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  • General Chemistry  (11,858)
  • Organic Chemistry  (7,898)
  • Cell & Developmental Biology  (2,554)
  • 1975-1979  (9,203)
  • 1970-1974  (9,115)
  • 1910-1914
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 153-162 
    ISSN: 0148-7280
    Keywords: spermatozoa ; cell surface ; epididymis ; surface labeling ; gel electrophoresis ; proteins ; membrane ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Differences in the exposure of spermatozoa surface components during epididymal passage have been examined using lactoperoxidase-catalyzed 125I-iodination or labeling with 125I-diazodiiodosulfanilic acid. Labeled surface proteins obtained from caput and cauda epididymides were solubilized in detergent, separated by sodium dodecylsulfate polyacrylamide slab gel electrophoresis, and identified by radiography. Densitometer scans of autoradiograms revealed increased amounts or exposures of surface proteins of ∼35,000, ∼39,000, ∼50,000, and ∼78,000 molecular weight on the cauda epididymal spermatozoa.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 177-185 
    ISSN: 0148-7280
    Keywords: multiple enzyme forms ; acid nitrophenyl phosphatase ; sea urchin ; development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Acid nitrophenyl phosphatases from sea urchin eggs and embryos were investigated by gel filtration. Four different forms were found in Hemicentrotus pulcherrimus, and three forms in Anthocidaris crassispina and Pseudocentrotus depressus.The first and second forms (designated AcP-1 and AcP-2) had the highest activity in the range of pH 5.6-6.0. The third (designated AcP-3) had an apparent optimum pH between pH 4.3 and 4.8, and the fourth (designated AcP-4) showed the maximum activity at pH 3.0. AcP-1 was much more thermolabile than AcP-2 and AcP-3 at 56°C. NaF inhibited AcP-2, AcP-3, and AcP-4 but not AcP-1. AcP-1, AcP-2, and AcP-3 were observed in the three species, whereas AcP-4 was not detected in A. crassispina and P. depressus. AcP-1, AcP-2, and AcP-3 were separted by gel filtration.AcP-1 and AcP-2 of A. crassispina and H. pulcherrimus were studied in developing embryos. The behavior of these forms in gel filtration changed during development, from unfertilized eggs to the pluteus stage.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 187-192 
    ISSN: 0148-7280
    Keywords: zona isolation ; collagenase ; receptor for sperm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Zonae pellucidae were collected from bovine ovaries by chopping, dispersing the chopped tissue with collagenase, sieving through nylon mesh screens, and pipetting. The zonae were free of corona cell processes when examined under the scanning electron microscope. Solutions of zonae obtained with collagenase exhibited the same antigenic and sperm receptor properties as those obtained without enzyme treatment.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 207-211 
    ISSN: 0148-7280
    Keywords: sperm ; capacitation ; acrosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Suspensions of nearly 100% viable golden hamster sperm were prepared by passing washed cauda epididymal sperm through a column of 0.25-0.3 mm glass beads. Incubations of these viable sperm under in vitro capacitation conditions in volumes of 0.1 or 1 ml (2-2.5 × 106/ml) resulted in 85-92% viable sperm after four hours and 45 minutes of incubation. More than 70% of these sperm were judged to have been capacitated after four hours and 45 minutes of incubation on the basis of their having undergone acrosome reactions and the presence of high numbers of sperm exhibiting the activated motility characteristic of capacitated hamster sperm.Thus, for the first time, procedures are available that will yield large numbers of viable capacitated sperm for biochemical analysis and that will also allow other studies of hamster sperm capacitation with minimum interference from molecules released from dead sperm.
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  • 5
    ISSN: 0148-7280
    Keywords: speramtozoon-copepoda (My tilicola intestinalis) ; external morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The external structure of the male gamete of Mytilicola intestinalis is studied under a scanning electron microscope and compared with transmission electron micrographs of thin sections corresponding to the different parts of same. The cell in question is long and filiform, showing, along a significant part of its length, two ridges or expansions helicoidally arranged and diametrically opposed. Four different parts or segments can be identified in this spermatozoon: segment A, characterized by its screw-like aspect; segment B, the longest, provided with well-developed helicoidal expansions; segment C, showing an uneven surface and lacking expansions; and segment D, with a smooth surface and decreasing diameter. The significance of this original structure in a spermatozoon, considered immobile until now, is discussed, stating different hypotheses with regard to the possible mobility of the cell just before fertilization takes place.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 283-293 
    ISSN: 0148-7280
    Keywords: in vitro fertilization ; mouse ; second polar body formation ; second meiotic division ; spindle ; polarizing microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The second meiotic division and polar body formation in mouse eggs fertilized in vitro were observed by phase-contrast and polarizing microscopy, and recorded by time-lapse cinematography. Eggs were collected from oviducts of mice that had been superovulated by injections of PMS and HCG. Some eggs, inseminated with spermatozoa that had been collected from caudae epididymides of mature male mice and cultured for two to three hours before insemination, were observed continuously on a glass slide under a phase microscope. Other eggs were inseminated in Petri dishes in a 5% CO2 incubator and examined every 20 minutes for 180 minutes. Compatible results in both sets of eggs showed that formation of the second polar body began 25-40 minutes after fusion of spermatozoon with the vitellus; it was completed 40-60 minutes later; anaphase II lasted approximately five minutes before the appearance of the furrow abstricting the second polar body. It is suggested that the furrowing associated with second polar body formation is guided by the same kind of forces that divide a cell mitotically.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 193-199 
    ISSN: 0148-7280
    Keywords: double spermatozoa ; human prolactin-secreting adenoma ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In a man with a pituitary prolactin-secreting adenoma almost only double spermatozoa were produced. These cells were almost completely enveloped in a unique membrane, a common bilocular acrosome capped two paired nuclei, and all the other organelles were double. After 120 days of treatment with 2-brom-α-ergocryptine the prolactin level was corrected, and only normal, single spermatozoa were produced. The authors suggest that a high prolactin level inhibits cell division.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 201-206 
    ISSN: 0148-7280
    Keywords: zona pellucida ; antibody ; ovary ; calf ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Treatment of bovine ovary sections with rabbit antibovine zona serum followed by fluorescein-conjugated goat antirabbit IgG produced a specific fluorescent staining only of the zonae pellucidae. Fluorescence was greater near the inner and outer surface of the zona, suggesting that either the same antigen occurs in higher concentration in these regions or that there is more than one antigen, the most immunogenic being located peripherally. In some atretic follicles fluorescent material appeared to diffuse into the degenerating oocyte and into the intercellular spaces of the cumulus oophorus.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 213-222 
    ISSN: 0148-7280
    Keywords: urethan effect ; cleavage induction ; parthenogenesis ; sea urchin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effect of urethan on artificial induction of cleavage in eggs of the sea urchin, Hemicentrotus pulcherrimus, was studied. When the eggs were exposed for 20 minutes to seawater containing urethan (final concentration, 0.08 M) after butyric acid-activation and then treated with hypertonic seawater, the cleavage rate was enchanced by about 1.5 times as compared with the nontreated eggs. In the eggs exposed to urethan-seawater for over 70 minutes many clear spots appeared throughout the cytoplasm. Simultaneously, the pigment granules, which had been embedded within the cortex, migrated to the inner cytoplasm and encircled a monastral centrosphere and clear spots. The clear spots were composed of microtubules much like cytasters, and in the central region of them centrioles were not yet found. The eggs in which the pigment granules disappeared from the cortex may be more susceptible to cleavage induction by succeeding hypertonic treatment.
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 920-922 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Bromomethyl-2,2-dichlorocyclopropane as an Alkylation ReagentReaction of 1-bromomethyl-2,2-dichlorocyclopropane (1) with nucleophiles yields substitution products 2-7 without rearrangement of the dichlorocyclopropane system.
    Notes: Reaktion von 1-Brommethyl-2,2-dichlorcyclopropan (1) mit Nukleophilen ergibt die Substitutionsprodukte 2-7 unter Erhaltung des Dichlorcyclopropansystems.
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  • 12
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Farbstoffe aus Elsinoe, VII1). - Korrektur der Struktur eines Zwischenprodukts; Darstellung eines Dinaphtho[2,1-b:1′,2′-d]furan-5,9-dionsDie durch Polyphosphorsäure-Cyclisierung des 2-(o-Iodphenylacetyl)malonsäureesters 3 erhaltenen Produkte wurden erneut untersucht und ihre Strukturen korrigiert. Vermutlich ergibt Iodabspaltung zunächst 7, und nachfolgende Oxidation 8 (statt 5). Verbindung 8 wird zu 11 (statt 2) dehydratisiert. 11 steht mit 10 (statt 6) im Gleichgewicht.
    Notes: The products of the polyphosphoric acid cyclization of the 2-(o-iodophenylacetyl)malonate 3 have been reinvestigated and their structures revised. The reaction proceeds with loss of iodine, presumably forming 7, which is oxidized to 8 (instead of 5) followed by dehydration to 11 (instead of 2) and equilibration to hydroquinone 10 (instead of 6).
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 950-958 
    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 Substituted 3-0xo-1,2,6-thiadiazine 1,l-Dioxides3-Oxo-1,2,6-thiadiazine 1,1-dioxides 4 are synthesized from monosubstituted sulfamides 2 and methyl methoxymethylenemalonates (1). 2,5-Disubstituted 3-oxo-1,2,6-thiadiazine 1,1-dioxides 10 are prepared by reaction of alkylsulfamoyl chlorides 7 with aminoalkylidenemalonates 6. Halogenation, methylation and substitution reactions of 10 are described.
    Notes: Methoxymethylenmalonsäure-methylester (1) und monosubstituierte Sulfamide 2 setzen sich zu 3-Oxo-1,2,6-thiadiazin-1,1-dioxiden 4 um. 2,5-Disubstituierte 3-Oxo-1,2,6-thiadiazin-1,1-dioxide 10 werden aus Aminoalkylidenmalonsäureestern 6 und Alkylsulfaminsäurechloriden 7 erhalten. Es werden Halogenierung, Methylierung sowie Substitutionsreaktionen von 10 beschrieben.
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  • 14
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Amino Acids and Peptides, II. - Preparation of 2-Aminooxazole Derivatives from Peptide Amides with Hexafluoroacetic AnhydrideC-Terminal amino acid amide residues of peptide amides react with hexafluoroacetic anhydride to form stable 5-(trifluoroacetylamino)oxazole derivatives. Several representatives of this class of compounds have been synthesized and their structures determined by 1H-NMR and mass spectrometry and by their chemical reactions. The heterocyclization reaction can be used for the formation of volatile derivatives in the analysis of peptide amides on a microgram scale and for the identification of the C-terminal amino acid residue in peptide amides.
    Notes: C-Terminale Aminosäureamidreste von Peptidamiden reagieren mit Hexafluoracetanhydrid in guten Ausbeuten zu stabilen 5-(Trifluoracetylamino)oxazolderivaten. Verschiedene Vertreter dieser Verbindungen wurden dargestellt und ihre Struktur durch 1H-NMR-, Massenspektrometrie und chemische Reaktionen charakterisiert. Die Heterocyclisierungsreaktion kann im Mikrogramm-Maßstab zur Herstellung flüchtiger Derivate bei der Analytik von Peptidamiden und zur Identifizierung der C-terminalen Aminosäure von Peptidamiden benutzt werden.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1028-1035 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Anhydrides in the A-Seco-steroid Series with 10β-Methyl or 10β-Methoxycarbonyl SubstitutionA-Seco- and A-nor-A-seco-dicarboxylic acids with cholestane skeleton and their anhydrides have been prepared in good yields from 2α-bromo-3-ketones by Baeyer-Villiger oxidation, dehydro-bromination of the resulting lactones, and oxidative cleavage of their double bond. 19-Functionalized A-nor-A-seco-steroid dicarboxylic acids have thus been obtained for the first time.
    Notes: A-Seco- und A-Nor-A-seco-dicarbonsäuren der Cholestanreihe und deren Anhydride wurden aus 2α-Brom-3-ketonen durch Baeyer-Villiger-Oxidation, Dehydrobromierung der erhaltenen Lactone und oxidative Spaltung derer Doppelbindung in guter Ausbeute dargestellt. 19-Funktionalisierte A-Nor-A-seco-steroiddicarbonsäuren wurden so erstmals zugänglich.
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1036-1047 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Circular Dichroism, LXXIII1). - Chiroptical Properties of Cyclic AnhydridesCyclic anhydrides exhibit two to four Cotton effects below 260 nm. Applying qualitative MO theory leads to predictions about the correlation between absolute conformation and signs of the first two CD bands for such anhydrides with an inherently achiral or inherently chiral (C2 symmetry) chromophore. For the first, the two CD bands at longest wavelengths have the same sign and conform with the sector rule of figure 5 with 12 sectors. For the anhydride chromophore with C2 symmetry a helicity rule holds: A negative interplanar angle between the two planes of the C = O groups leads to a negative Cotton effect around 240 nm and to a positive one around 220 nm.
    Notes: Cyclische Anhydride zeigen zwei bis vier Cotton-Effekte unterhalb von 260 nm. Mit Hilfe der qualitativen MO-Theorie lassen sich Voraussagen über den Zusammenhang zwischen absoluter Konformation und Vorzeichen der ersten beiden CD-Banden für solche Anhydride mit inhärent achiralem und inhärent chiralem (C2-Symmetrie) Chromophor ableiten. Bei ersteren haben die beiden längstwelligen CD-Banden gleiches Vorzeichen, dafür gilt die Sektorregel mit 12 Sektoren der Abbildung 5. Für den Anhydridchromophor mit C2-Symmetrie gilt eine Helizitätsregel: Ein negativer Interplanarwinkel zwischen den beiden Ebenen der C = O-Gruppen führt zu einem negativen Cotton-Effekt um 240 nm und zu einem positiven um 220 nm.
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1232-1257 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on the Occurence of Hydrogen Transfer, 58. - Possibilities and Limits of Photochemically Induced Asymmetric Synthesis
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  • 18
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vincetene, a Benzopyrroloisoquinoline Alkaloid, from Cynanchum Vincetoxicum (L.) Pers. (Asclepiadaceae)Cynanchum vincetoxicum contains traces of an alkaloid C22H27NO3, whose structure has been shown to be 6-(3-hydroxy-cis-1-butenyl)-2,3-dimethoxy-7,9,10,11,11a,12-hexahydrobenzo[f]-pyrrolo[1,2-6]isoquinoline (2) and has been confirmed by synthesis of the rac-dihydrodesoxy-derivative 18.
    Notes: Cynanchum vincetoxicum (L.) Pers. enthält Spuren eines Alkaloids C22H27NO3, dessen Struktur als 6-(3-Hydroxy-cis-1-butenyl)-2,3-dimethoxy-7,9,10,11,11a, 12-hexahydrobenzo[f]pyrrolo[1,2-b]-isochinolin (2) geklärt und durch Synthese des rac-Dihydrodesoxy-Derivates 18 gesichert wurde.
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979) 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1300-1308 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereoselective Synthesis of Cyclopentanone DerivativesVarious trans-disubstituted cyclopentanone derivatives are obtained via stereoselective Michael addition to 4-oxo-2-cyclopenten-1-yl acetate (1). The limitations of the method are shown.
    Notes: Verschiedene trans-disubsituierte Cyclopentanonderivate werden durch stereoselektive Michael-Addition an Essigsäure-(4-oxo-2-cyclopenten-1-ylester) (1) erhalten. Die Grenzen der Methodik werden aufgezeigt.
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  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 387-391 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocycles by Annelation to 4-Pyridinols, II.  -  Thieno[3,2-c]pyridin-3-olsHerrn Prof. Dr. Werner Schultheis zum 75. Geburtstag gewidmet.Thieno[3,2-c]pyridin-3-ols 4 are accessible from 4-hydroxy-3-pyridine carboxylates 1 via their 4-chloro derivatives 2 on replacement of the chlorine by mercaptoacetic esters and simultaneous ring-closure. Thioacetamide transforms the 4-chloropyridines 2 into 4-pyridinethiols 3, which likewise yield thieno[3,2-c]pyridin-3-ols 4 on reaction with chloroacetonitrile. The alkali salts of 4 are transformed into enol esters 5 by reaction with acid chlorides.
    Notes: Thieno[3,2-c]pyridin-3-ole 4 werden aus 4-Hydroxy-3-pyridincarbonsäureestern 1 über deren 4-Chlorderivate 2 und Austausch des Chlors mit Mercaptoessigsäureester bei gleichzeitigem Ringschluß erhalten. Thioacetamid überführt die 4-Chlorpyridine 2 in 4-Pyridinthiole 3, die mit Chloracetonitril ebenfalls Thieno[3,2-c]pyridin-3-ole 4 liefern. Die Alkalisalze von 4 werden mit Säurechloriden in Enolester 5 übergeführt.
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  • 22
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocycles by Annelation to 4-Pyridinols, I.  -  Furo[3,2-c]pyridin-3-ols and Furo[3,2-c]pyridin-3(2H)-onesHerrn Prof. Werner Schultheis zum 75. Geburtstag gewidmet.The synthesis of furo[3,2-c]pyridin-3-ols 3 from 4-hydroxypyridinecarboxylates 2 is described. Hydrolysis of the ester group at C-2 of compound 3e yields furo[3,2-c]pyridin-3(2H)-one 4b (R4 = H) with loss of carbon dioxide. Condensation of 4b with aldehyds affords the unsaturated ketones 5, which on hydrogenolysis from furo[3,2-c]pyridin-3(2H)-ones 4 with an alkyl substituent at C-2. Alternatively compounds 4 are accessible on ring closure of 3-acyl-4-hydroxypyridines by bromination/dehydrobromination. The furo[3,2-c]pyridin-3-ols 3 and furo[3,2-c]pyridin-3(2H)-ones 4 are transformed into enol esters 15.
    Notes: Es wird die Synthese von Furo[3,2-c]pyridin-3-olen 3 aus 4-Hydroxy-3-pyridincarbonsäureestern 2 beschrieben. Hydrolyse der Estergruppe an C-2 von 3e führt unter Decarboxylierung zum Furo[3,2-c]pyridin-3(2H)-on 4b (R4 = H), aus dem mit Aldehyden die ungesättigten Ketone 5 erhalten werden, deren Hydrierung Furo[3,2-c]pyridin-3(2H)-one 4 mit Alkylresten an C-2 ergibt. Ein alternativer Zugang zu den Verbindungen 4 besteht im Ringschluß von 3-Acyl-4-hydroxy-pyridinen 14 durch Bromierung/Dehydrobromierung. Die Furo[3,2-c]pyridin-3-ole 3 und Furo[3,2-c]pyridin-3(2H)-one 4 werden in die Enolester 15 übergeführt.
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  • 23
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Occurrence of Hydrogen Transfer, 57.  -  Some Examples of the Diastereoselective Hydrogenation of Compounds Containing Prochiral C=C Bonds2,3)(1R,2S)-N,N-Dimethylephedrinium chloride, (1S,2S)-N,N-dimethylpseudoephedrinium chloride, (1R,2S)-N-methylephedrine, (1S,2S)-N-methylpseudoephedrine and [(2S)-2-hydroxy-2-phenylethyl]trimethylammonium chloride were esterified with α- and β-methylcinnam=c acid to give 1-4 and 7, which were then hydrogenated over Raney-nickel, palladium, platinum and a series of noble metal supported catalysts. The reduced esters were hydrolysed and the optical yields of the α- or β-methyldihydrocinnamic acids measured. These varied between 4 and 68%, depending upon the structure of the optically active component used. In those cases where the optical yields were greater than 10% the absolute configuration of the α- or P-methyldihydrocinnamic acids were determined via the configuration at C-1 of the ephedrine ester. Knowledge of the absolute configuration of the α- or β-methyldihydrocinnamic acids, in conjunction with the known absolute configuration of the ephedrine component, allowed conclusions to be drawn concerning the conformation of the chemisorbed molecule at the catalyst surface. The amides 5 and 6, prepared by reaction of ephedrine or pseudoephedrine with α- or β-methylcinnamic acid, exhibit optical inductions in the range 3 -24% after hydrogenation with Raney-nickel. After hydrogention and hydrolysis, the ester obtained from N-methylephedrine and α-benzamidocinnamic acid gave (+ )-(R)-phenylalanine in an optical yield of 26%. Electroreduction of 1 α and 2 β at a mercury cathode and subsequent hydrolysis yields α- and β-methyldihydrocinnamic acid, respectively, in optical yields of 0.3 and 7%. The electroreduction of β-menth-3-yl trans-α- or trans-β-methylcinnamate yields the corresponding α- or β-methyldihydrocinnamic acids in optical yields
    Notes: (1R,2S)-N,N-Dimethylephedriniumchlorid, (1S,2S)-N,N-Dimethylpseudoephedriniumchlorid, (1R,2S)-N-Methylephedrin, (1S,2S)-N-Methylpseudoephedrin und [(2S)-2-Hydroxy-2-phenyl-ethyl]trimethylammoniumchlorid werden mit α- und β-Methylzimtsäure zu 1-4 und 7 verestert und an Raney-Nickel, Palladium, Platin und einer Reihe von Edelmetallträgerkatalysatoren hydriert. Die hydrierten Ester werden verseift und die optische Ausbeute der α- bzw. β-Methyldihydrozimtsäure bestimmt. Die optischen Ausbeuten bewegen sich in Abhängigkeit von der optisch aktiven Hilfskomponente zwischen 68 und 4%. Bei optischen Ausbeuten über 10% wird die absolute Konfiguration der α- oder β-Methyldihydrozimtsäure von der Konfiguration am C-1 des Ephedrinderivates bestimmt. Die Kenntnis der absoluten Konfiguration der α- bzw. β-Methyldihydrozimtsäure erlaubt, wenn die absolute Konfiguration der Hilfskomponente bekannt ist, auf Grund eines plausiblen Modells Rückschlüsse auf die Konformation der chemisorbierten Molekel am Kontakt. Bei den aus Ephedrin und Pseudoephedrin mit α- und β-Methylzimtsäure dargestellten Säureamiden 5 und 6 liegt die optische Induktion der α- bzw. β-Methyldihydrozimtsäure nach Hydrierung mit Raney-Nickel bei 3-24%. Aus dem Ester 8 des N-Methylephedrins und der α-Benzamidozimtsäure erhält man nach Hydrierung und Hydrolyse (+)-(R)-Phenylalanin in einer optischen Ausbeute von 26%.  -  Bei der Elektroreduktion von 1α und 1β an einer Quecksilberkathode liegt die optische Ausbeute der nach Verseifung gewonnenen α- bzw. β-Methyldihydrozimtsäure bei 0.3 bzw. 7%. Die Elektroreduktion des trans-α- oder trans-β-Methylzimtsäure-(p-menth-3-ylesters) liefert die entsprechenden α- bzw. β-Methyldihydrozimtsäuren mit optischen Ausbeuten zwischen 0 und 2%.
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  • 24
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 400-407 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Seven-Membered Rings by 1,5-Cycloadditions, V.  -  Perhydro-1,4-diazepines1,3-Dialkyl-1,3-imidazolidines 2 react with cyclic enol ethers 1 in presence of trifluoroacetic acid to give bicyclic perhydro-1,4-diazepines 3 which are transformed by lithium tetrahydridoaluminate to perhydro-1,4-diazepinylalkanols 8. In contrast, acyclic enol ethers 9 do not undergo polar 1,5-cycloaddition with imidazolidines 2 but give (dialkoxyalkyl)ethylenediamines 10 in low yields.
    Notes: 1,3-Dialkyl-1,3-imidiazolidine 2 reagieren mit den cyclischen Enolethern 1 in Gegenwart von Trifluoressigsäure zu den bicyclischen Perhydro-1,4-diazepinen 3, die mit Lithium-tetrahydridoaluminat die Perhydro-1,4-diazepinylalkanole 8 geben. Die acyclischen Enolether 9 gehen dagegen keine polare 1,5-Cycloaddition ein und führen mit den Imidazolidinen 2 in niedriger Ausbeute zu den (Dialkoxyalkyl)ethylendiaminen 10.
    Additional Material: 1 Tab.
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  • 25
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 438-441 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Note on the Assignment of Isomeric Ethers Derived from TropoloneThe Eu(dpm)3-shifted 1H-NMR spectra of the two isomeric ethers obtained from 4-tert-butyl-tropolone with diazomethane do not allow unambiguous assignment of the isomers. However, this is possible on the basis of the 13C-1H coupling pattern of the C=O signals in the 13C-spectra.
    Notes: Die beiden aus 4-tert-Butyltropolon mit Diazomethan erhaltenen isomeren Ether werden an Hand der 13C-1H-Kopplung der C=O-Signale in den 13C-NMR-Spektren zugeordnet. Dieses war mit den durch Eu(dpm)3 verschobenen 1H-Spektren nicht eindeutig möglich.
    Additional Material: 2 Tab.
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  • 26
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979) 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 27
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 443-445 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 5-Hydroxy-1,7-naphthyridineN-(p-Toluenesulfonyl)glycine ester 1b reacts with 2-(bromomethyl)nicotinic ester 2 to form the nicotinic acid derivative 3b. Cyclization of 3b, by elimination of sulfinic acid, leads to the 1,7-naphthyridine derivative 7, from which the title compound 8 is formed.
    Notes: N-(p-Toluolsulfonyl)glycinester 1b reagiert mit 2-(Brommethyl)nicotinsäureester 2 zum Nicotinsäurederivat 3b. Dieses läßt sich unter Eliminierung von Sulfinsäure zum 1,7-Naphthyridin-derivat 7 cyclisieren, aus dem die im Titel genannte Verbindung 8 erhalten wird.
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  • 28
    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, XLI. - 5,6-Dihydro-4H-1,3-thiazines from α-Metalated Isocyanides and EpisulfidesSeveral 5,6-dihydro-4H-1,3-thiazines 7 were prepared (via 3-mercaptoalkyl isocyanides 6) from α-lithiated isocyanides 1 and episulfides 5.
    Notes: Aus lithiierten Isocyaniden 1 und Episulfiden 5 wurden (über 3-Mercaptoalkylisocyanide 6) einige 5,6-Dihydro-4H-1,3-thiazine 7 darstellt.
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  • 29
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 457-460 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (Fluorosilyl)hydrazones and Cyclization to 1,2-Diaza-3-sila-5-cyclopentenes(Fluorosilyl)hydrazones 2 - 5 are formed in the reaction of lithiated hydrazones 1 with fluorosilanes. On reaction with butyllithium 2 - 5 cyclize to give the five-membered heterocycles 8 - 11. Substituted compounds 6, 7 are obtained in a competing reaction. - The mass, 1H, 19F, and29Si-NMR spectra of the compounds prepared are reported.
    Notes: (Fluorsilyl)hydrazone 2-5 entstehen aus lithiierten Hydrazonen 1 mit Fluorsilanen. Die Reaktion von 2-5 mit Butyllithium führt unter Cyclisierung zur Bildung der fünfgliedrigen Heterocyclen 8-11. In einer Konkurrenzreaktion werden substituierte Verbindungen 6, 7, gebildet. - Die Massenspektren, 1 H-, 19F- und 29Si-NMR-Spektren der dargestellten Verbindungen werden mitgeteilt.
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  • 30
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangements of Vinylogous Acyl Chlorides, XXIII. - Investigations on the Thermal Reactivity of (Z)-Perchloro-2,4-pentadienoyl Chloride and (Z)-Perchloro-2,4-pentadienoic Acid by 14C-LabellingDuring the preparation of the chloride [14C]-1b from the acid [1-14C]-3b with phosphorus pentachloride by heating the mixture for 48 hours at 110°C, a complete equipartition of the activity on C-1 and C-5 of 1b is observed. Equipartition also occurs when the acid [1-14C]-3b is transformed into the pyrone 4b on C-2 and C-6 of this compound. The conclusions drawn from this with respect to the mechanism of the thermal reactions of 1b and 3b are presented.
    Notes: Die Darstellung des Säurechlorids [14C]-1b durch 48stündiges Erhitzen der Säure [1-14C]-3b mit Phosphor(V)-chlorid auf 110°C ist mit einer vollständigen Gleichverteilung der Aktivität auf das C-1 und C-5 von 1b verbunden. Eine Gleichverteilung wird auch bei der Überführung der Säure [1-14-C]-3b in das Pyron 4b auf dessen C-2 und C-6 festgestellt. Hieraus wurden Schlußfolgerungen auf den Mechanismus der thermischen Reaktionen von 1 b und 3b gezogenen.
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  • 31
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1554-1559 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sila-Drugs, 11.  -  Diphenyl(3-piperidinopropyl)silanol, a Sila-Analogue of DifenidolDiphenyl(3-piperidinopropyl)silanol (6b), a sila-analogue of the drug difenidol (6a), and its methoiodide 7 were synthesized for the first time according to scheme 1.  -  The pharmacological and toxicological properties of the analogues 6a and 6b were investigated comparatively.
    Notes: Diphenyl(3-piperidinopropyl)silanol (6b), ein Sila-Analogon des Arzneimittels Difenidol (6a), und dessen Methoiodid 7 wurden erstmals gemäß Schema 1 synthetisiert.  -  Die pharmakologischen und toxikologischen Eigenschaften der Analoga 6a und 6b wurden vergleichend untersucht.
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  • 32
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes between Neutral Molecules, V.  -  Urea, Thiourea and Malodinitrile Complexes of Noncyclic Crown Type Polyethers with Pyridine N-Oxide SubunitsAcyclic crown type polyethers with one and two pyridine or pyridine-N-oxide nuclei as rigid donor units, have been synthesized. Their complexing behaviour is compared: The pyridine N-oxide ligands reveal reduced complexing ability towards alkali metal cations. The neutral molecules urea, thiourea and malodinitrile easily form stoichiometric complexes with both ligand systems.
    Notes: Acyclische Kronenetheranaloga mit ein und zwei Pyridin- oder Pyridin-N-oxid-Einheiten als starren Donorgruppen wurden synthetisiert. Ihr Komplexierungsverhalten gegenüber Alkalimetallkationen wird verglichen: Die N-Oxide bilden weniger leicht kristalline Komplexe. Mit den Neutralmolekülen Harnstoff, Thioharnstoff und Malonsäuredinitril wurden stöchiometrische Komplexe erhalten.
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  • 33
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 484-491 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of (-)-(S)- and (+)-(R)-Goniothalamin; Absolute Configuration of the Naturally Occurring (+)-Goniothalamin(-)-(S)-Goniothalamin and its naturally occurring (+)-(R)-enantiometer were synthesised from configurationally defined precursors. The absolute configurations were additionally confirmed by ozonolysis to (-)-(S)- and (+)-(R)-malic acid. The absolute configuration given for the compound in the literature is thus corrected.
    Notes: (-)-(S)-Goniothalamin und das (+)-(R)-Enantiomer wurden aus konfigurativ definierten Vorstufen synthetisiert. Die absoluten Konfigurationen wurden zusätzlich durch Ozonabbau zu (-)-(S)- und (+)-(R)-Äpfelsäure bestätigt. Die in der Literatur angegebene absolute Konfiguration des Naturstoffs wird berichtigt.
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  • 34
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 503-521 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Amination of 1′,4′-Dihydroxy-2′-acetonaphthoneUnder conditions of oxidative amination 1′,4′-dihydroxy-2′-acetonaphthone (1) and arylamines 3 react to yield arylaminonaphthoquinones 4 (C-N-bond formation), aminoarylquinones 8, phenanthridinequinones 9 (C—C-bond formation) and quinones 10 (C—C- and C—N-bond formation). Intermediates of the multistep reaction are isolated and characterised. The results are compared with those of the reaction of 2-acetyl-1,4-naphthoquinone (2) with the arylamines 3.
    Notes: 1′,4′-Dihydroxy-2′-acetonaphthon (1) reagiert unter den Bedingungen der oxidativen Aminierung mit Arylaminen 3 zu Arylaminonaphthochinonen 4 (C- N-Verknüpfung), Aminoarylchinonen 8, Phenanthridinchinonen 9 (C-C-Verknüpfung) und den Chinonen 10 (C-N- und C-C-Verknüpfung). Zwischenprodukte der mehrstufigen Reaktion wurden isoliert und charakterisiert. Die Ergebnisse werden mit denjenigen der Reaktion von 2-Acetyl-1,4-naphthochinon (2) mit Arylaminen 3 verglichen.
    Additional Material: 1 Ill.
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  • 35
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 492-502 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Organophosphorus Compounds, XLIV. - Synthesis of Dialkyl 3-Oxo-1-alkenylphosphonatesThe Michaelis-Arbusov reaction of 2-chlorovinyl ketones 1 with trialkyl phosphites 2 gives 2-acylvinylphosphonates 3 as well as enolphosphates 4 and 3-oxo-1,1-alkanediyldiphosphonates 5. Using the Michaelis-Becker procedure only the compounds 4 and 5 are formed as demonstrated in the case of 4d and 5d. Reaction of trimethyl and triethyl phosphite (2a and 2b) with 2-chlorovinyl ketones 1a - 1d yields mixtures of products 3a-3e, 4a-4e and 5a-5e; whereas reaction with triisopropyl phosphite (2c) gives predominantly compound 3. For example, 2c and 1a react to form a mixture consisting mainly of 2-acylvinylphosphonate 3f and a small amount of 3-oxo-1,1-alkanediyldiphosphonate 5f. Only the 2-acylvinylphosphonate 3g is isolated on reaction of 2c with 1d.
    Notes: Die Umsetzung von 2-Chlorvinylketonen 1 mit Trialkylphosphiten 2 nach Michaelis-Arbusow führt nicht nur zu den erwarteten 2-Acylvinylphosphonaten 3, sondern auch zu den Enolphosphaten 4 und zu den 3-Oxo-1,1-alkandiyldiphosphonaten 5. Bei Anwendung der Michaelis-Becker-Variante entstehen jedoch ausschließlich die Verbindungstypen 4 und 5, wie anhand der Reaktionsprodukte 4d und 5d gezeigt werden konnte. Während Trimethyl- und Triethylphosphit (2a bzw. 2b) mit den 2-Chlorvinylketonen 1 a - 1d jeweils die Produktgemische 3a-3e, 4a-4e und 5a-5e liefern, entstehen bei Verwendung von Triisopropylphosphit (2c) bisweilen nur Reaktionsprodukte des im Titel genannten Typs 3. So liefert 2c mit 1a nur ein Gemisch aus der Hauptmenge des 2-Acylvinylphosphonats 3f und des in untergeordneter Menge auftretenden 3-Oxo-1,1-alkandiyidiphosphonats 5f. Nach Umsetzung von 2c mit 1d wird als definiertes Reaktionsprodukt nur noch das 2-Acylvinylphosphonat 3g isoliert.
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  • 36
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 522-527 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acetalization Reactions with N,N-Dimethylformamide-Dialkyl Sulfate AdductsHern Professor Dr. Hellmut Bredereck zum 75. Geburtstag gewidmet.The adducts 2 and 3 from N,N-dimethylformamide and dialkyl sulfate adducts react in the presence of alcohols with aromatic aldehydes, α, β-unsaturated aldehydes, and ketones to form acetals and ketals, respectively. The influence of the nature of the carbonyl compound on acetalization is considered.
    Notes: Die Addukte 2 und 3 aus N,N-Dimethylformamid und Dialkylsulfaten setzen sich in Gegenwart von Alkoholen mit aromatischen Aldehyden, α, β-ungesättigten Aldehyden oder Ketonen zu Acetalen bzw. Ketalen um. Der Einfluß der Art der Carbonylverbindung auf den Verlauf der Acetalisierung wird untersucht.
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  • 37
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mechanism of Formation of Azavinylogous Formamidinium Salts from Formamides and 2,4,6-Trichloro-1,3,5-triazine; a Simple Synthesis of N2-(Dimethylaminomethylene)-N1,N1-dimethylformamidinium ChlorideHerrn Professor Dr. Hellmut Bredereck zum 75. Geburtstag gewidmet.A new mechanism is proposed for the formation of azavinylogous formamidinium salts 1 from N,N-dialkylformamides and 2,4,6-trichloro-1,3,5-triazine. Furthermore, a new simple synthesis of 1a from the iminium chloride 12, potassium cyanate, and N,N-dimethylformamide is described. Preparation of the formamidinium compound 1a does not require isolation of the salt 12.
    Notes: Für die Bildung azavinyloger Formamidiniumsalze 1 aus N,N-Dialkylformamiden und 2,4,6-Trichlor-1,3,5-trizin wird eine neuer Mechanismus vorgeschlagen. Außerdem wird eine neue, einfache Synthese für 1a aus Iminiumchlorid 12, Kaliumcyanat und N,N-Dimethylformamid beschrieben. Diese gelingt auch ohne vorherige Isolierung von 12 (Eintopfverfahren).
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  • 38
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 547-553 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Sulfonyl Ethers, 17.-Acylation of the Anions of Arylsulfonylmethyl Methyl Ethersα-Arylsulfonyl-α-methoxyacetic acids 2 and their esters 4a -c, α-arylsulfonyl-α-methoxy ketones 4d-o, and α-methoxy-β-disulfones 6 are obtained by acylation of α-metalated α-sulfonyl ethers 1. Reaction conditions and properties are described.
    Notes: Aus α-metallierten α-Sulfonylethern 1 werden durch gezielte Acylierung α-Arylsulfonyl-α-methoxyessigsäuren 2 sowie deren Ester 4a-c, α-Arylsulfonyl-α-methoxyketone 4d-o und α-Methoxy-β-disulfone 6 erhalten. Reaktionsbedingungen und Eigenschaften werden beschrieben.
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  • 39
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1657-1664 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vitamin B6; a New Synthesis by Diels-Alder Reaction**)4-Methyloxazole (1a) and 3-methylsulfonyl-2,5-dihydrofuran (7) undergo Diels-Alder reaction to give the pyridoxine derivative 8 with elimination of methanesulfinic acid. Treatment of 8 with hydrogen chloride furnishes the dichloride 10, from which pyridoxine (12) is obtained by direct hydrolysis or by way of the intermediary triacetate 14. This reaction sequence provides an efficient synthesis of vitamin B6.
    Notes: 4-Methyloxazol (1a) geht mit 3-Methylsulfonyl-2,5-dihydrofuran (7) eine Diels-Alder-Reaktion ein, bei der unter Eliminierung von Methansulfinsäure das Pyridoxinderivat 8 entsteht. Dessen Behandlung mit Chlorwasserstoff führt zum Dichlorid 10, aus dem durch direkte Hydrolyse oder über das Triacetat 14 Pyridoxin (12) erhalten wird. Die Reaktionsfolge stellt eine ergiebige Synthese für Vitamin B6 dar.
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  • 40
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Scavenger Reactions of Short-lived Radicals, XIX1). - Reactions of 2,2′-Disubstituted 2,2′-Azopropanes with Trialkylstannyl and Trialkylsilyl Radicals2,2′-Disubstituted 2,2′-azopropanes 1a-c (X=Cl, PhS. PhO) undergo a rapid radical chain reaction with Me3SnH or Me6Sn2 to yield acetone azine (3) and Me3SnX (also phenol in the case of X=PhO). 1d (X=MeCOO) reacts analogously only with Me3SnH whereas, with Me6Sn2, the initiator tert-butoxyl radicals give only equimolar amounts of the azine 3. The corresponding X is split off as a radical X. or, as a consequence of fragmentation, as Me3SnX. The mechanisms involved are discussed. Et3SiH reacts only with 1a and b (X=Cl, PhS) in which X can undergo a SH2 reaction with silyl radicals to yield acetone azine (3).
    Notes: 2,2′-Disubstituierte 2,2′-Azopropane 1a-c (X=Cl, PhS, PhO) geben mit Me3SnH und Me6Sn2 eine schnelle radikalische Kettenreaktion zu Acetonazin (3) und Me3SnX (für X=PhO auch Phenol). 1d (X=MeCOO) reagiert analog nur mit Me3SnH, mit Me6Sn2 liefern die als Initiatoren eingesetzten tert-Butoxylradikale nur äquimolare Mengen an Acetonazin (3). Jeweils wird X als Radikal X. abgespalten oder unter Fragmentierung als Me3SnX. Die Mechanismen werden erörtert. Et3SiH reagiert nur mit 1a und b (X=Cl, PhS), bei denen eine SH2-Reaktion von Silylradikalen an X möglich ist, zu Acetonazin (3).
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  • 41
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    Liebigs Annalen 1979 (1979), S. 1682-1688 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Hydrolysis of Amadori Rearrangement Products from 2-Amino-2-deoxy-D-hexoses and D-Hexuronic AcidsCondensation of 2-amino-2-deoxyhexoses (D-gluco or D-galacto configuration) with hexuronic acids (D-gluco or D-galacto configuration) in methanol gave the Amadori rearrangement products 6-(2-deoxy-α-D-glucopyranos-2-ylamino)-6-deoxy-β-D- lyxo-5-hexulofuranosonic acid (1) and -α-D-arabino-5-hexulofuranosonic acid (2) as well as 6-(2-deoxy-D-galactopyranos-2-ylamino)-6-deoxy-β-D lyxo-5-hexulofuranosonic acid · H2O (3), and -α-D-arabino-5-hexulofuranosonic acid · H2O (4). The compounds 1-4 were characterized by analytical and 13C-NMR spectroscopic data. At pH 6.5 they split quantitatively into the original compounds.
    Notes: In Methanol erhält man aus D-gluco- bzw. D-galacto-konfigurierten 2-Amino-2-desoxyhexosen sowie Hexuronsäuren die Amadori-Verbindungen 6-(2-Desoxy-α-D-glucopyranos-2-ylamino)-6-desoxy-β -D-lyxo-5-hexulofuranosonsäure (1) und -α-D-arabino-5-hexulofuranosonsäure (2) sowie 6-(2-Desoxy-D-galactopyranos-2-ylamino)-6-desoxy-β-D- lyxo-5-hexulofuranosonsäure · H2O (3) und -α-D-arabino-5-hexulofuranosonsäure · H2O (4). Die Verbindungen 1-4 werden durch elementaranalytische und 13C-NMR-spektroskopische Daten charakterisiert. Bei pH 6.5 zerfallen sie fast quantitativ unter Rückbildung der eingesetzten Ausgangsverbindungen.
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  • 42
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1702-1714 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thioketene Syntheses, II1). - Formation of Thioketenes from Alkylidenephosphoranes and Carbon DisulfideThe alkylidenephosphoranes 3a-c react with carbon disulfide (4) to give the dipoles 5a-c. Starting from phosphoranes 3 with bulky (3d) or aryl substituents (3e) secondary reactions occur in situ. Products detected in these reactions as well as in the thermolysis of 5a-c are triphenylphosphane sulfide (8), triphenylphosphane (15), and the trithiepins 16a, b. Amines 18 as trapping reagents for the potentially occurring thioketenes 9 react with 5a to afford the thioamides 19b-d. Trapping reactions with azomethines 22 lead to the β-thiolactam 24, the thiazetidines 25, and the hexahydropyrimidinethiones 26. According to product analysis, it seems that not the thioketenes 9, but the thioketenoid intermediates 7 are intercepted in the trapping reactions.
    Notes: Die Alkylidenphosphorane 3a-c treten mit Kohlenstoffdisulfid (4) zu den Dipolen 5a-c zusammen. Ausgehend von Phosphoranen 3 mit sterisch anspruchsvoller (3d) oder Aryl-Substitution (3e) laufen in situ Folgereaktionen ab. Dabei lassen sich wie auch bei der Thermolyse von 5a-c Triphenylphosphansulfid (8), Triphenylphosphan (15) und die Trithiepine 16a, b nachweisen. Amine 18 als Abfangreagenzien für die potentiell auftretenden Thioketene 9 führen mit 5a zu den Thioamiden 19b-d. Abfangreaktionen mit Azomethinen 22 ergeben das β-Thiolactam 24, die Thiazetidine 25 und die Hexahydropyrimidinthione 26. Nach der Produktanalyse sind als Reaktionspartner der Abfangreagenzien nicht die Thioketene 9, sondern die Thioketenoiden Zwischenstufen 7 wahrscheinlich.
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  • 43
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 612-616 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2-Nitrocyclohexanone by Nitration of Cyclohexanone with Highly Concentrated Nitric Acid2-Nitrocyclohexanone (1) is important as an intermediate in the synthesis of Caprolactam and as a short-lived intermediate in the large-scale production of adipic acid from cyclohexanol and concentrated (ca. 68%) nitric acid. We have succeeded in preparing 1 by reaction of cyclohexanone with highly concentrated (99-100%) nitric acid. It was possible to isolate 1 by working at 20-400C in inert solvents and by almost completely preventing its further reaction to adipic acid by means of short reaction times, incomplete cyclohexanone and nitric acid conversion and stopping the reaction sequence by addition of ice/water.
    Notes: 2-Nitrocyclohexanon (1) besitzt als Zwischenprodukt einer Caprolactam-Synthese und als kurzlebige Zwischenstufe bei der großtechnischen Herstellung von Adipinsäure aus Cyclohexanol und konzentrierter (ca. 68proz.) Salpetersäure Bedeutung. Es gelang, Cyclohexanon mit hochkonzentrierter (99- bis 100proz.) Salpetersäure zu 1 umzusetzen. Die Verbindung 1 konnte isoliert werden, wenn man bei 20-400C in inerten Lösungsmitteln arbeitete und die Weiterreaktion von 1 zu Adipinsäure durch kurze Reaktionszeiten, unvollständigen Cyclohexanon- und Salpetersäure-Umsatz und Abbruch der Reaktionsfolge mit Eis/Wasser weitgehend verhinderte.
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  • 44
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 617-627 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enamines, XVII. Addition of aromatic Acyl Chlorides to β-disubstituted EnaminesAromatic acyl chlorides react with β-disubstituted enamines at different rates to give (2-aroylalkyliden)ammonium chlorides 2. Acid hydrolysis of 2 yields 2-aroylaldehydes 3, while basic hydrolysis gives alkyl aryl ketones 6. On reaction with triethylammonium azide and Cyclohexyl isocyanide 2c loses the aroyl group to form 8.
    Notes: Aromatische Carbonsäurechloride setzen sich unterschiedlich rasch mit β-verzweigten Enaminen zu (2-Aroylalkyliden)ammoniumchloriden 2 um. Saure Hydrolyse von 2 führt zu den 2-Aroyl-aldehyden 3, alkalische zu den Alkylarylketonen 6. Mit Triethylammoniumazid und Cyclohexylisocyanid reagiert 2c unter Verlust des Aroylrestes zu 8.
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  • 45
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 639-649 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemistry of 1,2,4-Triazepines, XIV. - Condensations of β-Dicarbonyl Compounds with 1,2-Diaminoimidazoles
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  • 46
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 628-638 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Nitro Compounds from Tetraalkylammonium NitritesPrimary or secondary bromoalkanes and 2-bromo carbonyl compounds give the nitro derivatives 2, 5 and 7 on reaction with tetraalkylammonium nitrites 1 in dichloromethane or acetonitrile at -50 to 200C. The ratio of nitroalkane and alkyl nitrite (2/3) in the reaction of 1-bromoheptane with the salt 1a in various solvents is investigated. 1,1'-(1,3-Phenylene)dipyrrolidine (6) is a good scavenger for alkyl nitrites.
    Notes: Durch Umsetzung von primären oder sekundären Bromalkanen und 2-Bromcarbonylverbindungen mit Tetraalkylammoniumnitriten 1 in Dichlormethan oder Acetonitril bei -50 bis 200C erhält man die Nitroverbindungen 2, 5 und 7. Das Nitroalkan/Alkylnitrit-Verhältnis (2/3) in verschiedenen Lösungsmitteln wird an der Umsetzung von 1-Bromheptan mit dem Salz 1auntersucht. 1,1'-(1,3-Phenylen)dipyrrolidin (6) eignet sich zum Abfangen der Alkylnitrite 3.
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  • 47
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 650-655 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermal and Photochemical Reactions of New Mesoionic 1,3-Oxazol- and 1,3-Thiazol-5-onesThe preparation of the mesoionic 1,3-oxazol-5-one 2 and of the 1,3-thiazol-5-one 4, both substituted with donor and acceptor groups, and their reactions with water or methanol are described Compound 2 combines with dimethyl acetylenedicarboxylate at 1200C with formation of the pyrroledicarboxylic ester 6 (6%) as a result of a [3 + 2]-cycloaddition reaction. Photochemically, 4 undergoes ring-opening to the ketene 9, which reacts with methanol to give the ester 10.
    Notes: Die Darstellung des mit Donor- und Akzeptorgruppen substituierten mesoionischen 1,3-Oxazol-5-ons 2 und des 1,3-Thiazol-5-ons 4 sowie ihre Reaktionen mit Wasser oder Methanol werden beschrieben. Mit Acetylendicarbonsäure-dimethylester vereinigt sich 2 bei 1200C zum Pyrroldicarbonsäureester 6 (6%) als Ergebnis einer [3 + 2]-Cycloaddition. Photochemisch erleidet 4 Ringöffnung zum Keten 9, das mit Methanol zum Carbonsäureester 10 reagiert.
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  • 48
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 675-688 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cycloaddition Reactions with Azabenzenes, XIII. - Reactions of 1,2.4,5-Tetrazines with FulvenesDepending on the conditions, reaction of 6-dialkylaminofulvenes 1 with 3,6-diphenyl-1,2,4,5-tetrazine (2a) affords 5-dialkylaminomethylene-1,4-diphenyl-5H-cyclopenta[d]pyridazines 10a-d, 3,6-diphenylpyridazine (12), 4-(2-dimethylaminovinyl)-3,6-diphenylpyridazine (13), 9-dimethylaminomethylene- 1,4,5,8-tetraphenyl-4a,4b,8a,9a- tetrahydro-9H-cyclopenta[1,2-d:3,4-d]dipyridazine (14), and 9-dimethylaminomethylene-1,4,5,8-tetraphenyl -9H-cyclopenta-[1,2-d:3,4-d]dipyridazine (15). Compounds 10a and 10b are easily hydrolyzed, yielding 1,4-diphenyl-2-H-cyclopenta[d]pyridazine-5-carbaldehyde (11a) and 1-(1,4-diphenyl-2-H-cyclopenta[d]pyridazine-5-yl)ethanone (11b), respectively. The structures of compounds 10 and 12-15 were determined by spectroscopic methods, chemical reactions or synthesis by an independent route.
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  • 49
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleosides, XXX1). - Synthesis and Properties of 4-N-Benzoyl-O-(tert-butyldimethylsilyl)-cytidines**4-N-Benzoylcytidine (1) has been silylated by tert-butyldimethylsilyl chloride to give the possible mono- (5, 13, 14), di- (6, 7, 10), and tri-O-tert-butyldimethylsilyl ethers (8), the structures of which were characterized by chemical and spectrophotometric methods. 13C-NMR spectroscopy proved to be a simple and fast method for determining the silylation positions. The 2-O- and 3-O-tert-butyldimethylsilyl derivatives undergo base-catalyzed interconversion especially in alcohols.
    Notes: Ausgehend von 4-N-Benzoylcytidin (1) werden durch Silylierung mit tert-Butyldimethylsilylchlorid die möglichen Mono- (5, 13, 14), Di- (6, 7, 10), und Tri-O-tert-butyldimethylsilylether (8) dargestellt und die Strukturen auf chemischem und spektroskopischem Wege gesichert. 13C-NMR- Spektroskopie erlaubt eine einfache und rasche Festlegung der Silylierungspositionen. Die 2′-O-und 3′-O-tert-Butyldimethylsilyl-Derivate unterliegen einer gegenseitigen Isomerisierung, die insbesondere in Alkoholen beobachtet wird und basenkatalytisiert ist.
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  • 50
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1881-1889 
    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-3-Phenoxyproline**Allylic bromination of the 1,2-dehydroproline ester 4 and reaction of the resulting bromoimine 3 with thallium phenolate affords 3-phenoxy-1,2-dehydroproline methyl ester (9). Reduction experiments with 9 and 10 are described, which lead in the most favorable case to a mixture of the corresponding cis/trans-isomeric prolines 11a and 11b in a ratio of 2:3. A “one-pot” procedure starting from 3 is described for the preparation of 7a.
    Notes: Allylbromierung des 1,2-Dehydroprolinesters 4 und Umsetzung des entsprechenden Bromimins 3 mit Thalliumphenolat gibt den 3-Phenoxy-1,2-dehydroprolin-methylester (9). Reduktionsversuche an 9 sowie 10 werden beschrieben und führen im günstigsten Fall zu einer Mischung der entsprechenden cis/trans-isomeren Proline 11a und 11b im Verhältnis 2:3. Ausgehend von 3 wird eine“Eintopf”-Reaktion zur Darstellung von 7a beschrieben.
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  • 51
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1908-1914 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of 2-Haloethoxycarbonyl Compounds with Tertiary Phosphanes(2-Bromoethoxycarbonyl)amino acids 1 including the sarcosine derivatives 13 and 15 react with methyldiphenylphosphane to give the 2-phosphonioethoxycarbonyl derivatives, which are cleaved under mild basic conditions to yield the corresponding free amino compounds. The same transformation of the protective group was not successful in the case of the 2-bromoethoxycarbonyl protected alcohols 3, phenols 4, secondary amines 11 and 12 and the analogous 2-bromoethyl esters of amino acids and peptides; these compounds furnish the ethylene-1,2-bisphosphonium salt 6.
    Notes: (2-Bromethoxycarbonyl)aminosäuren 1, einschließlich der Sarkosin-Derivate 13 und 15, reagieren mit Methyldiphenylphosphan zu den 2-Phosphonioethoxycarbonyl-Verbindungen, welche unter milden basischen Bedingungen zu den freien Aminoverbindungen gespalten werden. Die gleiche Schutzgruppenumwandlung gelingt an 2-Bromethoxycarbonyl-geschützten Alkoholen 3. Phenolen 4 und den sekundären Aminen 11 und 12 sowie an Aminosäure- und Peptid-(2-bromethylestern) nicht. In diesen Fällen bildet sich das Ethylen-1,2-bisphosphoniumsalz 6.
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  • 52
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemistry of Aromatic Nitrocompounds, XIV.  -  Triplet Sensitization and Quenching of Photocyclization of 1,4-Di-tert-butyl-2-nitrobenzene.The photocyclization 1a → 4a may be sensitized by benzophenone and triphenylene with an efficiency very similar to that of direct photolysis of 1a. The product quantum yield Φp for formation of 4a via direct photolysis of 1a in alcoholic solutions is suppressed by 21% with air-oxygen and by max. 16% with octafluoronaphthalene. 1,3-Pentadiene ist effective as a quencher only when present in high concentrations (1 - 3 M). The results suggest that the photocyclization 1a* → 4a mainly proceeds from the first excited singlet state of 1a.
    Notes: Die Photocyclisierung 1a → 4a läßt sich mit Benzophenon und Triphenylen sensibilisieren, der dabei erreichte Wirkungsgrad ist dem der direkten Photolyse annähernd gleich. Die Produktquantenausbeute Φp für die durch direkte Photolyse von 1a in alkoholischer Lösung induzierte Bildung von 4a wird durch Luftsauerstoff um 21%, durch Octafluornaphthalin um maximal 16% gesenkt. 1,3-Pentadien löscht merklich nur in hoher Konzentration (1 - 3 M). Die Ergebnisse sprechen dafür, daß die Photocyclisierung 1a* → 4a überwiegend vom untersten angeregten Singulettzustand von 1a ausgeht.
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  • 53
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1992-2004 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Chloromethyl Methyl Ether with Chlorin DerivativesReactions of chloromethyl methyl ether with the methine bridge carbon atom 20 and the 3-vinyl group of chlorin derivatives pyropheophorbide a methyl ester 1, [3-ethyl]-pyropheophorbide a methyl ester (10) and [3-ethyl]-chlorin e6 trimethyl ester (13)〉 are described. The 20-hydroxymethyl group introduced into 13 could be reduced to methyl group with palladium/hydrogen. - The structure of the reaction products are proved by mass- and 1H-NMR spectra.
    Notes: Es werden Reaktionen von Chlormethyl(methyl)ether mit dem Methinbrücken-Kohlenstoffatom 20 und der 3-Vinylgruppe von Chlorin-Derivaten 〈 Pyrophäophorbid-a-methylester (1), [3-Ethyl]-pyrophäophorbid-a-methylester (10) und [3-Ethyl]-chlorin-e6-trimethylester (13)〉 beschrieben. Die in 13 eingeführte 20-Hydroxymethylgruppe konnte mit Palladium/Wasserstoff in eine Methylgruppe umgewandelt werden. - Durch Massen- und 1H-NMR-Spektren werden die Strukturen der Reaktionsprodukte belegt.
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  • 54
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 2005-2010 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Nitriles, LVI.  -  A Novel Facile Synthesis of 4-Aminosalicylic Acid and Isophthalic Acid DerivativesTreatment of malonodinitrile with triethyl orthoformate affords ethoxymethylenemalonodinitrile, which reacts with alkyl β-oxocarboxylates to yield the substituted 4-aminosalicylates 4a - c. Acid or basic hydrolysis of the nitrile and ester groups of 4a - c leads to the new derivatives 5a, 7a - c, 8a - c, and 9a of 4-aminosalicylic acid. The isophthalic acid derivatives 6a - c are obtained by basic hydrolysis of 4a - c.
    Notes: Aus Malonsäuredinitril und Orthoameisensäure-triethylester erhält man Ethoxymethylenmalonsäuredinitril, welches mit β-Oxocarbonsäureestern zu den substituierten 4-Aminosalicylsäure-estern 4a - c reagiert. Durch saure oder alkalische Hydrolyse der Nitril- und Estergruppen von 4a - c entstehen die neuen Derivate 5a, 7a - c, 8a - c und 9a der 4-Aminosalicyclsäure; allein durch alkalische Hydrolyse erhält man die Isophthalsäurederivate 6a - e.
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  • 55
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 829-841 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions and Cyclizations in the Reactions of Ynamines with KetenesYnamines 1a-e with alkyl, aryl, acyl, and phosphino groups at the acetylenic β-carbon atom add diphenylketene (2a) and the aldoketenes 2b-d to yield in all cases the allenecarboxamides 4a-i besides the cyclobutenones 5a-i. The β-naphthyl diphenylacetate 7 is isolated as by-product on reaction of 1c with 2a. The ynamines 1f-h, bearing phosphoryl groups, add diphenylketene 2a to yield the cyclobutenones 5j-I and the cyclization products 9a-c. The naphthols 9a and 9b bearing phosphoryl and phosphorimidoyl groups exhibit strong intramolecular hydrogen bonding, shown by their reactions and their spectroscopic data. Diazomethane transformed 9a and 9b into the corresponding methyl naphthyl ethers 10, while diphenylketene effected acylation of 9a to 11. The allenecarboxamides 4j-I are synthesized by treatment of the phosphino derivative 4i with hydroperoxide, sulfur, and p-toluenesulfonyl azide, respectively.
    Notes: Die Inamine 1a-e mit Alkyl-, Aryl-, Acyl- und Phosphinresten am β-Kohlenstoffatom bilden mit Diphenylketen (2a) und den Aldoketenen 2b-d in allen Fällen Allencarboxamide 4a-i neben den Cyclobutenonen 5a-i. Als Nebenprodukt wird bei der Umsetzung von 1c mit 2a das β-Naphthyl-diphenylacetat 7 isoliert. Die Phosphorylgruppen tragenden Inamine 1f-h liefern mit 2a neben den Cyclobutenonen 5j-I die Cyclisierungsprodukte 9a-c. Die beiden Naphthole 9a und 9b mit der Phosphoryl- bzw. der Phosphorimidoyl-Gruppierung besitzen starke intramolekulare Wasserstoffbrückenbindungen, wie deren Reaktionen und spektroskopische Daten zeigen. Mit Diazomethan werden 9a und 9b in die entsprechenden Methylnaphthylether 10 übergeführt, während 9a mit Diphenylketen acyliert wird. Die Allencarboxamide 4j-I lassen sich aus dem Phosphin-Derivat 4i mit Hydroperoxid, Schwefel bzw p-Toluolsulfonylazid synthetisieren.
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  • 56
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 858-865 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ligand Structure and Complexation, XLV. - New Crown Ether EstersThe synthesis and properties of the new cyclic and non-cyclic crown ether type ligands 1-15 are described. They contain carboxylic and squaric ester units. Their ligand character has been proven by isolating crystalline complexes with sodium and potassium salts. With KSCN, 15 does not yield the expected ester complex (18), but the complex 19 of the diphenol 17.
    Notes: Synthese und Eigenschaften der neuen cyclischen und offenkettigen Neutralliganden 1-15 des Kronenethertyps, die Carbonsäure-oder Quadratsäureester-Gruppen enthalten, werden beschrieben. Die Ligandeigenschaften wurden durch Isolierung kristalliner Komplexe mit Natrium- und Kaliumsalzen nachgewiesen. 15 liefert mit KSCN nicht den erwarteten Komplex 18 des Esters, sondern den Komplex 19 des Diphenols 17.
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  • 57
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Steroidal Compounds of Phosphorus, VII1). -Dimethylphosphinates and Dimethylthiophosphinates of HydroxysteroidsHydroxysteroids 1a-7a are converted in high yields into the dimethylphosphinates 1b-7b by dimethylphosphinic chloride or N,N-(dimethyl)dimethylphosphinic amide. Dimethylthiophosphinic chloride reacts uniformly and completely in presence of triethylamine to give the corresponding dimethylthiophosphinates 1c-7c, 8, and 9.
    Notes: Hydroxysteroide1a-7a werden durch Dimethylphosphinsäurechlorid oder N,N-(Dimethyl)-dimethylphosphinsäureamid mit hohen Ausbeuten in die Dimethylphosphinsäureester 1b-7b übergeführt. Dimethylthiophosphinsäurechlorid reagiert in Gegenwart von Triethylamin einheitlich und vollständig zu den entsprechenden Dimethylthiophosphinsäureestern 1c-7c, 8 und 9.
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  • 58
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Indole, XII1). - Syntheses of Compounds Similar to Eserine, III; New Derivatives of Deoxyeseroline Substituted at N-1 and N-8 and a Novel Synthesis of EseretholeTreatment of the ethyl 3-methyl-4-phenylhydrazonobutanoates 1 with HCI/ethanol gives the furoindolones 2 in good yields. Reaction of 2 with primary amines furnishes the pyrroloindolones 3 without by-products. Furthermore, reactions of 2 with complex hydrides and with Grignard compounds are described. Eserethole (4e) has been obtained in quantitative yield by reaction of 2g with LiAIH4.
    Notes: Die Behandlung der 3-Methyl-4-phenylhydrazonobutansäure-ethylester 1 mit HCI/Ethanol liefert in guten Ausbeuten die Furoindolone 2. Die Reaktion von 2 mit primären Aminen ergibt ohne Nebenprodukte die Pyrroloindolone 3. Weiterhin werden Umsetzungen von 2 mit komplexen Hydriden und mit Grignard-Verbindungen beschrieben. Aus 2g erhält man mit LiAIH4 in quantitativer Ausbeute Eserethol (4e).
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  • 59
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 944-949 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Cyanide Ions with α,β-Unsaturated Esters, II1). - Reactions of Ethyl Acrylate and MethacrylateAction of sodium cyanide on ethyl acrylate (1a) and ethyl methacrylate (1b) yields ethyl 2-cyano-3-oxocyclopentanecarboxylates 6a and 6b, respectively. From these were obtained the 3-oxocyclopentanecarboxylic acids 7a and 7b, respectively, and from 7b the isomeric methyl esters 81 and 82 which were separated by distillation.
    Notes: Einwirkung von Natriumcyanid auf Acrylsäure-ethylester (1a) und Methacrylsäure-ethylester (1b) führt zu den 2-Cyan-3-oxocyclopentancarbonsäure-ethylestern 6a bzw. 6b. Daraus erhielt man die 3-Oxocyclopentancarbonsäuren 7a bzw. 7b und aus 7b die isomeren Methylester 81 und 82, die destillativ getrennt wurden.
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  • 60
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic 12-π- and 14-π-Systems, 34. - Experiments on the Reactivity of 2-Phenyl-5H-naphtho[1,8-bc]furan-5-one (Oxapseudophenalenone)Reactions of 2-phenyl-5H-naphtho[1,8-bc]furan-5-one (1) with perchloric acid in alcohols yield the 4-alkoxy-8-hydroxy-1-naphthyl phenyl ketones 3a-3c which are also obtained from 4,8-dihydroxy-1-naphthyl phenyl ketone (2) in acidic alcoholic solutions. Diphenylketene, naphthylphenylketene, tert-butylcyanoketene, cyanomethylketene, cyanophenylketene react with 1 to give the 2-phenyl-oxapseudophenafulvenes 4-8; thermolysis of 2,5-diazido-3,6-dioxo-1,4-cyclohexadiene-1,4-dicarbonitrile (9) yields in situ the dicyanoketene (10) which reacts with the ketone 1 via elimination of CO2 to give the (2-phenyl-oxapseudophenafulven-5-ylidene)malonodinitrile 11. Compound 11 was not obtained by another route.
    Notes: Die Reaktionen von 2-Phenyl-5H-naphtho[1,8-bc]furan-5-on (1) mit Perchlorsäure in Alkoholen führen zu den (4-Alkoxy-8-hydroxy-1-naphthyl)(phenyl)ketonen 3a-3c, die auch aus (4,8-Dihydroxy-1-naphthyl)(phenyl)keton (2) in sauren alkoholischen Lösungen zugänglich sind. Mit Diphenylketen, Naphthylphenylketen, tert-Butylcyanketen, Cyanmethylketen, Cyanphenylketen werden die 2-Phenyl-oxapseudophenafulvene 4-8 erhalten, mit dem durch Thermolyse von 2,5-Diazido-3,6-dioxo-1,4-cyclohexadien-1,4-dicarbonitril (9) in situ erzeugten Dicyanketen (10) wird unter Eliminierung von CO2 das auf anderen Wegen nicht zugängliche (2-Phenyl-oxapseudophenafulven-5-yliden)malonodinitril 11 synthetisiert.
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  • 61
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic 12-π- and 14-π-Systems, 36. - Synthesis and Reactivity of 3-Hydroxy-2H-naphtho[1,8-bc]thiophen-2-one - an Iso-π-electronic peri-9-Hydroxyphenalen-1-oneReaction of 2-methoxybenzo[b]thiophene with cinnamoyl chloride in the presence of AICI3 yields 2-methoxybenzo[b]thiophen-3-yl α-styryl ketone (1a). 2-Bromobenzo[b]thiophene and cinnamoyl chloride or 2-bromobenzo[b]thiophen-3-yl methyl ketone (1b) and benzaldehyde yield 2-bromobenzo[b]thiophen-3-yl α-styryl ketone (2). Compound 1a reacts in aqueous ethanolic solution to give 3 and the reaction products 4 and 5 were isolated by cyclisation of 2; 3-hydroxy-2H-naphtho[1,8-bc]thiophen-2-one (6) was obtained from 4 and methanolic sodium hydroxide. Reaction of 6 with Co++ and Ni++ salts leads to the complexes 7a and 7b; alkylation with dialkyl sulfate furnishes the derivatives 8a and 8b, and alkylation with the “Meerwein salt” triethyloxonium tetrafluoroborate affords the 2,3-diethoxy (thiapseudophenalenium) salt 9. We obtained the thione compound 10 from 8b and P2S5; methylation of 10 with CH3I gave the 3-ethoxy-2-methylthio (thiapseudophenalenium) salt 11. We synthesized the thiapseudophenafulvene 12 from 10 and 11 under various conditions.
    Notes: Die Reaktion von 2-Methoxybenzo[thiophen mit Zimtsäurechlorid in Gegenwart von AICI3 ergibt (2-Methoxybenzo[b]thiophen-3-yl)(α-styryl)keton (1a), aus 2-Brombenzo[b]thiophen mit Zimtsäurechlorid oder ausgehend von (2-Brombenzo[b]thiophen-3-yl)(methyl)keton (1b) mit Benzaldehyd wird (2-Brombenzo[b]thiophen-3-yl)(α-styryl)keton (2) erhalten. 1a geht in wäßrig-ethanolischer Lösung in 3 über und durch Cyclisierung von 2 werden als Reaktionsprodukte 4 sowie 5 isoliert. Durch Behandlung von 4 mit methanolischer Natronlauge wird 3-Hydroxy-2H-naphtho[1,8-bc]thiophen-2-on (6) erhalten. Die Verbindung 6 bildet sehr leicht mit Co++- und Ni++-Salzen die Komplexe 7a bzw. 7b, durch Alkylierung mit Dialkylsulfat werden die Derivate 8a sowie 8b, durch weitere Alkylierung mit “Meerweinsalz” das 2,3-Diethoxy(thiapseudophenaleniumsalz) 9 erhalten. Aus 8b entsteht mit Phosphorpentasulfid die Thion-Verbindung 10, durch Methylierung von 10 mit CH3I das 3-Ethoxy-2-methylthio(thiapseudophenaliumsalz) 11, während aus 10 sowie 11 unter verschiedenen Bedingungen das Thiapseudophenafulven 12 synthetisiert wurde.
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  • 62
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereoselective Synthesis of 2′-Substituted 2-Vinylcyclopropanecarboxylic Acids and -carbaldehydes; Preparation of Homologues of the Seaweed Pheromone EctocarpeneVersatile and sterically unequivocal syntheses are described for derivatives of 2-(1-alkenyl)cyclopropanecarboxylic acid and -carbaldehyde as intermediates in the preparation of 1,2-bis(1-alkenyl)cyclopropanes and substituted 1,4-cycloheptadienes. Starting from ethyl trans-2-formyl-cyclopropanecarboxylate (13) they lead to 1,2-cyclopropanedicarbaldehyde (18), protected on one side, which may undergo stepwise olefinations. The advantages of using these bifunctional cyclopropane compounds are that few synthetic steps are involved, the products are easily separated, and good yields are obtained. By this method, we have prepared inter alia the natural products dictyopterenes 1-3 with cyclopropane structure and ectocarpene (4) with 1,4-cycloheptadiene structure. The possibility of separating them from their diastereomers are described.
    Notes: Variationsfähige und sterisch eindeutige Synthesen von Derivaten von 2-(1-Alkenyl)cyclopropan-carbonsäure und -carbaldehyd als Zwischenstufen für die Darstellung von 1,2-Bis(1-alkenyl)-cyclopropanen und substituierten 1,4-Cycloheptadienen wurden ausgearbeitet. Sie gehen aus von trans-2-Formylcyclopropancarbonsäure-ethylester (13) und führen über einseitig geschützten 1,2-cyclopropandicarbaldehyd (18), der stufenweise olefiniert werden kann. Die Vorteile der Verwendung derartiger bifunktioneller Cyclopropanderivate sind die geringe Zahl von Syntheseschritten bei guten Ausbeuten sowie die unproblematische Trennung der Zwischenprodukte. Unter anderem werden alternative Wege zu den Cyclopropan- und 1,4-Cycloheptadien-Naturstoffen, wie den Dictyopterenen 1-3 und Ectocarpen (4) beschrieben und Möglichkeiten zur Trennung von deren Diastereomeren angegeben.
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  • 63
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 997-1001 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of N-Alkyliminobis(thiocarbaldehydes)N-Methyl- (2a) and N-ethyliminobis(thiocarbaldehyde) (2b), and their hydrochlorides 4, were prepared by reaction of the corresponding N-alkylbis(dichloromethyl)amines 3 with hydrogen sulfide. Their properties and spectroscopic data are reported. Compound 2a reacts with antimony(V) chloride to give a 1:1 adduct.
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  • 64
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations on Diazo Compounds and Azides, XXXII. - Substitution Reactions at the Diazo Carbon of Diazomethylphosphoryl Compounds
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  • 65
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Components of the Green Deathcap Toadstool Amanita phalloides, LVI1). - Recyclization of Secophalloidin and Secophallisin to the Toxic Parent Compounds and Non-toxic-DiastereomersThe secolactones 2a and 2b obtained by mild acidic hydrolysis from phalloidin (1a) or phallisin (1b), respectively, are transformed into the zwitterionic seco compounds 3a and 3b on passing through a column of Sephadex LH-20 in 0.004N ammonium hydroxide. After activation of the carboxyl groups of 3a or 3b by reaction with isobutyloxycarbonyl chloride, the mixed anhydrides so formed lead under reformation of the peptide ring to the original toxins 1a and 1b, respectively, and also to the diastereomeric peptides 4a and 4b in which the π-hydroxylated amino acids have D-configuration. These D-amino acid-containing analogs are non-toxic in doses up to 50 mg per kg body weight of the white mouse. Their difference UV spectra with and without actin differ markedly from those of the toxic phallotoxins.
    Notes: Die durch milde Säurehydrolyse aus Phalloidin (1a) oder Phallisin (1b) erhältlichen Secolactone 2a und 2b werden durch Passieren einer Säule von Sephadex LH-20 in 0.004 N Ammonium-hydroxid-Lösung in die Secozwitterionen 3a bzw. 3b verwandelt. An diesen gelingt nach Aktivierung als gemischte Anhydride mit Isobutyloxycarbonylchlorid die Recyclisierung zu den Muttersubstanzen 1a und 1b. Die nebenbei entstehenden, chromatographisch abtrennbaren, isomeren bicyclischen Peptide 4a und 4b werden als Diastereomere von 1a bzw. 1b erkannt, die sich durch die D-Konfiguration der π-hydroxylierten Aminosäure Nr. 7 von 1a und 1b unterscheiden. Diese Diastereomere sind bis 50 mg pro kg an der weißen Maus ungiftig, ihre UV-Differenzspektren mit und ohne Actin unterscheiden sich von denen der giftigen Phallotoxine.
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  • 66
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangement of 4-(Tetrahydrocarbazol-9-yl)- and 4-(Tetrahydrocyclopent[6]indol-4-yl)-3-buten-2-oneThe N-substitution products 1 and 9b of tetrahydrocarbazole and of tetrahydrocyclopentindole with acetylacetaldehyde dimethyl acetal react in methanolic hydrochloric acid to give besides the cyclisation product 12 under rearrangement the ketone 2a and the ketones 6a and 10a with pro-pellane structure. The compounds 12 and 10a as well as 6a and 2a are shown to be in equilibrium. The reaction course and the spectra are discussed. - Compound 2a is hydrogenated to 3a, which can be isolated in two stereoisomeric forms corresponding to cis- and trans-decalone. The benzoyl derivative 3g formed by hydrogenation has the same constitution as the appropriately modified product obtained by Fischer cyclisation from trans-α-decalone. - The rearrangement products 2a, 6a and 10a, as well as the corresponding saturated ketones 3a, 7a and 11, are transformed into derivatives by reaction at the oxo and amino function. Furthermore, 2a gives the benzylidene derivative 4 while 3a furnishes the benzylidene derivative 5a and the cinnamylidene derivative 5b.
    Notes: Die mit Acetylacetaldehyd-dimethylacetal gebildeten N-Substitutionsprodukte 1 und 9b des Tetrahydrocarbazols und Tetrahydrocyclopentindols reagieren in methanolischer Salzsäure außer zum Cyclisierungsprodukt 12 unter Umlagerung zum Keton 2a sowie zu den Ketonen 6a bzw. 10a mit Propellanstruktur. Für die Verbindungen 12 und 10a sowie für 6a und 2a wird ein Gleichgewicht nachgewiesen. Der Reaktionsverlauf und die Spektren werden erörtert. - Die Verbindung 2a wird zum gesättigten Keton 3a hydriert, das in zwei stereoisomeren Formen, dem cis- und trans-Decalon entsprechend, gefaßt wird. Das durch Hydrierung gewonnene Benzoylderivat 3g besitzt die gleiche Konstitution wie das durch Fischer-Reaktion aus transα-Decalon gewonnene und entsprechend abgewandelte Produkt. - Die Umlagerungsprodukte 2a, 6a und 10a sowie die entsprechenden gesättigten Ketone 3a, 7a und 11 werden durch Umsetzung an der Oxo- und Aminogruppe in Derivate übergeführt. Außerdem liefert 2a das Benzylidenderivat 4 und 3a das Benzylidenderivat 5a sowie das Cinnamylidenderivat 5b.
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  • 67
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1067-1080 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Photoreductions of NitroisoalloxazinesNitration of 3,10-dimethylisoalloxazine (1b) yields the 7-nitro derivative 2b. Nitration of 3,7,10-trimethylisoalloxazine (1c) gives the 6- and 9-mononitro compounds in a ratio of 2c:2d = 97:3, from 3,7,8,10-tetramethylisoalloxazine, the 6- and 9-nitro and the 6,9-dinitro derivatives are obtained in a ratio of 2g:2h:2i = 76:8:1. Riboflavine (1h) yields only the 6-mononitro derivative 2k. - 8-Nitroisoalloxazine 2n is obtained from the 8-amino derivative 3a via the diazonium salt 4a. Mild nitration of 1,3,7,8-tetramethylalloxazine (5b) yields the 6- and 9-mononitro derivatives 5d and 5f, respectively. - On photoreduction of the 6- and 8-nitroisoalloxazines in the presence of ethylenediaminetetraacetic acid, the corresponding hydroxylamino derivatives 7b and a, respectively, are formed which can be reoxidized by hexacyanoferrate(III). Continued photoreduction gives the amino derivatives. 9-Nitroisoalloxazines 2h is photoreduced only to the 1,5-dihydro-9-nitro compound 6a, which is reoxidized by oxygen.
    Notes: Die Nitrierung von 3,10-Dimethylisoalloxazin (1b) ergibt das 7-Nitroderivat 2b. Aus 3,7,10-Trimethylisoalloxazin (1c) entstehen dabei das 6- und 9-Mononitroderivat im Verhältnis von 2c:2d = 97:3, aus 3,7,8,10-Tetramethylisoalloxazin (1f) das 6-, 9-Nitro- und das 6,9-Dinitroderivat im Verhältnis von 2g:2h:2i = 76:8:1. Riboflavin (1h) ergibt ausschließlich die 6-Mononitroverbindung 2k. - Die Synthese des 8-Nitroisoalloxazins 2n ist aus der 8-Aminoverbindung 3a über das Diazoniumsalz 4a möglich. Vorsichtige Nitrierung von 1,3,7,8-Tetramethylalloxazin (5b) ergibt ein Gemisch des 6- und 9-Mononitroderivats 5d bzw. 5f. - Bei der Photoreduktion der 6- und 8-Nitroisoalloxazinderivate in Gegenwart von Ethylendiamin-tetraessigsäure entstehen zunächst die entsprechenden Hydroxylaminoverbindungen 7a und b, die durch Hexacyanoferrat(III) zu den Nitroderivaten reoxidiert werden; fortgesetzte Photoreduktion ergibt die Aminoverbindungen. Das 9-Nitroisoalloxazin 2h wird nur zur 1,5-Dihydro-9-nitro-Stufe 6a photoreduziert, die durch Sauerstoff zur Ausgangsverbindung reoxidierbar ist.
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  • 68
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1112-1115 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Limits in the Addition of Dichlorocarbene to Sterically Demanding OlefinsSterically crowded tetrasubstituted olefins do not react with CCl2. - New dichlorocyclopropanes 1, 2, 5, 6, 7, and 10 are described. 2 rearranges to 3 and 4 even at 65 ° C in vacuo.
    Notes: Sterisch stark behinderte tetrasubstituierte Olefine reagieren nicht mit Dichlormethylen. - Die neuen Dichlorcyclopropane 1, 2, 5, 6, 7 und 10 werden beschrieben. 2 lagert sich bereits bei 65 ° C im Vakuum in 3 und 4 um.
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  • 69
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1102-1111 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crown Ethers With Different Pharmacophoric GroupsThe preparation of drug crown ethers with different ion selectivities is described. Apart from crown ether amines with acetylsalicyl-, p-aminobenzoyl-, trimethoxycinnamoyl-, phenothiazine-and other substituents several barbiturates as well as papaverine, eupaverine, isoproterenol, and orciprenaline derivatives with intramolecular crown ether units have been synthesized. A crystalline complex of ligand 22 with Ca(SCN)2 and containing 1 mol H2O has been obtained.
    Notes: Die Darstellung von Arzneimittel-Kronenethern mit unterschiedlicher Ionenselektivität wird be-schrieben. Außer Kronenetheraminen mit Acetylsalicyl-, p-Aminobenzoyl-, Trimethoxycinnamoyl-, Phenothiazinylresten und anderen Substituenten wurden verschiedene Barbiturate sowie Papaverin-, Eupaverin-, Isoproterenol- und Orciprenalin-Abkömmlinge mit intramolekularen Kronenethereinheiten synthetisiert. Von dem Liganden 22 wurde ein kristalliner Komplex mit Ca(SCN)2 erhalten, der 1 mol H2O enthält.
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  • 70
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    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 71
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    Gamete Research 2 (1979), S. 35-42 
    ISSN: 0148-7280
    Keywords: activated motility ; temperature dependence of motility ; sperm transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The motility of rabbit spermatozoa recovered from the vagina, endocervix, uterus, and four regions of the oviduct was assessed visually by phase-contrast microscopy at intervals from one minute to 16 hours after a single mating. The percentage of motile cells in each sample was dependent on the temperature of recovery, ie, 23° vs 37°C, but was not influenced by the temperature of observation. Spermatozoa in the lower isthmus of the oviduct were the most temperature sensitive population to recovery at 23°C. When all manipulations and observations were performed at 37°C, the percentage of spermatozoa with progressive motility varied according to the region sampled and interval after mating. Populations from the vagina, uterus and upper regions of the oviduct usually had a high proportion of progressively motile cells with vigorous flagellar activity. Fewer spermatozoa showed progressive movement on recovery from the endocervix and lower 2 cm of the tubal isthmus and their flagellar activity was generally depressed. The decrease in flagellar beat frequency noted in the latter regions may be a major factor limiting sperm ascent in the female tract. A unique pattern of “activated” motility was seen exclusively in populations taken from the oviducts at 6 to 16 hours after mating. This motility pattern, consisting of alternating episodes of linear progressive and vigorous nonprogressive movement, may be analogous to the activated motility described for capacitated rodent spermatozoa.
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  • 72
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    Gamete Research 2 (1979), S. 75-87 
    ISSN: 0148-7280
    Keywords: acrosin ; activation ; inhibitor ; proacrosin ; spermatozoa ; zymogen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The sperm-specific proteinase acrosin (EC 3.4.21.10) is found in spermatozoa as a zymogen. We have looked for different forms of this zymogen in testicular, epididymal, and ejaculated spermatozoa from ram and have compared total sperm extracts made immediately after cell disruption with extracts made later from isolated sperm heads. We have concluded that the autoactivatable zymogen form, known generally as proacrosin, is the only form of acrosin within intact mature ram spermatozoa; no other zymogen form was detected, although lower levels of proacrosin were found in some samples of testicular spermatozoa. From studies of the activation process, it appears that ram proacrosin is truly autoactivatable; no evidence could be found for the involvement of any auxiliary enzyme. Estimations of the molecular weight of proacrosin using gel chromatography (60,000) and SDS-polyacrylamide gel electrophoresis (51,300) indicated that the zymogen is monomeric. Comparison with the molecular weight of ram acrosin (44,000 or 40,000, using the two respective methods) indicated that a single acrosin molecule is derived from each zymogen molecule. The sperm acrosin inhibitor (molecular weight 11,000 or 8,000) was present in testicular spermatozoa as well as in ejaculated spermatozoa; there was no evidence that it was produced as a result of zymogen activation.
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  • 73
    ISSN: 0148-7280
    Keywords: spermatozoon-ostracoda (Heterocypris incongruens) ; external morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In various papers on the original spermatozoon of the Ostracoda, its helicoidal disposition has been indicated as the principle characteristic of this gamete, at cell structure level as well as in its external morphology. Through a combined study with scanning electron microscope (SEM) and transmission electron microscope (TEM), we have been able to establish the corresponding relationship between the cell architecture and the spermatozoon's external morphology. In the case of Heterocypris incongruens, the helicoidal relief of the gamete's external surface along the greatest part of its length, is the result of the twisting and undulating of a structure derived from the nucleus' external membrane, endoplasmic reticulum, and Golgi apparatus, called “feather-like organelle.” In keeping with the shape of this surface relief, the spermatozoon can be divided into three regions: An anterior one with a corkscrew form, a middle one showing a relief in the form of a screw with four threads, and a posterior or tail one without helicoidal relief. Finally, we discuss the different criteria existing on the possible orientation of this spermatozoon when it moves, as well as the functional advantages that the possession of a filiform, helicoidal, and mobile gamete represents.
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  • 74
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    Gamete Research 2 (1979), S. 121-124 
    ISSN: 0148-7280
    Keywords: oocyte maturation ; LH ; ovum culture ; germinal vesicle breakdown ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Immature rats, aged 27 days, were stimulated to develop preovulatory follicles by subcutaneous injection of 15 IU of pregnant mare serum gonadotrophin (PMSG). Two days later their oocytes were collected. They were cultured under conditions that permitted continuous observation. Times of the initial stages of maturation were carefully noted, in the absence and the presence of 10 μg/ml of bovine luteinizing hormone (LH). LH did not accelerate germinal vesicle disappearance. It was concluded that the immature PMSG-treated rat was not an appropriate model for the study of LH action; it was speculated that persistence of PMSG mimicked LH in all the oocytes from such donors.
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  • 75
    ISSN: 0148-7280
    Keywords: lysin ; protease inhibitor ; sea urchin ; vitelline coat ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To search the spermatozoa of sea urchins for their lysins, the eggs were inseminated in the presence of various protease inhibitors. Among them, two chymotrypsin-specific inhibitors, chymostatin and N-tosyl-L-phenylalanyl-chloro-methane, as well as p-nitrophenyl p′-guanidinobenzoate, inhibit fertilization of the sea urchins, Hemicentrotus pulcherrimus and Strongylocentrotus intermedius.A chymotrypsin-like protease is presumed to be a lysin of the sea urchins, since the inhibition of fertilization by chymostatin is remarkably diminished if the eggs are pretreated with trypsin or chymotrypsin to break the vitelline coat before insemination, and since N-tosyl-L-phenylalanyl-chloromethane, and p-nitrophenyl p′-guanidinobenzoate, as well as chymostatin, inhibit the fertilization.In all the sea urchins so far studied, elevation of fertilization envelopes is inhibited by leupeptin, antipain, soybean trypsin inhibitor, and p-nitrophenyl p′-guanidinobenzoate, all of which are potent trypsin inhibitors.Synthetic inhibitors have cytotoxic side effects on the eggs, but the microbial and plant inhibitors have no such effects.
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  • 76
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    Gamete Research 2 (1979), S. 223-233 
    ISSN: 0148-7280
    Keywords: seminal plasma DNase ; nicked sperm DNA ; sperm decondensation ; DNA template ; DNA phosphorylation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Ejaculated rabbit spermatozoa washed with buffer prior to decondensation by Triton X-100 and dithiothreitol were good templates for DNA synthesis by Escherichia coli DNA polymerase. This result agrees with the observations of Zirkin and Chang [1977], and implies that the sperm DNA is nicked. Template activity, however, was reduced if spermatozoa were extensively washed before decondensation, and if DNase inhibitors EDTA or Na2SO4 were present during decondensation. Template activity was also low if decondensation was induced with DNase inhibitors thioglycollic acid, Na2SO3 or sodium dodecylsulphate and dithiothreitol instead of with Triton X-100 and dithiothreitol. Calf thymus DNA was completely degraded when incubated with rabbit seminal plasma or buffer-washed spermatozoa, but much less degradation was observed if EDTA, Na2SO4, thioglycollic acid, Na2SO3 or sodium dodecylsulphate were also present, or if spermatozoa were extensively washed with buffer. Centrifugation of spermatozoa through 2.05 M sucrose completely removed contaminating DNase, and such spermatozoa were inactive as DNA templates after decondensation. The DNA template activity of swollen rabbit sperm nuclei thus parallels the activity of a contaminating seminal plasma DNase. This suggest that the nicks in sperm DNA enabling it to act as a template for DNA synthesis were generated by the DNase during decondensation and thus are not a natural structural feature of the DNA. The presence of breaks in the DNA of decondensed buffer-washed spermatozoa (DNase contaminated) was confirmed by their incorporation of phosphate from [γ-32 P] ATP in the presence of the enzyme polynucleotide kinase. These spermatozoa were found to contain as few as two breaks/mole of DNA, but sucrose-washed spermatozoa (DNase free) were free of breaks. The possible use of this enzymic procedure for the assessment of sperm genome damage and the evaluation of the quality of a sperm population are discussed.
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  • 77
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    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 78
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    Gamete Research 2 (1979), S. 265-282 
    ISSN: 0148-7280
    Keywords: sperm chromatin ; nuclease digestion ; sperm decondensation ; chromatin structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The structure of rabbit, fowl, and Xenopus laevis sperm chromatin was explored by study of the reaction of their decondensed nuclei with DNase 1 and micrococcal nuclease. Those of rabbit and fowl were readily digested by DNase 1, and the polyacrylamide gel electrophoresis profiles of DNAs extracted from the digests were similar, each being polydisperse with a single discrete band of DNA smaller than 72 base pairs. There were differences, however, between the sperm chromatins in the course of their digestion by micrococcal nuclease. A limit digest at about 45% acid solubility was obtained with Xenopus sperm chromatin, while 90% of fowl sperm DNA was rendered acidsoluble by the enzyme. The gel profiles of the limit digests were polydisperse, but only those of rabbit and fowl sperm chromatins possessed a discrete band of DNA smaller than 72 base pairs. Bleomycin did not react with DNA of rabbit, fowl, or Xenopus spermatozoa. Since bleomycin reacts with somatic cell chromatin, and the course of DNase 1 or micrococcal nuclease digestion of sperm chromatin was different from that found for somatic cell chromatin, it would appear that sperm chromatin does not have the repeating nucleosometype structure of somatic cell chromatin. The nuclease digestion studies further suggest that the organization of rabbit and fowl sperm chromatins is similar, and is different from that of Xenopus sperm chromatin. The dependence of the structure of sperm chromatin on the composition of its basic proteins, and a possible structure for a protamine-type sperm chromatin, are discussed.
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  • 79
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    Gamete Research 2 (1979), S. 295-304 
    ISSN: 0148-7280
    Keywords: in vitro fertilization ; mouse ; sperm penetration ; zona pellucida ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Sperm penetration through the zona pellucida and fusion of the sperm head with the vitellus were observed continuously and filmed under phase optics in cumulus-free living mouse eggs inseminated in vitro with capacitated epididymal sperm. Most spermatozoa penetrated the zona pellucida, traversed the perivitelline space, and fused with the vitellus at an angle nearly perpendicular to the surface. The mean duration required for sperm to penetrate the zona pellucida was 20 minutes with a range of 15-26 minutes. Sperm traversed the perivitelline space in less than one second. The initial contact of sperm with the vitellus generally took place at the tip of the sperm head. When the tip of the sperm head contacted the vitellus there was an immediate reduction in the rate of flagellation, followed by the gradual sinking of the sperm head into the vitellus.
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  • 80
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    Gamete Research 2 (1979), S. 357-366 
    ISSN: 0148-7280
    Keywords: ova ; spermatozoa ; cryopreservation ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mature unfertilized ova from superovulated hamsters were freed from all investments and frozen at -50°C. They were cooled at about 1°C/min to 0°C then at 0.8° to 0.6°C/min to -50°C. At 0°C, dimethyl sulfoxide was added to a final concentration of 1.25 M. The ova were stored at -50°C for up to four months. Thawing was performed at 2-4°C/min and followed by several washes with insemination medium. Approximately 90% of the ova were normal in appearance after thawing. The frozen and thawed ova with normal appearance could be penetrated by hamster or human spermatozoa at a rate comparable to unfrozen controls. The ability of hamster ova to tolerate storage at a relatively convenient temperature (-50°C) for long periods (tested for up to four months) makes possible their shipment at low cost to institutions lacking this resource. There they can be used for basic biological studies of sperm-egg interaction or in the clinical assessment of human sperm quality.
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  • 81
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    Liebigs Annalen 1979 (1979), S. 866-869 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Olefins via Light-induced Fragmentations of Thietanes with a New SensitizerThe fragmentations of the spirothietanes 1 or 5a-d, induced with visible light in the presence of the 2-thioparabanate 4 as a triplet sensitizer, proceed with formation of the highly substituted ole-fin derivatives 2 or 6a-d, respectively.
    Notes: In Gegenwart der 2-Thioparabansäure 4 als neuem Triplett-Sensibilisator führen die bereits mit sichtbarem Licht induzierten Fragmentierungen der Spirothietane 1 oder 5a-d in glatter Reaktion zu den hochsubstituierten Olefin-Abkömmlingen 2 bzw. 6a-d.
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  • 82
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    Liebigs Annalen 1979 (1979), S. 121-132 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 13C-NMR Investigations of 2-Cyclohexenones and 2,5-CyclohexadienonesProton noise decoupled 13C-NMR spectra of 26 2-cyclohexen-1-ones and 2,5-cyclohexadien-1-ones have been measured. The unequivocal assignment of the spectra was achieved with the aid of proton off-resonance decoupled spectra and by selective deuteration. Moreover, it became evident that assignments reported in the literature were wrong and need to be corrected. Effects of various substituents in position 4 of the system as well as solvent effects are discussed. The 13C-values of the carbonyl carbon of all cyclohexenones and cyclohexadienones proved to be of diagnostic value for both of these ring systems, often occurring in nature.
    Notes: Von 26 2-Cyclohexen-1-onen und 2,5-Cyclohexadien-1-onen wurden die 1H-breitbandentkoppelten 13C-NMR-Spektren aufgenommen. Die eindeutige Zuordnung der Signale erfolgte durch 1H-Off-Resonance-Entkopplung sowie durch selektive Deuterierung. Dabei zeigte sich, daß Zuordnungen in der Literatur falsch getroffen wurden und korrigiert werden müssen. Die Substituenteneinflüsse verschiedener sich in 4-Stellung befindlicher Reste sowie Lösungsmitteleffekte werden daneben diskutiert. Die13C-Resonanzen der Carbonylkohlenstoffatome von Cyclohexenonen und Cyclohexadienonen erwiesen sich als diagnostisch für jedes dieser beiden in der Natur häufig vorkommender Ringsysteme.
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  • 83
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    Liebigs Annalen 1979 (1979), S. 102-120 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vinylamines, XXII.-Solvent Dependence of Imine-Enamine-TautomerismThe imine ⇌ enamine equilibria of 35 tautomeric compounds in [D5]bromobenzene and [D5]-nitrobenzene can be described very strictly by a linear free energy relationship. The investigation of seven selected compounds in seven solvents of different polarity shows this to be a common principle. With the less polar solvent [D6]benzene as standard a group of straight lines with a common point of intersection results. They all show a positive slope and intercept. Thus polar solvents favour the enamine tautomer. The solvent effect is high in the case of compounds existing largely in the enamine form and becomes very low in the case of compounds having a high imine content. The enthalpies and entropies of reaction-determined from the temperature dependence of the equilibria-show that the solvent effect can generally be described by an isothermodynamic relationship. It is compensatory (β = 506 K) in character and controlled by enthalpy changes (β 〉 Texp.).
    Notes: Die Gleichgewichte Imin ⇌ Enamin von 35 tautomeren Verbindungen in [D5]Brombenzol und [D5]Nitrobenzol gehorchen einer linearen Freie-Enthalpie-Beziehung hoher Präzision. Die Untersuchung von sieben ausgewählten Verbindungen in sieben Lösungsmitteln unterschiedlicher Polarität zeigt, daß es sich um ein allgemeines Prinzip handelt. Mit dem am wenigsten polaren Lösungsmittel [D6]Benzol als Standard erhält man eine Schar von Geraden mit positiver Steigung, positivem Ordinatenabschnitt und einem gemeinsamen Schnittpunkt. Polare Lösungsmittel begünstigen also das Enamin. Der Lösungsmitteleffekt ist bei hohen Enaminanteilen am größten und geht bei hohen Iminanteilen gegen Null. Die aus der Temperaturabhängigkeit der Gleichgewichte bestimmten Reaktionsenthalpien und Reaktionsentropien zeigen, daß der Lösungsmitteleffekt allgemein durch eine isothermodynamische Beziehung kompensatorischer Art (β = 506 K) mit Enthalpiekontrolle (β 〉 Texp.) beschrieben werden kann.
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  • 84
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopropanimines, IV.-α-BromoketiminesThe synthesis of α-bromoketimines is achieved in two ways which complement each other. At low temperature, the reaction of α-bromoimidoyl chlorides 3 with Grignard reagents affords good yields of N-alkyl- and N-aryl-α-bromoketimines 4 in an unequivocal way with respect to the position of the bromine atom. In contrast, the N-(tert-butyl)bromo-tert-butylketenimine 6 reacts unexpectedly via substitution of the bromine.-Bromination of the N-tert-butylketimines 9, derived from methyl ketones, by N-bromosuccinimide or by 2,4,4,6-tetrabromocyclohexadienone occurs largely regioselectively at the methyl group. On warming the primary bromination products undergo (presumably acid-catalysed) isomerization and disproportionation to give equilibrium mixtures in which the bromoketimines having the bromine atom at the more highly substituted α-position predominate.-The reaction of the N-tert-butylimine of tetramethylcyclohexanone 10 with tetrabromocyclohexadienone yields a mixture of tautomeric monobromo compounds. In contrast, under all conditions tried bromine reacts to give only the α-α'-dibromoenamine 17. For steric reasons, this reacts exclusively at the nitrogen atom with protons or excess bromine.-The structures of all compounds are confirmed by IR and 1 H-NMR spectra, from which conclusions are also drawn concerning the preferred configuration and conformation.
    Notes: Die Synthese von α-Bromketiminen gelingt auf zwei Wegen, die sich ergänzen. Umsetzung der α-Bromimidoylchloride 3 mit Grignard-Verbindungen bei tiefer Temperatur ergibt eindeutig bezüglich der Stellung des Bromatoms in guten Ausbeuten die N-Alkyl- und N-Aryl-α-bromketimine 4. Das N-(tert-Butyl)brom-tert-butylketenimin 6 reagiert dagegen unerwartet unter Substitution des Broms.-Die Bromierung der N-tert-Butylketimine 9, die sich von Methylketonen ableiten, mit N-Bromsuccinimid oder 2,4,4,6-Tetrabromcyclohexadienon erfolgt weitgehend regioselektiv an der Methylgruppe. Aus den primären Bromierungsprodukten erhält man beim Erwärmen durch (vermutlich säurekatalysierte) Isomerisierung und Disproportionierung Gleichgewichtsgemische, in denen die Bromimine 13 mit dem Bromatom an der höhersubstituierten α-Stellung stark überwiegen.-Das N-tert-Butylimin des Tetramethylcyclohexanons 10 liefert mit dem Tetrabrom-cyclohexadienon ein Tautomerengemisch von Monobrom-Verbindungen, mit Brom dagegen stets nur das α-α'-Dibromenamin 17. Aus sterischen Gründen reagiert dieses mit Protonen oder überschüssigem Brom nur noch am Stickstoff.-Die Strukturen der Verbindungen werden durch IR-und 1H-NMR-Spektren gesichert, aus denen auch Rückschlüsse auf die bevorzugte Konfiguration und Konformation abgeleitet werden.
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  • 85
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    Liebigs Annalen 1979 (1979), S. 142-143 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Note on the Thermal Rearrangement of O-Benzoyl-N-methyl-N-[2-( methylthio)phenyl]hydroxylamineThe thermal rearrangement of O-benzoyl-N-methyl-N-[2-(methylthio)phenyl] hydroxylamine (1) to 2-(methylaminocarbonyl)phenylthiomethyl benzoate (2) is described.
    Notes: Die thermische Umlagerung von O-Benzoyl-N-methyl-N-[2-(methylthio)phenyl] hydroxylamin (1) in Benzoesäure-[2-(methylaminocarbonyl)phenylthiomethylester] (2) wird beschrieben.
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  • 86
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    Liebigs Annalen 1979 (1979) 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 87
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    Liebigs Annalen 1979 (1979), S. 145-149 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bridged Tetraphenylene Systems, II.-On the Structure of 4,11-Dihydrodicyclopenta[def, pqr]-tetraphenylene and Its Dilithium DerivativeIt follows from the 1 H-NMR data of the doubly methano-bridged tetraphenylene 1that this compound has a nonplanar structure. This also holds for the 4,11-dilithium derivatives, 3which reacts with iodine to give undefined polymeric products.
    Notes: Aus den 1H-NMR-Daten des zweifach Methano-verbrückten Tetraphenylens 1 folgt, daß diese Verbindung einen nichtplanaren Bau besitzen muß. Gleiches gilt für das 4,11-Dilithium-Derivat 3, das mit lod zu undefinierten polymeren Produkten reagiert.
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  • 88
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Configuration of Diastereomeric 9-Methylcarbazole CompoundsA synthetic route including Reformatsky and Curtius reactions has been used for the preparation of the diastereomeric ß-hydroxyesters 1a, b, hydroxyhydrazides 4a, b, oxazolidones 6a, b and 8c-e, amino alcohols 7a -e and some related compounds in good yields. The relative configurations of 1a, b have been determined by a thin-layer chromatographic method. The configuration and conformation of the diastereomeric carbazole derivatives have been studied by1H-NMR and IR spectroscopy.
    Notes: Es wurden Reformatsky- und Curtius-Reaktionen von Carbazol-Derivaten untersucht, wobei mit guten Ausbeuten diastereomere ß-Hydroxydrazide, 4a b, Oxyzolidone 6a b und 8c-e,ß -Aminoalkohole 7a-e wie auch einige verwandte Verbindungen erhalten wurden. Die Konfigurationen von 1a, b wurden mit einer dünnschichtchromatographischen Methode be-stimmt. Konfiguration und Konformation der Diastereomeren wurden .1H-NMR- und IR-spektroskopisch ermittelt.
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  • 89
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Flavonoids, XXXIV.-Nucleophilic Substitution in 3-(Alkyl- and 3-(Arylsulfonyloxy)-favanones; a New Method for Synthesis of 3-AminoflavenonesTeilweise vorgetragen auf dem 5. Ungarischen Bioflavonoid-Symposium, Matrafüred, 1977; vgl.: T. Patonay, M. Rdkosi, Gy. Litkel, T. Mester und R. Bognár in Flavonoids and Bioflavonoids, Current Research Trends, Proceedings of the 5th Hungarian Bioflavonoid Symposium, M átrafured, 25-27 May 1977 (L. Farkas, M. Gábor und F. Kallay), S. 227, Akadémiai Kiado, Budapest und Elsevier, Amsterdam 1977.3-Hydroxyflavanones 1-4 and 3-hydroxyflavenone (14) react with alkane- and arenesulfonyl chlorides giving the corresponding 3-sulfonates 5-8, 10-13 and 15-20, respectively. 3-(Tosyl-oxy)flavanone (9)cannot be obtained. On reaction with azide ions, the 3-(methysulfonyloxy)fla-vanones 5-8 give the 3-azidoflavanones 25-28 with azide ions, which transform into the 3-aminoflavenones 21-24 in a base-induced, secondary reaction. The corresponding reaction is accompanied by a (3-elimination leading to flavenones 29-32. The ratio of products 21-24 29-32 is determined by the R1-substituent of ring B of the starting compounds 5-8. 3-Azidoflavanone (25) can be isolated on quenching of the reaction; compound 25 gives 3-aminoflavanone (36) and 3-(triphenylphosphoranediylamino)flavenone (39) on catalytic hydrogenation and treatment with triphenylphosphine, respectively.
    Notes: Die Umsetzungen der 3-Hydroxyflavanone 1-4 und des 3-Hydroxyflavenons (14) mit Alkan- und Arensulfonsäruechloriden liefern die entsprechenden 3-Sulfonate 5-8, 10-13 bzw. 15-20 Das 3-(Tosyloxy)flavanon (9) läßt sich nicht auf diese Weise herstellen. Die 3-(Methylsulfonyloxy)flavanone 5-8 bilden mit Azidionen 3-Azidoflavanone 25-28, die sich in einer baseninduzierten Sekundärreaktion zu 3-Aminoflavenonen 21-24 umsetzen. Daneben entstehen die ent sprechenden Flavenone 29-32. Das Produktverhältnis 21-24 29-32 wird durch den Substituenten R1 am Ring B der Ausgangsverbindungen 5-8bestimmt. Durch frühzeitigen Abbruch der Reaktion läßt sich das 3-Azidoflavanon (25) isolieren, das durch katalytische Hydrierung in das 3-Aminoflavanon (36) und mit Triphenylphosphin in das 3-(Triphenylphosphorandiylamino)-flavenon (39) übergeführt wird.
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  • 90
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    Liebigs Annalen 1979 (1979), S. 174-180 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Flavonoids, XXXV1.-Synthesis of α-Azido-2′-oxychalcones and Their Transformation into 3-AminoflavenonesTeilweise vorgetragen auf dem 5. Ungarischen Bioflavonoid-Symposium. Mátrafüred, 1977; vgl.: T. Patonay, M. Rákosi, Gy. Litkei, T. Mester und R. Bogná in Flavonoids and Bioflavonoids, Current Research Trends, Proceedings of the 5th Hungarian Bioflavonoid Symposium, Mátrafüred, 25-27 May 1977 (L. Farkas, M. Gábor und F. Kállay), S. 227, Akadémia Kiadó, Budapest und Elsevier, Amsterdam 1977.The regioselective reaction of the benzylacetophenone dibromides 5a-d with sodium azide in dimethylformamide affords a 9:1 mixture of α-azido-2′-oxychalcones 4a-dand isoxazoles 7a, b, d. On treatment with bases 4a and4d are transformed into 3-aminoflavenone (11), whereas 4b gives the same product with acid. 4a-c give 2′-oxy-a-(triphenylphosphoranediylamino)chalcones 14a-c with triphenylphosphine, whereas 4d yields 2,3-trans-3-(triphenylphophoranediylamino)-flavanone (15) under the same conditions.
    Notes: In einer regioselektiven Reaktion werden aus den Benzylacetophenondibromiden 5a-d mil Natriumazid in Dimethylformamid die α-Azido-2′-oxychalkone 4a-d und Isooxazole 7a, b und dim Verhältnis 9:1 hergestellt. Aus 4a und d erhält man mit Basen und aus 4b mit Sauren 3-Aminoflavenon (11). Mit Triphenylphosphin bilden 4a-c die 2′-Oxy-a-(triphenylphosphorandiylamino)chalkone 14a-c, während 4d 2,3-trans 25-3-(Triphenylphosphorandiylamino)flavanon (15) liefert.
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  • 91
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    Liebigs Annalen 1979 (1979), S. 194-199 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: E,Z-Rearrangements of 2,3-Dichloroacrylic Acid Derivatives and Synthesis of E,Z-2-Bromo-4,5-dichloro-2,4-pentadienoic AcidThe configuration of the stereoisomeric acrylic acids 1a and 2a is confirmed by 13C-NMR spectroscopic investigations. Rearrangements E-Z, probably due to the cis-effect of the chlorine atoms in Z-isomers, were observed in the preparation of the acid chloride 1d from 2a and the aldehyde 1f from 2d and 2g.-The synthesis of the pentadienoic acid 5 from 1f via 3 and 4 is described.
    Notes: Die Konfiguration der stereoisomeren Dichloracrylsäuren 1a und Za wird durch 13C-NMR-spektroskopische Untersuchungen festgelegt. Umlagerungen E-*Z die wahrscheinlich durch den cis-Effekt der Chloratome in den Z-Isomeren verursacht sind, wurden bei der Darstellung des Säurechlorids 1d aus 2a sowie der des Aldehyds If aus 2d und 2g beobachtet.-Die Synthese der Pentadiensäure 5 aus 1f über 3 und 4 wird beschrieben.
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  • 92
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    Liebigs Annalen 1979 (1979), S. 181-193 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyaddukts of Dihalocarbenes to Polyolefins and Experiments on Directed Partial DehalogenationPhase transfer catalysis permits the addition of up to 2 :CHal2 to pyrene, up to 3 :CHal2 to bullvalene, and up to 4 :CHal2 to cyclooctatetraene, However, the yields of higher adducts are low. Several reducing agents are used for partial dehalogenation of cyclooctatetraene adducts. Removal of several endo-bromine atoms in one step is possible most efficiently with tributyl tin hydride, but zinc/DMF shows high selectivity in some cases too. Removal of several endo-bromine atoms is achieved by halogen metal exchange at low temperature and subsequent methanolysis. In the case of the bisadduct 9b, there is a narrow temperature range in which alternative ring enlargement and immediate valence tautomerization to naphthalene can be avoided.
    Notes: Die Phasentransfer-Katalyse gestattet die Addition von bis zu 2 :CHal2 an Pyren, bis zu 3 :CHal2 an Bullvalen und bis zu 4 :CHal2 an Cyclooctatetraen. Jedoch sind die Ausbeuten niedrig. Verschiedene Reduktionsmittel wurden zur partiellen Enthalogenierung der Cyclooctatetraen-Addukte erprobt. Zur Entfernung mehrerer exo-Bromatome in einem Reaktionsschritt ist Tributylzinnhydrid am besten geeignet, aber auch Zink/DMF reagiert gelegentlich sehr selektiv. Die Entfernung mehrerer endo-Bromatome gelingt durch Halogen-Metall-Austausch bei tiefer Temperatur und anschließende Methanolyse. Beim Bisaddukt 9b gibt es einen engen Temperaturbereich, in dem die alternative Ringerweiterung und sofortige Valenztautomerisierung zu Naphtha-lin vermieden werden kann.
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  • 93
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 200-209 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Epoxide with Isocyanates, II1b)-Preparation and Characterization of 2-OxazolidinonesIsocyanates react with epoxides to yield 2-oxazolidinones. The reaction of isocyanates with un-symmetrically substituted epoxides 1 was studied in order to investigate differences in the direction of ring opening of the epoxides as a function of the type of catalyst (nucleophilic or electrophilic). With the exception of styrene oxides, where 4- and 5-substituted 2-oxazolidinones 4 and8 are formed, all other epoxides examined lead to 5-substituted 2-oxazolidinones, independent of the catalyst, e.g. 2a-c.
    Notes: Isocyanate reagieren mit Epoxiden zu 2-Oxazolidinonen. Um auf die Öffnungsrichtung des Epoxidringes in Abhängigkeit vom Katalysator (nucleophil oder elektrophil) schließen zu können, wurden Umsetzungen von Isocyanaten mit unsymmetrisch substituierten Epoxiden 1untersucht; dabei konnte festgestellt werden, daß nur aus Styroloxid auch in 4-Stellung substituierte2-Oxazolidinone 4 und 8 gebildet werden. Alle anderen untersuchten Epoxide führen unabhängig vom Katalysator ausschließlich zu 5-substituierten 2-Oxazolidinonen, z. B. 2a-c.
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  • 94
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 210-218 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Epoxides will Isocyanates, III-Study of 2-Oxazolidinones by Mass SpectrometryThe decomposition of 2-oxazolidinones in the mass spectrometer is initiated essentially by two steps: 1) Elimination of carbon dioxide by α-decomposition; 2) a-cleavage by liberation of carbon monoxide and of the corresponding aldehyde.-The 5-aryl-3-phenyl-2-oxazolidinones (e. g. 1) undergo both reactions at roughly equal rates. 5-Alkyl- or 5-alkylidene-3-phenyl-2-oxazolidi-nones (e. g.4, 5) preferentially eliminate carbon dioxide. The main degradation reaction of 4-aryl-3-phenyl-2-oxazolidinones (e. g. 2) is α-cleavage.
    Notes: Der Zerfall von 2-Oxazolidinonen im Massenspektrometer wird im wesentlichen durch zwei Primärschritte eingeleitet: 1) Abspaltung von Kohlendioxid durch p-Zerfall; 2) a-Spaltung unter Freisetzung von Kohlenmonoxid und dem entsprechenden Aldehyd.-Bei 5-Aryl-3-phenyl-2-oxazolidinonen (z. B. 1) vollziehen sich beide Reaktionen in gleichem Maße; 5-Alkyl- oder 5-Alkyliden-3-phenyl-2-oxazolidinone (z. B. 4, 5) spalten vorzugsweise Kohlendioxid ab. 4-Aryl-3-phenyl-2-oxazolidinone (z. B. 2) zeigen als Hauptreaktion die α-Spaltung.
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  • 95
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 219-226 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Lithium Alkynolates and Lithio KetenesLithium phenylalkynolate (7a) was obtained from 3,4-diphenylisoxazole (5a) via 3,4-diphenyl-5-isoxazolyllithium (5b). Compound 7a was trapped with chlorotrimethylsilane as phenyltrimethylsilylketene (8 a) and with aldehydes and ketones as p-lactones 11.-3-Phenylisoxazole (5c) afforded the dilithio ketene (8d) (lithium tetramethylpiperidide as metalating agent). 8d was trapped as bis(trimethylsilyl)ketene or bis(trimethylstannyl)ketene (8b or c).-Other heterocyclic precursors for lithium alkynolates were examined.
    Notes: Aus 3,4-Diphenylisoxazol (5a) erhielt man über 3,4-Diphenyl-5-isoxazolyllithium (5b) Lithiumphenylethinolat (1a). Dieses wurde mit Chlortrimethylsilan zu Phenyl(trimethylsilyl)keten (8a), mit Aldehyden und Ketonen zu ß-lactonen 11 umgesetzt.-Aus 3-Phenylisoxazol (5c) entstand (mit Lithium-tetramethylpiperidid als Metallierungsmittel) Dillithioketen (8d), das als Bis(tri-methylsilyl)- oder Bis(trimethylstannyl)keten (8b bzw. c) nachgewiesen wurde.-Andere hetero-cyclische Vorstufen für Lithiumalkinolate wurden erprobt.
    Additional Material: 1 Tab.
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  • 96
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1116-1121 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Constituents of Euphorbiaceae, Vl. - Three New 4-Deoxyphorbol Triesters from Euphorbia biglandulosa Desf.The new 4-deoxyphorbol triesters 13,20-O-diacetyl-12-O-(Z,E)-2,4-octadienoyl-4-deoxyphorbol (1), 20- O-acetyl-12-O-(Z,E)2,4-octadienoyl-13-O-propionyl-4-deoxyphorbol (2) and 20-O-acetyl-13-O-isobutyryl-12-O-(Z,E)-2,4-octadienoyl-4-deoxyphorbol (3) were isolated from the lipophilic phase of the latex sap of Euphorbia biglandulosa Desf. Their structure and that of the compounds 1a, 1b,2a and 3a formed on hydrolysis have been established by IR-, 1H-NMR- and mass spectroscopy. - The natural compounds have an irritating action on the skin of mice, a toxic on fishes and inhibit the oxidative phosphorylation of isolated heart mitochondria.
    Notes: Aus der lipophilen Phase des Milchsaftes von Euphorbia biglandulosa Desf. wurden 13,20-O-Diacetyl-12-O-(Z,E)-2,4-octadienoyl-4-desoxyphorbol (1), 20-O-Acetyl-12-O-(Z,E)-2,4-octa-dienoyl-13-O-propionyl-4-desoxyphorbol (2) und 20-O-Acetyl-13-O-isobutyryl-12-O-(Z,E)-2,4-octadienoyl-4-desoxyphorbol (3) isoliert. Die Strukturen dieser Verbindungen und ihrer Hydrolysederivate 1a, 1b, 2a,3a wurden durch IR-, 1H-NMR- und Massen-Spektroskopie belegt. -Die Substanzen 1-3 wirken als Fischgifte; sie sind hautätzend und hemmen die oxidative Phosphorylierung isolierter Herzmitochondrien.
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  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1125-1129 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and NMR Spectra of DiazadiphosphetidinesThe 1,3-diaza-2,4-diphosphetidines 4a-e are synthesized from tris(dialkylamino)phosphanes and aniline derivatives. Diphenyldiazomethane oxidizes a phosphorus atom in 4a to yield 5. The coupling constants JPf in 4 and 5 strongly suggest that P-F coupling occurs mainly through-space.
    Notes: Die 1,3-Diaza-2,4-diphosphetidine 4a -e werden durch Transaminierung aus Tris(dialkyl-amino)phosphanen und Anilinderivaten synthetisiert. Diphenyldiazomethan oxidiert in 4a ein Phosphoratom und führt zu 5. Die Kopplungskonstanten JPF legen nahe, daß die P - F-Kopplung hauptsächlich nach einem'through-space”-Mechanismus erfolgt.
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  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1137-1150 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions and Rearrangements During the Interaction of Hydrogen Bromide with AlkynesLiquid phase reactions of anhydrous hydrogen bromide with some alkynes were studied. In addition to products formed by conventional ionic and/or radical additions, 1-butyne (4a), 1-pentyne (4b), 1-hexyne (4c) and 3-cyclohexyl-1-propyne (4d) afforded in each case the corresponding cyclodimerization products 5 and/or 6 having 1,3-dialkyl-1,3-dibromocyclobutane structures. Under certain conditions 3,3-dimethyl-1-butyne (19) afforded 2,3-dibromo-2,3-dimethylbutane (28) and 1,3-dibromo-2,3-dimethylbutane (31). 2-Butyne (32) yielded four (33 - 36) of the five possible 1,3-dibromo-1,2,3,4-tetramethylcyclobutanes if HBr was used in excess, whereas the two stereo-isomeric 3-bromo-1,2,3,4-tetramethylcyclobutenes 38 and 39 were formed if a deficient amount of HBr was used.
    Notes: Die Flüssigphasenreaktionen von wasserfreiem Bromwasserstoff mit einigen Acetylenverbindungen wurden untersucht. Zusätzlich zu den durch konventionelle ionische und/oder radikalische Addition erhaltenen Produkten wurden aus 1-Butin (4a), 1-Pentin (4b), 1-Hexin (4c) und 3-Cyclohexyl-1-propin (4d) die entsprechenden Cyclodimeren 5 und/oder 6 mit 1,3-Dialkyl-1,3-dibromcyclobutanstrukturen gewonnen. Aus 3,3-Dimethyl-1-butin (19) entstanden unter be-stimmten Bedingungen 2,3-Dibrom-2,3-dimethylbutan (28) und 1,3-Dibrom-2,3-dimethylbutan (31). 2-Butin (32) lieferte mit überschüssigem HBr vier (33-36) der fünf möglichen 1,3-Dibrom-1,2,3,4-tetramethylcyclobutane und mit HBr im Unterschuß die beiden stereoisomeren 3-Brom-1,2,3,4-tetramethylcyclobutene 38 und 39.
    Additional Material: 5 Tab.
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  • 99
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentations with Supernucleophiles, VIII.  - Cleavage of β-Halogenated Urethanes by Co-balt(I)-phthalocyanine; a New Amino Protecting Group Technique for Peptide SynthesesHerrn Prof. Dr. Otto Bayer in Verehrung zum 75. Geburtstag gewidmet.A new protecting group technique, using ß-haloalkoxycarbonyl groups is presented and tested in two peptide syntheses. These protection groups are removed selectively and under mild conditions by the supernucleophilic cobalt(I)-phthalocyanine. The mechanism of this reaction consists in an alkylation step, followed by fragmentation.
    Notes: Eine neue Schutzgruppentechnik unter Verwendung von ß-Halogenalkoxycarbonyl-Gruppen wird vorgestellt und ihre Nützlichkeit anhand zweier Peptidsynthesen bewiesen. Die Abspaltung der Schutzgruppen erfolgt selektiv mit supernukleophilem Kobalt(I)-phthalocyanin über einen Alkylierungs-, Fragmentierungsmechanismus unter sehr schonenden Bedingungen.
    Additional Material: 9 Tab.
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  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1151-1172 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of a Membrane-Modifying Nonadecapeptide Analogue of AlamethicinThe following synthetic analogues of the membrane modifying peptide antibiotic alamethicin were obtained by fragment condensation: the nonadecapeptide Boc-(Aib-L-Ala)5-Gly-Ala-Aib-Pro-Ala-Aib-Aib-Glu(OBzl)-Gln-OMe (14a), its derivative 14b with free carboxyl group of glutamic acid in position 18, and the hexadecapeptide Boc-(Aib-L-Ala)5-Pro-Ala-Aib-Aib-Glu(OBzl)-Gln-OMe (13a). Mixed anhydride coupling with isobutyl chloroformate was most useful for the preparation of di- and tripeptide fragments, whereas larger fragments were coupled by the dicyclohexylcarbodiimide method with 1-hydroxybenzotriazene. The nonadecapeptide 14a was synthesized from the crystalline, analytically pure fragments A to D investigated by 13C-NMR and CD by a strategy based on considerations concerning the mode of action of alamethicin and its conformation. Boc-Aib1Ala-Aib-Ala-Aib5-OH (A, 8b) was condensed with H-Ala6-Aib-Ala-Aib-Ala10-OMe (B, 9c) and Boc-Gly11-Ala-Aib13-OH (C, 5b) with H-L-Pro14-Ala-Aib-Aib-Glu(OBzl)-Gln19-OMe (D, 10c). Finally the decapeptide 1-10 12b was coupled with nonapeptide 11 - 19 11c. - The hexadecapeptide 13a synthesized from the decapeptide 12b and fragment D,
    Notes: Als synthetische Analoga des membranmodifizierenden Peptidantibiotikums Alamethicin wur-den das Nonadekapeptid Boc-(Aib-L-Ala)5-Gly-Ala-Ala-Pro-Ala-Aib-Aib-Glu(OBzl)-Gln-OMe (14a), dessen Derivat 14b mit freier Glutaminsäure-Carboxylgruppe in Position 18 und das Hexadekapeptid Boc-(Aib-L-Ala)5-Pro-Ala-Aib-Aib-Glu(OBzl)-Gln-OMe (13a) durch Fragmentkondensation synthetisiert. Zur Darstellung von Di-und Tripeptidfragmenten bewährten sich besonders Kupplungen mit gemischten Anhydriden aus Chlorkohlensäure-isobutylester, während größere Fragmente durch Dicyclohexylcarbodiimid/1-Hydroxybenzotriazol-Kupplungen verknüpft wurden. Aufgrund von Vorstellungen über die Wirkungsweise von Alamethicin und dessen Konformation wurde das Nonadekapeptid 14a aus den kristallinen, analytisch reinen und durch 13C-NMR- sowie CD-Spektroskopie untersuchten Fragmenten A bis D wie folgt aufgebaut: Boc-Gly11-Ala-Aib-Ala-Aib5-OH (A, 8b) wurde mit H-Ala6-Aib-Ala-Aib-Ala10-OMe (B, 9c) und Boc-Gly11-Ala-Aib13-OH (C, 5b) mit H-Pro14-Ala-Aib-Aib-Glu(OBzl)-Gln19-OMe (D, 10c) verknüpft. Schließlich wurde das Dekapeptid 1 - 10 12b mit dem Nonapeptid 11 - 19 11c gekuppelt. - Das aus dem Dekapeptid und Fragment D synthetisierte Hexadekapeptid 13a ist inaktiv. Das Nonadekapeptid 14a besitzt eine hämolytische Aktivität wie Alamethicin und zeigt bei Bilayer-Experimenten eine spannungsabhängige Porenbildung in Form von “bursts”.
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