Chinoxalin 5. Die Reduktion von 1 mit Natrium-tetrahydroborat liefert stereoselektiv das Glycol 6. Mit Natriummethanolat findet eine Benzilsäure-Umlagerung zum anellierten Cyclopropancarbonsäureester 7 unter Erhaltung der Konfiguration der restlichen C-Atome statt. Ringerweiterungen lassen sich sowohl photochemisch über Oxacarbene zu 14 als auch durch Oxidation zum Anhydrid 8 durchführen, das durch anschließende Reduktion das Norbornan-anellierte γ-Lacton 9 liefert.
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    URL: http://dx.doi.org/10.1002/jlac.198419840608
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    Synthesen mit α-metallierten Isocyaniden, LIII. Synthese von 2,3-Epoxy-2-isocyanalkansäure-methylestern (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 608-611 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with α-Metalated Isocyanides, LIII.  -  Synthesis of Methyl 2,3-Epoxy-2-isocyanoalkanoatesThe title compounds were synthesized from methyl α-isocyanoacrylates 2 with H2O2 (in sodium hydroxide solution) or with m-chloroperbenzoic acid (in methanol/sodium methoxide)
    Additional Material: 1 Tab.
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    Synthesis and Biological Activities of the Antibiotic B 371 and its Analogs (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 600-607 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese und biologische Aktivität des Antibiotikums B 371 und seiner StrukturvariantenDie Synthesen der Titelverbindung 1 und einer Reihe von Strukturvarianten des Typs 4 werden beschrieben. Die antimikrobiellen Aktivitäten dieser Vinylisocyanide, die in β-Position entweder ein Indolderivat oder eine Aryl- oder 2-Thienylgruppe tragen, wurden im Plattentest gegenüber Escherichia coli, Bacillus subtilis und Mucor muhei TÜ 284 geprüft (Tab. 1). Einige der Verbindungen 4 sind stärker wirksam als die natürlich vorkommende Stammverbindung 1.  -  Eine Serie von Alkyl-2-isocyanacrylaten des Typs 5 wurde in den Test einbezogen. Einige davon sind außerordentlich stark aktiv (Tab. 2). Die Aktivität geht in allen Fällen verloren, wenn man die Isocyangruppe zur Formamidogruppe hydrolysiert (4 → 6).
    Notes: The synthesis of the title compound 1 is described as well as the syntheses of a series of structural analogs of type 4. The antimicrobial in vitro activity of these vinyl isocyanides, substituted in β-position either by an indole derivative or by an aryl or 2-thienyl group, was tested against Escherichia Coli, Bacillus subtilis, and Mucor muhei TÜ 284 (Table 1). Some of the compounds 4 display higher activity than the naturally occurring parent compound 1.  -  A variety of alkyl 2-isocyanoacrylates of type 5 were included in the biological test. Some of them display exceptionally high antimicrobial activity (Table 2). Upon conversion of the isocyano group into the formamido group (4 → 6), the biological activity is lost.
    Additional Material: 2 Tab.
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    [2.2](2,7)Anthracenophan: Synthese und Konformations-Untersuchungen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 615-617 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [2.2](2,7)Anthracenophane: Synthesis and Conformational Studies[2.2](2,7)Anthracenophane (3) was synthesized via the dithia[3.3]anthracenophane 6 and the disulfone 7 derived therefrom. From conformational studies based on 1H NMR a rigid anti conformation was assigned to 3, contrary to 6.
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    Mehrstufige, reversible Redoxsysteme, XXXVI. 11,11,12,12-Tetracyan-9,10-anthrachinodimethan (TCNAQ) und seine Derivate: Synthese und Redoxeigenschaften (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 618-621 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multistep, Reversible Redox Systems, XXXVI.  -  11,11,12,12-Tetracyano-9,10-anthraquinodimethane (TCNAQ) and its Derivatives: Synthesis and Redox PropertiesTitle compounds 3Ba-d are synthesized from the corresponding anthraquinones and malononitrile with titanium tetrachloride/pyridine. By comparison of the potentials and semiquinone formation constants of 1B-3B with those of the corresponding quinones 1A-3A strong distortion of the biscyanomethylene groups in 2B and especially 3B is derived.
    Additional Material: 1 Tab.
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    Stereospecific Syntheses of D-Ossamine and D-Tolyposamine (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 636-640 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereospezifische Synthesen von D-Ossamin und D-Tolyposamin2,3,4,6-Tetradesoxy-4-(dimethylamino)-D-threo-hexose (D-Ossamin, 7), der Aminozuckerrest des Pilzmetaboliten Ossamycin und 4-Amino-2,3,4,6-tetradesoxy-D-erythro-hexose (D-Tolyposamin, 12), das Enantiomere des Zuckerrestes des antibiotisch wirksamen Tolypomycins wurden aus D-Glucose über Hex-2-enopyranoside synthetisiert.
    Notes: 2,3,4,6-Tetradesoxy-4-(dimethylamino)-D-threo-hexose (D-ossamine, 7), the amino sugar fragment from the fungal metabolite ossamycin, and 4-amino-2,3,4,6-tetradeoxy-D-erythro-hexose (D-tolyposamine, 12), the enantiomeric constituent of the antibiotic tolypomycin, have been synthesized from D-glucose via hex-2-enopyranosides.
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    Synthesen mit aliphatischen Dialdehyden, XXXVIII. Darstellung und Eigenschaften von Cycloalkylmalonaldehyden (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 649-679 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XXXVIII. - Synthesis and Properties of CycloalkylmalonaldehydesVilsmeier formylation cycloalkyl-substituted enol ethers (7, 14a - c, 23) yields the cycloalkylmalonaldehydes 1- 5 for the first time. In solution 1 - 5 with suitable electrophiles and nucleophiles leads to cycloalkyl-substituted open-chain (29, 30), carbocyclic (31) as well as heterocyclic compounds (32-40) with peculiar properties due to the presence of the lipophilic cycloalkyl group.
    Notes: Durch Vilsmeier-Formylierung cycloalkylsubstituierter Enolether (7, 14a - c, 23) werden die Cycloalkylmalonaldehydes 1 - 5 erstmals dargestellt. In Lösung liegen 1 - 5 in der (E)-s-(E)-Enolform als vinyloge Carbonsäuren vor. Reaktion von 1-5 mit geeigneten Elektrophilen und Nucleophilen führt zu cycloalkylsubstituierten offenkettigen (29, 30), carbocyclischen (31) und heterocyclischen Verbindungen (32-40) mit besonderen, durch die lipophile Cycloalkylgruppe hervorgerufenen Eigenschaften.
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    (2′→ 5′)- und (3′→ 5′)- Tubercidylyl-tubercidine - Synthese über Phosphit- Triester und Untersuchungen zur Sekundärstruktur, (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 692-707 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (2′→5′) and (3′→′)-Tubercidylyl-tubercidins - Synthesis via Phosphite Triester and Investigation of Secondary StructureThe (2′→ 5′)- and (3′→5′)-linked dinucleoside monophosphates 3e and 2e of tubercidin were synthesized by condensation of the monomers 1c or 1b with dichloromethoxyphosphane. By 1H NMR studies it could be demonstrated that the conformation of these nucleobases is different from that in (3′→ 5′)ApA and (2′→ 5′)ApA. From thermodynamic parameters, as well as from hypochromicity, a stronger base - base interaction in 3e than in 2e was deduced. Single-strand specific nuclease S1 hydrolyses 2e at a much higher rate than (3′→ 5′)ApA demonstrating that the enzyme is sensitive towards modification of the aglycone. Condensation of the 5′-deprotected dimer 3b with the monomer 1c followed by complete deprotection yields (2′→ 5′)TupTuTu (4e), which is an analogue of (2′→ 5′)ApApA, the triphosphate of which is antivirally active.
    Notes: Die (2′→ 5′)- und (3′→ 5′)-verknüpften Dinucleosid-monophosphate 3e und 2e des Tubercidins werden aus den Vorstufen 1b oder 1c und 1a durch Kondensation mit Dichlormethoxyphosphan erhalten. Mit 1H-NMR-Untersuchungen konnte gezeigt werden, daß die Nucleobasen eine andere Konformation als im (2′→ 5′)- oder (3′→ 4′)ApA einnehmen. Aus thermodynamischen Parametern sowie der Hypochromizität ergibt sich für 3e eine größere Basenwechselwirkung als für 2e. Einzelstrang-spezifische Nuclease S1 spaltet 2e deutlich schneller als (3′→ 5′)ApA und reagiert damit empfindlich auf die Aglyconmodifikation. Die Kondensation des 5′-entschützten Dimers 3b mit dem Monomer 1c, gefolgt von der Abspaltung der Schutzgruppen, führt zu (2′→ 5′)-TupTupTu (4e). Dies stellt ein Analogon von (2′→ 5′)ApApA dar, das als Triphosphat antiviral wirksam ist.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198419840407
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    Regio- und Stereoselektivität der Lactonbildung bei der Hydrolyse der PO-Olefinierungsprodukte von α,β-Epoxycyclohexanonen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1150-1157 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regio- and Stereoselectivity of the Lactone Formation via Hydrolysis of the PO-Olefination Products of α,β-EpoxycyclohexanonesPO-Olefination of the diastereomeric pulegone oxides 1 and 2 with 9a leads to (E,Z) esters, 1 affording mainly (E)-3, and 2 predominantly (Z)-4. (Z)-4 hydrolyzes to give a mixture of γ- and δ-lactones 6-8; whereas (Z)-3 yields stereoselectively the δ-lactone 5.  -  The epoxy ketone 12 reacts with 9b to give the (E,Z) ester 13. (Z)-13 stereoselectively yields the γ-lactone 14.
    Notes: Bei der PO-Olefinierung der diastereomeren Pulegonepoxide 1 und 2 mit 9a erhält man (E,Z)-Säureester, und zwar aus 1 überwiegend (E)-3, aus 2 vorwiegend (Z)-4. (Z)-4 hydrolysiert zum γ- und δ-Lactongemisch 6-8; (Z)-3 hingegen liefert stereoselektiv das δ-Lacton 5.  -  Das Epoxyketon 12 reagiert mit 9b zum (E,Z)-Säureester 13. (Z)-13 ergibt stereoselektiv das γ-Lacton 14.
    Type of Medium: Electronic Resource
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    Präparative Aspekte der aus β-Dicarbonylverbindungen synthetisierbaren 1,3-Dithiolane (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1158-1172 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparative Aspects of 1,3-Dithiolanes Synthesizable from β-Dicarbonyl CompoundsThe reaction of 1,2-ethanedithiol (1) with the β-dicarbonyl compounds 2 leads to the 1,3-dithiolanes 3 which are accessible to regioselective reactions at the free carbonyl function. Thus the derivatives of the β-keto acid esters can be hydrolyzed to give the corresponding carboxylic acids 4 which make the ester group modified 1,3-dithiolanes 3 accessible in good yields. Addition of trimethyloxonium tetrafluoroborate produces the monodithiolanium salts 6 which on hydrolysis rapidly decompose into 2 and the vinyl thioethers 8. Reaction of 3 with the Grignard reagents 10 yields the 2-(2-hydroxyalkyl)-1,3-dithiolanes 11. Dethioacetalization of 11 with HgO/BF3 leads to the β-hydroxy ketones 12. The retro reaction of 3 leads to the basic compounds 2 which, however, are obtained only in moderate yields.  -  Finally the performance of the sensitive silylenol ether 13 starting from 3g is described.
    Notes: Aus 1,2-Ethandithiol (1) und den β-Dicarbonylverbindungen 2 werden die 1,3-Dithiolane 3 erhalten, die regioselektiven Reaktionen an der noch freien Carbonylfunktion zugänglich sind. So lassen sich die Derivate der β-Ketocarbonsäureester zu den Carbonsäuren 4 hydrolysieren, die bei der Veresterung mit den Alkanolen 5 die estergruppenmodifizierten 1,3-Dithiolane 3 liefern. Einwirkung von Trimethyloxonium-tetrafluoroborat ergibt die Monodithiolaniumsalze 6, die bei der Hydrolyse rasch in 2 und die Vinylthioether 8 zerfallen. Umsetzung von 3 mit den Grignardreagenzien 10 ergibt die 2-(2-Hydroxyalkyl)-1,3-dithiolane 11. Dethioacetalisierung von 11 mit HgO/BF3 führt zu den β-Hydroxyketonen 12. Die Rückspaltung von 3 zu 2 gelingt nur in mäßigen Ausbeuten.  -  Schließlich wird noch die Darstellung des empfindlichen Silylenolethers 13 aus 3g beschrieben.
    Additional Material: 5 Tab.
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    Chemie und Stereochemie der Iridoide, IV. Synthese und Röntgenstrukturanalyse von 15-Methyl-12-epi-prostaglandin F2β (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 761-772 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry and Stereochemistry of Iridoids, IV. - Synthesis and X-Ray Structure Analysis of 15-Methyl-12-epi-prostaglandin F2βCrystalline(15R)- and (15S)-15-methyl-12-epi-PGF2β [15R)-5b and 5b] are synthesized enantiomerically pure starting from (1S,6R,9R)-(+)-7,9-bis(p-phenylbenzoyloxy)-3-oxabicyclo- [4.3.0]nonan-2-ol (1), which is prepared from catalpol. Contrary to our described synthesis of 12-epi-PGF2β, the intermediate products 2-5a are crystalline by virtue of the introduction of the p-phenylbenzoyl protecting group. Thus, their physical constants could be determined unequivocally. The X-ray structure analysis of (15R)-15-epi-PGF2β proves the correctness of our earlier statements based on analytical and spectroscopical investigations.
    Notes: Ausgehend von dem aus Catalpol hergestellten (1S,6R,7R,9R)-(+)-7,9-Bis(p-phenylbenzoyloxy)-3-oxabicyclo[4.3.0]nonan-2-ol (1) werden (15R)- und (15S)-15-Methyl-12-epi-PGF2β [(15R)-5b und 5b] kristallin und enantiomerenrein synthetisiert. Im Gegensatz zu der von uns beschriebenen Synthese von 12-epi-PGF2β sind durch die Einführung der p-Phenylbenzoyl-Schutzgruppen auch die Zwischenprodukte 2-5a kristallin, so daß ihre physikalischen Konstanten eindeutig bestimmt werden konnten. Die Röntgenstrukturanalyse von (15R)-15-Methyl-12-epi-PGF2β beweist, daß die von uns aus den analytischen und spektroskopischen Untersuchungen gemachten Aussagen richtig sind.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198419840412
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    Synthese und Reaktionen der 3-O-Phosphoniogluco-und -allofuranosen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1245-1260 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of 3-O-Phosphoniogluco- and AllofuranosesStarting from the bicyclic gluco- (3, 5, 7, and 9) and allofuranoses 11 the isolable 3-O-phosphonio-carbohydrates (4, 6, 8, 10, and 12) were synthesized by reaction with triphenylphosphane (1), diethyl azodicarboxylate (2), and alkylating or acylating agents. On heating, the various allo configurated salts 12 are converted into the corresponding at C-3 epimeric gluco configurated substitution products offering a wide range of flexibility. The reactions of the gluco configurated salts depend strongly on the type of nucleophile to be introduced and from neighboring groups in the carbohydrate skeleton. The iodide 4a and the azide 4g react by substitution forming the allo derivatives 15. In contrast, bromide, chloride, and sulfonate as gegen-ions mainly cause rearrangement of the 5,6-isopropylidene bridge or opening of the 5,6-anhydro structure.
    Notes: Aus den bicyclischen Gluco- (3, 5, 7 und 9) und Allofuranosen 11 werden mit Triphenylphosphan (1), Azodicarbonsäure-diethylester (2) und Alkylierungs- oder Acylierungsmitteln isolierbare 3-O-Phosphoniokohlenhydrate (4, 6, 8, 10 und 12) hergestellt. Durch Erwärmen der allo-konfigurierten Salze 12 können an C-3 epimere gluco-konfigurierte Substitutionsprodukte in großer Vielfalt gewonnen werden. Die Reaktionen der gluco-konfigurierten Salze werden stark vom Charakter des einzuführenden Nucleophils und von Nachbargruppen im Kohlenhydratgerüst beeinflußt. Während das Iodid 4a und das Azid 4g unter Substitution zum allo-Derivat 15 reagieren, tritt in den Fällen mit Bromid, Chlorid oder Sulfonat als Gegen-Ion Umlagerung von 5,6-Iso-propylidenbrücken bzw. öffnung von 5,6-Anhydrostrukturen ein.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219820703
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    Tetrapyrrol-Biosynthese, 14. Extrem selektive Porphyrin-Bildung bei der Cyclisierung verschiedener Oligopyrrole (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1272-1279 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tetrapyrrole Biosynthesis, 141).  -  Extremely Selective Porphyrin Formation by Cyclization of Different OligopyrrolesIn order to gain insight into the formation tendency of porphyrins, the acid catalysed condensation of the linear oligopyrroles 12-d, 18, and 19 was investigated in several combinations. Although the formation of cyclic tetra-, penta-, hexa-, and heptapyrroles might in principle be possible herewith, only cyclization to the porphyrin 13 under elimination of monopyrrole units took place in every case. This remarkable behaviour of the oligopyrroles is caused by their favoured helical conformation, which always forces their cyclization to the porphyrin system.
    Notes: Um Einblick in die Bildungstendenz der Porphyrine zu gewinnen, wurde die säurekatalysierte Kondensation linearer Oligopyrrole 12a-d, 18 und 19 in verschiedenen Kombinationen untersucht. Obwohl hierbei im Prinzip die Bildung cyclischer Tetra-, Penta-, Hexa- und Heptapyrrole möglich wäre, erfolgte in jedem Falle Cyclisierung zum Porphyrin 13 unter Eliminierung von Monopyrrol-Einheiten. Ursache für dieses bemerkenswerte Verhalten der Oligopyrrole ist deren begünstigte helikale Konformation, die stets den Ringschluß zum Porphyrin-Grundgerüst erzwingt.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219820705
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    Conformation of peptides containing α-Aminoisobutyric acid the crystal structure of Boc-Gly-l-Ala-Aib-OMe (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1322-1329 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Konformation von Peptiden mit α-Aminoisobuttersäure.  -  Die Kristallstruktur von Boc-Gly-L-Ala-Aib-OMeBoc-Gly-L-Ala-Aib-OMe (1) kristallisiert in der Raumgruppe P212121 mit a = 10.043(3), b = 11.590(5), c = 16.779(1) Å und Z = 4 (R-Faktor für 1859 symmetrieunabhängige Reflexe: 0.043). Das Tripeptid bildet über eine 4 → 1-intramolekulare Wasserstoffbrückenbindung einen “β-turn”-Typ III, obwohl das Cα-Atom im Aib-Rest nicht direkt an dem “β-turn”-Ringsystem beteiligt ist. Intermolekulare Wasserstoffbrücken verknüpfen die Einzelmoleküle schraubenförmig entlang [100].
    Notes: Boc-Gly-L-Ala-Aib-OMe (1) crystallizes in the space group P212121 with a = 10.043(3), b = 11.590(5), c = 16.779(1) Å, and Z = 4 (R value for 1859 symmetry independent reflexions: 0.043). On the basis of a 4 → 1 intramolecular hydrogen bond, the tripeptide forms a β-turn type III, although the Cα atom in the Aib residue is not directly involved in the β-turn ring system. Inter-molecular hydrogen bonds link the single molecules to helical structures along [100].
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198219820709
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    5,10-Überbrückte Pyrido [3,2-g]chinoline durch [4 + 2]-Cycloaddition von Dienophilen an Pyrido[3,2-g]chinoline (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 877-887 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 5,10-Bridged Pyrido[3,2-g]quinolines via [4+2] Cycloaddition of Dienophiles to Pyrido[3,2-g]quinolinesIn a Diels-Alder reaction, (E)-1,2-dichloroethene (5a), α-acetoxyacrylonitrile (5b), and maleic anhydride (8), respectively, add to the medium ring of some pyrido[3,2-g]quinolines to afford the 5,10-bridged pyrido[3,2-g]quinolines 6a - c, e, f, and 9a - c, respectively. The regioisomeric α-acetoxyacrylonitrile adducts of 4b arise in a ration of 6e:6f = 94.6. On hydrolysis of this mixture, only ketone 7 is obtained. The structures of all compounds are proven by their proton and carbon-13 spectra.
    Notes: (E)-1,2-Dichlorethen (5a), α-Acetoxyacrylnitril (5b) bzw. Maleinsäureanhydrid (8) addieren sich in einer Diels-Alder-Reaktion an den mittleren Ring einiger Pyrido[3,2-g]chinoline 4 zu den 5, 10-überbrückten Pyrido[3,2g]chinolinen 6a - c, e, f bzw. 9a - c. Die regioisomeren α-Acetoxyacrylnitril-Addukte von 4b entstehen dabei im Verhältnis 6e:6f = 94:6. Durch Hydrolyse erhält man daraus das einheitliche Keton 7. Die Strukturen aller Verbindungen wurden 1H- und 13C-NMR-spektroskopisch bewiesen.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198419840505
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    Chemie reaktiver Kationen von Schwefeldioxidanalogen, X. Umsetzung mit aromatischen Carbodiimiden - Darstellung von Benzothiadiazinen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 904-910 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Reactive Cations Derived from Sulfur Dioxide Analogues, X. - Reaction with Aromatic carbodiimides - Synthesis of BenzothiadiazinesDiphenyl- and bis(4-methoxyphenyl)carbodiimide react with N-methyl-N-sulfinylmethanaminium tetrafluoroborate (2) to give benzothiadiazine 1-oxides 3. The structure of the substituted compound 3a was determined, the course of the complex reaction is discussed.
    Notes: Diphenyl- und Bis(4-methoxyphenyl)carbodiimid reagieren mit N-Methyl-N-sulfinylmethanaminium-tetrafluoroborat (2) unter Bildung von Benzothiadiazin-1-oxiden 3. Die Struktur der substituierten Verbindung 3a wurde bestimmt, der Verlauf der komplexen Reaktion wird diskutiert.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198419840509
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    Synthesis of Peptides with α,β-Dehydroamino Acids, I. Synthesis of N-Benzyloxycarbonyl and N-Trifluoroacetyl Dipeptides of Dehydroalanine and Dehydrophenylalanine (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 920-928 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese von Peptiden mit α,β-Dehydroaminosäuren, I. - Synthese von N-(Benzyloxycarbonyl)-und N-(Trifluoracetyl) dipeptiden von Dehydroalanin und DehydrophenylalaninDie Kondensation von Nα-(Benzyloxycarbonyl)- und Nα-(Trifluoracetyl)aminosäureamiden mit Brenztrauben- und Phenylbrenztraubensäure in Gegenwart von p-Toluolsulfonsäure als Katalysator führt zu N-(Benzyloxycarbonyl)- und N-(Trifluoroacetyl)dehydrodipeptiden mit C-ständigem ΔAla bzw. ΔPhe (Tab 2 und 3).
    Notes: Condensation of amides of N-(benzyloxycarbonyl)- and N-(trifluoroacetyl)amino acid with pyruvic and phenylpyruvic acid yields, in the presence of p-toluenesulfonic acid as a catalyst, N-(benzyloxycarbonyl)- and N-(trifluoroacetyl)dehydro dipeptides with C-terminal Δ Ala and ΔPhe, respectively (Table 2 and 3).
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198419840511
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    Asymmetrische Synthesen über heterocyclische Zwischenstufen, XXIII. Studien zur enantioselektiven Synthese von α-Alkyl-α-(2-furyl)-glycinen durch Alkylieren von an C-6 chiral substituierten 3-(2-Furyl)-3,6-dihydro-2H-1,4-oxazin-2-onen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 939-950 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Synthesis via Heterocyclic Intermediates, XXIII. - Studies on the Enantioselective Synthesis of α-Alkyl-α-(2-furyl)glycines by Alkylation of 3-(2-furyl)-3,6-dihydro-2H-1,4-oxazin-2-ones chirally Substituted at C-63-(2-Furyl)-3,6-dihydro-2H-1,4-oxain-2-ones 10 and 11 are synthesized from DL-(2-furyl)glycine and 2-hydroxyalkanoic acids 4. The heterocycles 10 and 11 contain an endocyclic chiral center at C-6. Their potassium derivatives 12 (obtained with potassium tert-butoxide) react with alkyl halides R2 - X in good chemical yields and with d. e. values (d. e. = asymmetric induction) from 50 → 95% to give the adducts 13. These on hydrolysis are cleaved to yield α-alkyl-α-(2-furyl)-glycines 17 and 2-hydroxyalkanoic acids 4.
    Notes: Ausgehend von DL-(2-Furyl)glycin und den 2-Hydroxyalkansäuren 4 werden die 3-(2-Furyl)-3,6-dihydro-2H-1,4-oxazin-2-one 10 und 11 aufgebaut, die an C-6 ein endocyclisches Chiralitätszentrum besitzen. Deren Kaliumverbindungen 12 (erhalten mit Kalium-tert-butylat) reagieren mit Alkylhalogeniden R2 - X an C-3 mit guten chemischen Ausbeuten und mit 50 → 95% d.e.) (d.e. = asymmetrische Induktion). Der Alkylrest R2 tritt trans zu R1 (am induzierenden Zentrum) ein. Bei der Hydrolyse der Addukte 13 werden die 2-Hydroxyalkansäuren 4 und die (optisch aktiven) α-Alkyl-α-(2-furyl)glycine 17 freigesetzt.
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    Über die Herkunft von 3,6-Epoxyalkandisäuren im Humanurin (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1513-1518 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on the Origin of 3,6-Epoxyalkanedioic Acids in Human UrineThe 3,6-epoxyalkanedioic acids 1-4 recently found in human urine are obviously metabolic end products of so far unknown precursors produced in the body.
    Notes: Die im Humanurin kürzlich aufgefundenen 3,6-Epoxyalkandisäuren 1-4 sind offenbar Endabbauprodukte im Körper gebildeter bisher unbekannter Vorstufen.
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    URL: http://dx.doi.org/10.1002/jlac.198419840811
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    Reaktionen von Kohlenhydrat-Acetalen mit Organolithiumverbindungen. Synthese einer 3-Desoxy-α-D-erthro-hexofuranosid-2-ulose und 6-Desoxy-α-D-xylo-hexofuranos-5-ulose (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1543-1547 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Carbohydrate Acetals with Organolithium Compounds.  -  Synthesis of 3-Deoxy-α-D-erythro-hexofuranosid-2-ulose and 6-Deoxy-α-D-xylo-hexofuranos-5-uloseMethyl 2,3:5,6-di-O-isopropylidene-α-D-mannofuranoside (1) reacts with lithium diisopropylamide to give the methyl 3-deoxy-5,6-O-isopropylidene-α-D-erythro-hexofuranosid-2-ulose (2), while 1,2-O-isopropylidene-3,5,6-O-methylidyne-α-D-glucofuranose (3) yields 6-deoxy-1,2-O-isopropylidene-α-D-xylo-hexofuranos-5-ulose (4).
    Notes: Das Methyl-2,3:5,6-di-O-isopropyliden-α-D-mannofuranosid (1) reagiert mit Lithiumdiisopropylamid zur Methyl-3-desoxy-5,6-O-isopropyliden-α-D-erythro-hexofuranosid-2-ulose (2), während die 1,2-O-Isopropyliden-3,5,6-O-methylidin-α-D-glucofuranose (3) die 6-Desoxy-1,2-O-isopropyliden-α-D-xylo-hexofuranos-5-ulose (4) liefert.
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    URL: http://dx.doi.org/10.1002/jlac.198219820813
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    Synthesen mit α-metallierten Isocyaniden, LI. Diastereoselektive Synthese von Ethyl-(2S,3S,4R)- und -(2R,3R,4R)-2-amino-3,4,5-trihydroxypentanoat (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1548-1552 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with α-Metalated Isocyanides, LI.  -  Diastereoselective Synthesis of Ethyl (2S,3S,4R)- and (2R,3R,4R)-2-Amino-3,4,5-trihydroxypentanoateEthyl isocyanoacetate (1) reacts (base-induced) with 2,3-O-isopropylidene-D-glyceraldehyde (3) to give the two diastereomeric 5-(4-dioxolanyl)-2-oxazoline-4-carboxylic acid esters 4 and 5 with trans configuration at the oxazoline ring. Acid hydrolysis of 4 or 5 gives the title compounds 6a and 7a which were characterized as their tetraacetates 6b and 7b.  -  Analogously, 2,3-O-isopropylidene-D-erythrose (10) gives with 1 the two diastereomeric trans-2-oxazoline-4-carboxylic acid esters 11 and 12.
    Notes: Isocyanessigsäure-ethylester (1) reagiert (baseninduziert) mit 2,3-O-Isopropyliden-D-glycerin-aldehyd (3) zu den beiden 5-(4-Dioxolanyl)-2-oxazolin-4-carbonsäure-ethylestern 4 und 5 mit trans-Konfiguration am Oxazolinring, d. h. die Konfiguration an C-4 paßt sich jeweils der an C-5 an. Saure Hydrolyse von 4 oder 5 liefert die Titelverbindungen 6a und 7a, die als Tetraacetate 6b und 7b charakterisiert wurden.  -  2,3-O-Isopropyliden-D-erythrose (10) reagiert analog mit 1 zu den beiden diastereomeren trans-2-Oxazolin-4-carbonestern 11 und 12.
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    Masthead (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984) 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419840601
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    Metalloporphyrins in Polymeric Matrices, Micelles, and Vesicles, VI. Hydrophobic and Hydrophilic Derivatives of 3,8-Diformyl-deuteroporphyrin Dimethyl Ester and their Interaction with Vesicles (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1057-1067 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalloporphyrine in polymeren Matrizen. Mizellen und Vesikeln, VI. - Hydrophobe und hydrophile Derivate des 3,8-Diformyldeuteroporphyrin-dimethylesters und ihre Wechselwirkung mit Vesikeln3,8-Diformyldeuteroporphyrin-dimethylester (1a) wurde durch Ozonisierung des diprotonierten Dikations von Protoporphyrin-dimethylester 1b erhalten. Mehrere Derivate wurden dargestellt, die entweder hydrophobe Eigenschaften aufweisen oder hydrophile Substituenten in der “nördlichen Hemisphäre” des Porphyrinliganden oder an beiden Seiten tragen. Die Porphyrine wurden in wäßrigen Medien gelöst, die Vesikel mit elektroneutralen, -negativen oder -positiven Oberflächenladungen enthielten. Der Aufenthaltsort der gelösten Porphyrine wurde durch den spektroskopischen Nachweis von Reaktionen der zentralen Porphyrin-Stickstoffatome oder von peripheren Substituenten mit wasserlöslichen Säuren oder Metall-Ionen bestimmt.
    Notes: 3,8-Diformyldeuteroporphyrin dimethyl ester (1a) was obtained by ozonization of the diprotonated dication of protoporphyrin dimethyl ester 1b. Several derivatives have been prepared, which are either hydrophobic, or bear hydrophilic substituents in the „northern hemisphere“ of the porphyrin ligand or on both sides. The porphyrins have then been dissolved in aqueous media containing vesicles with electroneutral, -negative, or -positive surface charges. The localization of the dissolved porphyrin chromophore was determined spectroscopically following reactions of the central porphyrin nitrogen atoms or of peripheral substituents with water-soluble acids or metal ions.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198419840602
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    Synthese der N-terminalen Aminosäure der Nikkomycine I, J, X und Z (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1615-1622 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the N-Terminal Amino Acid of the Nikkomycins I, J, X, and ZA mixture of four stereoisomers of 2-amino-4-hydroxy-4-(5-hydroxy-2-pyridyl)-3-methylbutanoic acid (14), the N-terminal amino acid of the nikkomycin antibiotics could be synthesized in a twelve-step procedure. By comparison of 1H NMR spectra, mass spectra and of the gas chromato-graphic behaviour of various derivatives the constitution and relative configuration of the natural compound has been confirmed.
    Notes: Ein Gemisch aus vier Stereoisomeren von 2-Amino-4-hydroxy-4-(5-hydroxy-2-pyridyl)-3-methylbuttersäure (14) der N-terminalen Aminosäure der Nikkomycin-Antibiotika konnte in einer zwölfstufigen Synthese dargestellt werden. Durch Vergleich der 1H-NMR-Spektren, Massenspektren und des gaschromatographischen Verhaltens verschiedener Derivate von Synthese- und Naturprodukt wird die Richtigkeit der angenommenen Konstitution und relativen Konfiguration bestätigt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jlac.198219820904
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    Neue 4-Chinolinol- und 5,6,7,8-Tetrahydro-4-chinolinol-abkömmlinge mit biozider Wirkung (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1656-1676 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New 4-Quinolinol- and 5,6,7,8-Tetrahydro-4-quinolinol Derivatives with Biocidal EffectThe synthesis of some O-substituted 4-quinolinols and 5,6,7,8-tetrahydro-4-quinolinols 7-13 is described. 2 and 4 afford the 4-chloroquinolines 14 and 15 with POCI3. These can be transformed into 4-aryloxyquinolines 16 and 17 as well as 4-alkyl- or -arylthioquinolines 20 and 4-aminoquinolines 21.
    Notes: Es wird die Synthese einiger O-substituierter 4-Chinolinole und 5,6,7,8-Tetrahydro-4-chinolinole 7-13 beschrieben. Ausgehend von 2 und 4 gelangt man mit POCl3 zu 4-Chlorchinolinen 14 und 15, welche in die 4-Aryloxychinoline 16 und 17 sowie 4-Alkyl-(Aryl-)thiochinoline 20 bzw. 4-Aminochinoline 21 übergeführt werden.
    Additional Material: 8 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219820908
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  • 77
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    Synthese des α-Anomeren von ara-7-Desazaguanosin durch Phasentransferglycosylierung  -  Steuerung des Anomerenverhältnisses durch das quartäre Ammoniumsalz (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1634-1642 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the α-Anomer of ara-7-Deazaguanosine via Phase-Transfer Glycosylation  -  Control of Anomer Formation by the Quaternary Ammonium Salt2-Amino-7-(α-D-arabinofuranosyl)-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-on (1), the α-anomer of ara-7-deazaguanosine (2), has been prepared via phase-transfer glycosylation of 4-methoxy-2-methylthio-7H-pyrrolo[2,3-d]pyrimidine (3) with 2,3,5-tri-O-benzyl-1-bromoarabinofuranose (5a/5b). The anomeric control can be achieved by equilibration of the α-halogenose 5a to its β-anomer 5b in the presence of a quaternary ammonium salt. The more reactive 5b results in a preferred α-nucleoside formation of 6b by a SN2-type displacement reaction. Treatment with acid causes ether cleavage of 6b under formation of 7a, subsequent methoxymethylation yields 7b. The methylthio group of 7b was displaced by an acetamino residue by nucleophilic substitution in a molten acetamide/sodium hydride mixture giving 7c. After deacetylation simultaneous removal of the methoxymethyl and benzyl residues took place by treatment of 7d with boron trichloride at - 78°C yielding the crystalline α-nucleoside 1.
    Notes: 2-Amino-7-(α-D-arabinofuranosyl)-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-on (1), das α-Anomer von ara-7-Desazaguanosin (2), wurde durch Phasentransferglycosylierung von 4-Methoxy-2-methylthio-7 H-pyrrolo[2,3-d]pyrimidin (3) mit 2,3,5-Tri-O-benzyl-1-bromarabinofuranose (5a/5b) dargestellt. Eine Anomerensteuerung kann über die äquilibrierung der α-Halogenose 5a zur β-Verbindung 5b durch das quartäre Ammoniumsalz erreicht werden. Das reaktivere 5b führt dann in einem SN2-Mechanismus bevorzugt zum α-Nucleosid 6b. Säurehydrolyse führt zur Etherspaltung bei 6b unter Bildung von 7a; anschließende Methoxymethylierung gibt 7b. Nucleophile Substitution des Methylthiorestes in einer Natriumhydrid/Acetamidschmelze führt zu 7c, das zu 7d deacetyliert wird. Simultane Abspaltung der Methoxymethylgruppe und der Benzylreste mit Bortrichlorid bei  -  78°C führt zum kristallinen α-Nucleosid 1.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219820906
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  • 78
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    Eine weitere Synthese von (±)-Lycopodin (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1700-1705 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Further Synthesis of (±)-LycopodinThe synthesis of (±)-lycopodin from 2-cyanoethyl-5-methyl-1,3-cyclohexanedione (2b) in six steps is described. An important step is the stereoselective 1,3-annulation reaction of the unsaturated imine 4b with acetone dicarboxylic acid yielding the tricyclic ketone 5b.
    Notes: Die Synthese von (±)-Lycopodin (1) aus 2-Cyanethyl-5-methyl-1,3-cylohexandion (2b) in sechs Stufen wird beschrieben. Ein wichtiger Syntheseschritt ist die stereoselektive 1,3-Anellierung des ungesättigten Imins 4b mit Acetondicarbonsäure zum tricyclischen Keton 5b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820910
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  • 79
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    Pilzpigmente, 41. Naphthochinon-Farbstoffe aus den Schleimpilzen Trichia floriformis und Metatrichia vesparium (Myxomycetes) (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1722-1729 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fungus Pigments, 4141).  -  Naphthoquinone Pigments from the Slime Moulds Trichia floriformis and Metatrichia vesparium (Myxomycetes)Trichione (1) is the red main pigment of fruiting bodies from the slime mould Trichia floriformis. It contains a 2,5-dihydroxynaphthoquinone chromophore, substituted in position 3 by an unsaturated side chain carrying a terminal hemimalonate moiety. Homotrichione (7) differs by the presence of two additional CH2 groups in the side chain. It co-occurs with arcyriaflavin B (5), arcyriaflavin C (6) and further pigments in Metatrichia vesparium.
    Notes: Die Fruchtkörper des Schleimpilzes Trichia floriformis enthalten als roten Hauptfarbstoff Trichion (1), ein 2,5-Dihydroxynaphthochinon, das in 3-Stellung eine ungesättigte Seitenkette mit terminaler Malonhalbester-Gruppierung trägt. Homotrichion (7) unterscheidet sich nur durch eine um zwei CH2-Gruppen längere Seitenkette. Es kommt neben 1, Arcyriaflavin B und C (5 bzw. 6) und weiteren Farbstoffen in Metatrichia vesparium vor.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219820913
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  • 80
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    Retinoide und Carotinoide, II Synthese von (13Z)-Retinoidsäuren (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1740-1745 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Retinoids and Carotenoids, II. - Synthesis of (13Z)-Retinoic AcidsPhosphonium ylides 3 react with (E)-2-methyl-3-(4-methyl-2-oxo-2H-pyran-6-yl)propenal (2) to give 2-pyrone derivatives 4 which undergo ring opening by treatment with sodium tetrahydroborate/potassium hydroxide/methanol affording (13Z)-retinoic acids.
    Notes: Phosphoniumylide 3 reagieren mit (E)-2-Methyl-3-(4-methyl-2-oxo-2H-pyran-6-yl)propenal (2) zu 2-Pyronderivaten 4, bei deren Reduktion mit Natrium-tetrahydroborat/Kaliumhydroxid/Methanol unter Ringöffnung (13Z)-Retinoidsäuren 5 entstehen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419841014
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    Masthead (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984) 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419841101
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  • 82
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    Pyrane, 100. 5,6-Dihydro-2H-pyran-3(4H)-on als Baustein zur Synthese pyrananellierter Heterocyclen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1759-1777 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pyrans, 100.  -  5,6-Dihydro-2H-pyran-3(4H)-one as a Building Unit for the Synthesis of Pyran-annulated Heterocyclic CompoundsOnly in a few cases 5,6-dihydro-2H-pyran-3(4H-one (3) reacts regioselectively with ortho-substituted phenylcarbonyl compounds to form pyran-annulated heterocyclic compounds like the pyrano[3,2-b]quinoline 7c. Better results are obtained in reactions involving the enamine 15d derived from 3, the silyl enol ether 18 and the lithium enolate 14 derived from 18. These pyran derivatives with 2,3- or 3,4-double bonds are well suited for successful synthesis of 2- or 4-substituted 3-pyranones such as 2, 21a, 21b, 23a-c, 26a-c, 31a-c, 32, and 35a-c. They also allow to synthesize pyrano[3,2-b]- or -[3,4-b]quinolones, -chromones, and -thiochromones 6a, 30a-c, 38a-d.
    Notes: Während 5,6-Dihydro-2H-pyran-3(4H)-on (3) sich mit ortho-substituierten Phenylcarbonylverbindungen nur in Einzelfällen regioselektiv zu pyrananellierten Heterocyclen umsetzt - z. B. zum Pyrano[2,3-b]chinolin 7c -, gelingt das besser mit dem aus 3 hergestellten Enamin 15d, dem Silylenolether 18 und dem daraus gewonnenen Lithiumenolat 14. Diese Pyranderivate mit 2,3-oder 3,4-Doppelbindungen eignen sich zur gezielten Darstellung von 2- oder 4-substituierten 3-Pyranonen - z.B. 2, 21a, 21b, 23a-c, 26a-c, 31a-c, 32, sowie 35a-c - und von Pyrano[3,2-b]- oder -[3,4-b]chinolinen, -chinolonen, -chromonen und -thiochromonen 6a, 30a-c und 38a-d.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198419841102
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  • 83
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    Synthese weiterer Eremophilan-Derivate (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1785-1790 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Further Eremophilane DerivativesStarting with suitable octalin derivatives two further eremophilane derivatives (9 and 13) isolated from Euryops species were synthesized via the epoxides 5 and 6 by regiospecific ring opening with isopropenylmagnesium bromide in the presence of copper(I) iodide followed by appropriate transformation of the eremophilanes obtained. While the preparation of the racemic ketone 9 caused no problems, the corresponding 2α-hydroxy derivative in the trans-decalin series could not be obtained in satisfactory yields. The configurations of the natural compounds have now finally been elucidated.
    Notes: Ausgehend von geeigneten Octalin-Derivaten werden zwei aus Euryops-Arten isolierte Eremophilan-Derivate (9 und 13) über die Epoxide 5 und 6 durch regiospezifische Ringöffnung mit Isopropenylmagnesiumbromid in Gegenwart von Kupfer(I)-iodid und entsprechende Umwandlung der erhaltenen Eremophilane synthetisiert. Während die Darstellung des racemischen Ketons 9 keine Probleme bereitet, konnte das entsprechende 2α-Hydroxy-Derivat in der trans-Decalin-Reihe nicht in befriedigenden Ausbeuten erhalten werden. Die Konfigurationen der Naturstoffe sind damit endgültig geklärt.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198419841104
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  • 84
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    Stereochemische Untersuchungen zur Bildung von Naphtho-[1,2-b]furan-2-onen durch Hydrolyse von α,β-ungesättigten γ, Δ-Epoxysäureestern (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1781-1807 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemical Investigations on the Formation of Naphtho[1,2-b]furan-2-ones by Hydrolysis of α,β-Unsaturated γ,Δ-Epoxy Acid EstersThe α,β-unsaturated epoxy acid esters (E, Z)-12, -13, -30, -35a, and -42 are prepared from the epoxydecalones 8, 9, 25c, 29, and 34 by reaction with methyl (dimethoxyphosphoryl)acetate (14a). The (Z)-acid esters 12, 30, 35a, and 42, separated by column chromatography, give with 2 N H2SO4 in acetone the stereochemically pure naphthofuranones 15, 32, 36, and 43. As expected, hydrolysis of the (E)-acid esters 12, 30, and 35a yields the trans-dihydoxy acid esters 47-49.  -  Hydrolysis of (E, Z)-13 proceeds without stereoselectivity to give the butenolides 19 and 20, and the diol esters (E)-21 and -22.  -  The epoxy (E, Z)-acid esters 12 and 35a are homogeneously hydrogenated to the saturated, epimeric esters 18α/β and 41α/β which are hydolyzed to give the stereoisomeric hydroxylactones 16, 17 and 33, 40. On the other hand, 17, 33, and 40 are also obtained by hydrogenation of the butenolides 15, 32, and 37.
    Notes: Aus den Epoxydecalonen 8, 9, 25c, 29 und 34 werden mit Methyl-(dimethoxyphosphoryl)acetat (14a) die α,β-ungesättigten γ,Δ-Epoxysäureester (E, Z)-12, -13, -30, -35a und -42 dargestellt. Mit 2 N H2SO4 in Aceton werden aus den säulenchromatographisch abgetrennten (Z)-Säureestern 12 30, 35a und 42 die stereochemisch einheitlichen Naphthofuranone 15, 32, 36 und 43 erhalten. Die Hydrolyse der (E)-Säureester 12, 30 und 35a ergibt wie erwartet die trans-Dihydroxysäureester 47-49.  -  Die Hydrolyse von (E, Z)-13 verläuft ohne Stereoselektivität zu den Butenoliden 19 und 20 und den Diol-estern (E)-21 und -22.  -  Die (E, Z)-Epoxysäureester 12 und 35a können zu den gesättigten epimeren Estern 18α/β und 41α/β hydriert werden, deren saure Hydrolyse je zwei stereoisomere Hydroxylactone 16, 17 und 33, 40 liefert. Andererseits können 17, 33 und 40 auch aus den Butenoliden 15, 32 und 37 durch Hydrierung gewonnen werden.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219821005
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  • 85
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    Synthesen biskationischer, trypanocider 1-Benzofuran-Verbindungen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1836-1869 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Biscationic, Trypanocidal 1-Benzofuran Compounds2-Phenyl-1-benzofurans with the substituents Br, NO2, CN, and -NH2, -NH-C(=NH)-NH2, -C(=NH)-NH2, -C=N-CH2-CH2-NH in 4′,5-position were synthesized.  -  For arylated formamidine derivatives [Ar-N=CH-N(CH3)2] a simple new preparation was found by reacting amine hydrochlorides with dimethylformamide in the presence of cyanamide.  -  Based on 5- or 6-cyano-1-benzofuran-2-carboxylates a series of α,ω-bis(1-benzofuran-2-yl) derivatives with cyano-, amidino-, or imidazolinyl groups in 5- or 6-position was prepared.
    Notes: 2-Phenyl-1-benzofurane mit den Substituenten Br, NO2 sowie CN und -NH2, -NH-C(=NH)-NH2, -C(=NH)-NH2 sowie -C=N-CH2-CH2-NH in 4′,5-Stellung wurden synthetisiert.  -  Für arylierte Formamidin-Derivate [Ar-N=CH-(CH3)2] fand sich in der Umsetzung von Aminhydrochloriden mit Dimethylformamid in Gegenwart von Cyanamid ein einfaches, neues Herstellungsverfahren.  -  Auf der Basis von 5- oder 6-Cyan-1-benzofuran-2-carbonsäureester konnte eine Serie von α,ω-Bis(1-benzofuran-2-yl)-Derivaten mit Cyan- oder Amidino- oder Imidazolinyl-Gruppen in 5- oder 6-Stellung dargestellt werden.
    Additional Material: 4 Tab.
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    Enhydrazine, 32. Ein Zugang zu 3-Hydroxymethyl-1,5,6,7-tetrahydro-4H-indazol-4-onen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1891-1896 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enehydrazines, 32.  -  An Access to 3-Hydroxymethyl-1,5,6,7-tetrahydro-4H-indazol-4-ones5-Methyl-1,3-cyclohexanedione is C-acylated with benzyloxyacetimidazolide to yield 2b which with hydrazines gives the 1,5,6,7-tetrahydro-4H-indazol-4-ones 3a-d. Hydrogenolysis leads to the title compounds 4a-d. The acetate 5a from 3d is hydrogenolyzed to give 5b and is further transformed into the carbamate 6.
    Notes: 5-Methyl-1,3-cyclohexandion wird von Benzyloxyessigsäure-imidazolid zu 2b C-acyliert, das mit Hydrazinen die 1,5,6,7-Tetrahydro-4H-indazol-4-one 3a-d ergibt. Deren Hydrogenolyse führt zu den Titelverbindungen 4a-d. Das Acetat 5a aus 3d wird zu 5b hydrogenolysiert und weiter in das Carbamat 6 umgewandelt.
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  • 87
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    Partialsynthese des “Sargasterols” und des (20S)-Cholesterols (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1897-1906 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Partial Synthesis of “Sargastero” and (20S)-CholesterolThe data of the synthetic (20S)-3β-hydroxy-5-cholesten-24-one (5b) and its acetate 5a differ significantly from those given for the degradation product of “Sargastero”. The compounds 5a, b were converted into the E, Z-isomeric (20S)-stigmasta-5,24(28)-dien-3β-ols 8b, 9b, into their acetates 8a, 9a, and into (20S)-cholesterol (10b). (20S)-cholesterol acetate (10a) shows a lower melting point than that which is given in literature.
    Notes: Die Eigenschaften des synthetischen (20S)-3β-Hydroxy-5-cholesten-24-ons (5b) und seines Acetats 5a unterscheiden sich signifikant von den für das Abbauprodukt des “Sargasterols” beschriebenen. Aus 5a, b wurden die E, Z-isomeren (20S)-Stigmasta-5,24(28)-dien-3β-ole 8b, 9b und ihre Acetate 8a, 9a sowie das (20S)-Cholesterol (10b) dargestellt. (20S)-Cholesterolacetat (10a) zeigt einen tieferen Schmelzpunkt als in der Literatur angegeben.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/jlac.198219821011
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    Darstellung von 4,6-Diaminozuckern aus Hex-2-enosen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1920-1923 
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    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of 4,6-Diamino Sugars via Hex-2-enonesThe synthesis and structure determination of 4,6-diaminohexoses from glycals via 2-eno sugars, SN reaction with NaN3, and final reduction is described.
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    URL: http://dx.doi.org/10.1002/jlac.198219821013
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  • 89
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    Masthead (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982) 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821101
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  • 90
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    4-Amino-7-(rac-2,3-dihydroxypropyl)-7H-pyrrolo′l2,3-d]-pyrimidin  -  Synthese von Acyclotubercidin (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1940-1945 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 4-Amino-7-(rac-2,3-dihydroxypropyl)-7H-pyrrolo[2,3-d]pyrimidine  -  Synthesis of AcyclotubercidinAlkylation of the aglycone 4a with the tosylate 5b under phase transfer conditions in the presence of tetrabutylammonium hydrogen sulfate yields regioselectively the N-7 derivative 6a. Using benzyltriethylammonium chloride instead of the tetrabutylammonium salt as phase transfer catalyst the benzyl group of the catalyst is transferred to N-7 of the heterocycle 4a. After desulfurization and removal of the isopropylidene protecting group compound 3b was obtained. The latter represents an isosteric analogue of the antivirally active acyclonucleoside 2.
    Notes: Durch Phasentransfer-Alkylierung des Aglycons 4a mit dem Tosylat 5b in Gegenwart von Tetrabutylammoniumhydrogensulfat kann regioselektiv das N-7-Verknüpfungsprodukt 6a dargestellt werden. Wird die Reaktion in Gegenwart von Benzyltriethylammoniumchlorid als Phasentransfer-Katalysator durchgeführt, so erfolgt die übertragung des Benzylrestes vom Katalysator auf N-7 des Heterocyclus 4a. Das geschützte Acyclonucleosid 6a kann nach Entschwefeln und Abspalten der Isopropyliden-Schutzgruppe in 3b übergeführt werden. Verbindung 3b stellt ein Isoster des antiviral wirksamen Acyclonucleosids 2 dar.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821103
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  • 91
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    Asymmetrische Synthesen über heterocyclische Zwischenstufen, XVI. Enantioselektive Synthese von α-Alkyl-α-phenylglycinen durch Alkylieren von an C-6 chiral substituierten 3,6-Dihydro-3-phenyl-2H-1,4-oxazin-2-onen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1952-1970 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Syntheses via Heterocyclic Intermediates, XVI1).  -  Enantioselective Synthesis of α-Alkyl-α-phenylglycines by Alkylation of 3,6-Dihydro-3-phenyl-2H-1,4-oxazin-2-ones Chirally Substituted at C-63,6-Dihydro-3-phenyl-2H-1,4-oxazin-2-ones 3 are synthesized from DL-phenylglycine and (S)-2-hydroxyalkanoic acids 4. The heterocycles 3 contain an endocyclic chiral center at C-6. The anions 10 of 3 react with alkyl halides in good chemical yields and with d. e. values from 50 up to more than 95% (asymmetric induction) to give the adducts 11. On hydrolysis of 11 the 2-hydroxy-alkanoic acids 4 and the optically active (S)-α-alkyl-α-phenylglycines 14 are liberated.
    Notes: Ausgehend von DL-Phenylglycin und (S)-2-Hydroxyalkansäuren 4 werden die 3,6-Dihydro-3-phenyl-2H-1,4-oxazin-2-one 3 aufgebaut, die an C-6 ein endocyclisches Chiralitätszentrum besitzen. Die Anionen 10 von 3 reagieren mit Alkylhalogeniden an C-3 mit guten chemischen Ausbeuten und mit 50 bis mehr als 95% d. e. (asymmetrische Induktion). Bei der Hydrolyse der Addukte 11 werden die 2-Hydroxyalkansäuren 4 und die optisch aktiven (S)-α-Alkyl-α-phenylglycine 14 freigesetzt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821105
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  • 92
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    Optical resolution of racemic S-(Carboxymethyl)cysteine (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1995-1998 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Racematspaltung von S-(Carboxymethyl)cysteinRacemisches S-(Carboxymethyl)cystein [(R, S)-2] wird in das Ammoniumsalz (R, S)-3 übergeführt, das nach Herstellung einer übersättigten Lösung und Animpfen mit (R)- oder (S)-3 durch fraktionierende Kristallisation gespalten werden kann. (R, S)-2 bildet mit optisch aktiven Aminen diastereomere Salze, die leicht trennbar sind und so ebenfalls eine Racematspaltung erlauben. So erhält man mit (1R,2S)-2-Amino-1-phenyl-1-propanol (4) optisch reines (R)-S-(Carboxymethyl)-cystein [(R)-2] in 93proz. Ausbeute. Die Racematspaltung von (R, S)-2 ist auch mit Hilfe von (R)-1-Phenylethylamin (5) möglich.
    Notes: Racemic S-(carboxymethyl)cysteine [(R, S)-2] obtained from racemic cysteine is resolved via its ammonium salt (R, S)-3 by preferential crystallization procedure. Furthermore, (R, S)-2 forms with optically active amines separable, diastereomeric salts. Thus, (1R,2S)-2-amino-1-phenyl-1-propanol (4) affords optically pure (R)-S-(carboxymethyl)cysteine [(R)-2] in 93% yield. The resolution of (R, S)-2 is also possible with (R)-1-phenylethylamine (5).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821108
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  • 93
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    Asymmetrische Totalsynthese von 19-Nor-Steroiden mit photochemischer Schlüsselreaktion: Enantiomerenreine Zielverbindungen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1999-2040 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Total Synthesis of 19-Nor-Steroids via a Photochemical Key Reaction: Enantiomerically Pure Target CompoundsA total synthesis of the enantiomerically pure 19-nor-steroids estrone (1a), 19-norandrost-4-en-3,17-dione (2a), estradiol-17β (3a), and 19-nortestosterone (4a) is described. It follows the A + D→AD→ABCD sequence, proceeds via a kinetically unstable o-quinodimethane derivative obtained in a light induced reaction, and employs the chiral synthetic building block dimethyl (R)-2-vinyl-1,1-cyclopropanedicarboxylate (12b). The latter is easily accessible by an asymmetry inducing ScN′ reaction. During the synthetic procedure it is isolated enantiomerically pure. The analytic procedure reveals that 12b is formed with an optical purity or an enantiomeric excess, respectively, of 95%.
    Notes: Eine Totalsynthese der enantiomerenreinen 19-Nor-Steroide Östron (1a), 19-Norandrost-4-en-3,17-dion (2a), östradiol-17β (3a) und 19-Nortestosteron (4a) wird beschrieben. Sie folgt dem A + D→AD→ABCD-Aufbauprinzip, durchläuft ein lichtinduziertes, kinetisch instabiles o-Chinodimethan-Derivat und verwendet den chiralen Synthesebaustein (R)-2-Vinyl-1,1-cyclopropan-dicarbonsäure-dimethylester (12b). 12b ist durch eine Asymmetrie induzierende ScN′-Reaktion (s. Abb. 2) bequem zugänglich. Bei der Synthese fällt 12b enantiomerenrein an. Das analytische Procedere offenbart, daß 12b mit einer optischen Reinheit oder mit einem Enantiomeren-überschuß jeweils von 95% zustande kommt.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821109
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  • 94
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    Oniumsalz-katalysierte Acylierungen mit Diketen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2062-2067 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Onium Salt-catalyzed Acylations with DiketeneWeak NH- and CH-acids can be acylated advantageously by diketene (1) in the presence of a quaternary ammonium chloride. Carboxamides yield with one or two moles of 1 the products 3 or 10 selectively. β-Keto esters and β-diketones lead to 12a, b or 13, respectively, and acetoacetamides give 5 or 8. The polymer 16 and/or 17 is formed by self-condensation of 1.
    Notes: Schwache NH- und CH-Säuren können mit Diketen (1) vorteilhaft in Gegenwart eines quartären Ammoniumchlorids acyliert werden. Carbonsäureamide liefern wahlweise mit einem oder zwei Mol 1 die Produkte 3 bzw. 10. β-Ketoester und β-Diketone ergeben 12a, b bzw. 13, Amide der Acetessigsäure führen zu 5 oder 8. Bei der Selbstkondensation von 1 entstehen das Polymer 16 und/oder 17.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821112
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  • 95
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    Synthese des Lycopodium-Alkaloids (±)-Acetylflabellidin über 1,3-Anellierung von Eniminen (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2057-2061 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the Lycopodium Alkaloid (±)-Acetylflabellidine via 1,3-Annulation Reactions of EniminesThe 1,3-annulation reaction of 2,3,4,5-tetrahydro-6-methylpyridine (11) with the enimine 7 catalyzed by perchloric acid and subsequent acetylation stereoselectively yield the tetracyclic adduct 2 as the main product, the structure and relative configuration of which are in agreement with the acetyl derivative of the Lycopodium alkaloid flabellidine (1).
    Notes: Die durch Perchlorsäure katalysierte 1,3-Anellierung von 2,3,4,5-Tetrahydro-6-methylpyridin (11) an das Enimin 7 mit anschließender Acetylierung liefert in stereoselektiver Reaktion als Hauptprodukt das tetracyclische Addukt 2, dessen Struktur und relative Konfiguration mit dem Acetylderivat des Lycopodium-Alkaloids Flabellidin (1) identisch ist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821111
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  • 96
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    Synthese sterisch gehinderter Peptide und Depsipeptide nach einem Säurechlorid-Verfahren mit 2-Phosphonioethoxycarbonyl-(Peoc-)Aminosäuren und -Hydroxysäuren (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2068-2078 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Sterically Hindered Peptides and Depsipeptides by Means of an Acid Chloride Procedure with 2-Phosphonioethoxycarbonyl (Peoc) Amino Acids and Hydroxy Acids2-(Triphenylphosphonio)ethoxycarbonyl (Peoc) amino acids 1 and hydroxy acids 5 are converted by treatment with oxalyl chloride into the corresponding acid chlorides 2 and 6 which are stable at room temperature. Sterically hindered amide bonds, for instance the blocked valine peptides 3a - g and hydroxyacyl dipeptides 7, can be synthesized using these activated compounds. In this manner sporidesmolic acid B (9a) is obtained from its fully protected form 7a; the former being identical in its properties with the degradation product of sporidesmolide I. In this procedure no razemisation takes place although the acid chloride condensation was applied twice in succession.
    Notes: 2-(Triphenylphosphonio)ethoxycarbonyl-(Peoc-)aminosäuren 1 und -hydroxysäuren 5 werden mit Oxalylchlorid in bei Raumtemp. stabile Säurechloride 2 bzw. 6 übergeführt. Mit diesen aktivierten Verbindungen werden sterisch gehinderte Amidbindungen  -  z. B. in den geschützten Valin-Peptiden 3a - g und in Hydroxyacyl-Dipeptiden 7  -  hergestellt. Nach Schutzgruppenabspaltung aus der voll geschützten Form 7a entsteht so die Sporidesmolsäure B (9a), die in ihren Eigenschaften mit dem Abbauprodukt aus dem Sporidesmolid I übereinstimmt. Trotz zweimaliger Anwendung der Säurechlorid-Kondensation ist keine Racemisierung eingetreten.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821113
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  • 97
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    Synthese von 5H,5′H-5,5′-(2-Buten-1,4-diyliden)bis[furan-2-on] (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2096-2097 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 5H,5′H-5,5′-(2-Buten-1,4-diyliden)bis[furan-2-one]Reaction of 2,5-dihydro-2,5-dimethoxyfuran with trimethylchlorsilane affords cis-5H,5′H-5,5′-(2-buten-1,4-diyliden)bis[furan-2-one] (2)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821118
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  • 98
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    Syntheses of 3-Cyanopropan- and 4-Aminobutanamides (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2098-2102 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesen von 3-Cyanpropan- und 4-AminobutanamidenDie 3-Cyanpropanamide 5a - g werden aus Propenamiden und Blausäure oder aus 3-Cyanpropanoylverbindungen nach den Methoden A - D dargestellt. Hydrierung von 5a - d, g liefert die 4-Aminobutanamide 2a - d, g.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821119
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    Masthead (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982) 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821201
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  • 100
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    1,3-Dipolare Cycloadditionen von Azomethin-yliden (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2146-2152 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions of Azomethine Ylides1,3-Dipolar cycloadditions of the azomethine ylides 2 and 9 with Schiff′s bases have been investigated. Depending on the structures of both the dipolarophiles and the dipoles, cycloadducts of “exo” and/or “endo” type were formed.
    Notes: Die 1,3-dipolaren Cycloadditionen der Azomethin-ylide 2 und 9 mit Schiffschen Basen wurden untersucht. Es bilden sich Cycloaddukte vom “exo”-und/oder “endo”-Typ in Abhängigkeit von der Struktur des Dipolarophils und des Dipols.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821205
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