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1

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Masthead (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982)

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650101

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Stoffwechselprodukte von Mikroorganismen. 210. Mitteilung.209.Mitt. s. [1]. Über die Avilurekanosen A and C and weitere Abbauprodukte Avilamycine A and C (1982)

Kupfer, Ernst ; Neupert-Laves, Katarina ; Dobler, Max ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 3-12

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The Avileurekanoses A and C and Further Degradation Products of the Avilamycins A and CAlkaline hydrolysis of the orthosomycin antibiotics, avilamycins A ad C products similar t those earlier described for flambamycin. Among these avileurekanose c (15) became of particular importance because its acetate prisms suitable for an X-ray structural determination. For the avilamycins A and C structural formulae 2 and 3, respectively, can now be drawn, in which only the configuration at C (16), one out of 32 asymmetric C-atoms, is not yet determined.

Additional Material: 1 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19820650103

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Transition metal ions and amides. VIII.Part VIII, see [1]; Part VI, see [2]. Discrimination between different models for the complexation of Cu2+ with N, N′-diglycyl 1, 2-ethanediamine, N, N′-diglycyl-1, 3-propanediamine and glycine ethylamide by potentiometric or by spectrophotometric titration (1982)

Briellmann, Markus ; Zuberbühler, Andreas D.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 46-54

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The complexation of Cue2+ with 1, 8-diamino-3, 6-diaza-2, 7-octanedione (—N, N′-diglycyl-1, 2-ethanediamine, DED) and with 1, 9-diamino-3, 7-diaza-2, 8nonanedione (—N, N′-diglycyl-1, 3-propanediamine, DPD) has been studied by potentiometric and by spectrophotometric titration. With both ligands L the complexation to Cue2+ leads to relatively complicated equilibria with CuLH3+, CuL2+, CuLH-2, and dimeric Cu2L24+ complexes. With DED, another dimeric species, Cu2L2H-22+, is formed in addition. Independent numerical treatment of spectrophotometric and poteritiometric titrations was used to obtain a satisfactory model for the complexation and to test the relative discriminatory power of the two methods. Titrations of glycine ethylamide (GEA) were used as an additional test and as a model for DED and DPD. It was shown that in each case spectrophotometric titrations give results of similar reproducibility and have a discriminatory power equal to or better than potentiometric titrations, provided that optimum mathematical algorithms are used in the numerical treatment.

Additional Material: 3 Tab.

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URL: http://dx.doi.org/10.1002/hlca.19820650106

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Heterocyclische und carbocyclische 12-π- and 14-π-Molekü:lsysteme, 47. Mitteilung46. Mitt. s.[1]. Herstellung von 7, 9-Dimethyl-4, 5-dihydro-3 H-benz [cd]- azulen-3-on and 7,9-Dimethyl-3H-benz [cd]azulen-3-on. Eine einfache Synthese eines AzulenopseudophenalenonsTeilweise vorgetragen von R. Neidlein 1980 an den Departments of Chemistry der Universitäten Berkeley/Calif., Cambridge/Mass. (Harvard-Universität), Cambridge (England), East-Anglia/Norwich, Erlangen (Institut für Angewandte Chemie), Haifa (1978), Houston/Texas, Jerusalem (1978), Imperial Chemical Industries Ltd., Manchester, London (University College, Chelsea College), Manchester (Institute of Science and Technology), Oxford (England), Salford, Tübingen. (1982)

Neidlein, Richard ; Kramer, Walter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 280-285

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Heterocyclic and Carbocyclic 12-π-and 14-π-Systems, 47th Commnunication1. Synthesis of 7,9-Dimethyl-4,5-dihydro-3H-benz[cd]azualene-3-one and 7,9-Dimethyl-3H-benz[cd]azulene-3-one. A Simple Synthesis of Azulenopseudophenalenons4, 6, 8-Trimethylazulene (3) reacts after metalation with lithiumdiisopropyl-amide in ether with bromoacetic acid to the 6, 8-dimethylaltulene-4-propionic acid (4), which undergoes cyclization to the 7, 9-dimethyl-4, 5-dihydro-3H-benz [cd]-azulene-3-one (5) in the presence of p-toluenesulfonic acid; oxidation of 5 with 2, 3-dichloro-5, 6-dicyanobenzoquinone yields 7, 9-dimethyl-3H-benz [cd]azulene-3--one (1b). Alkylation of 1b with triethyloxonium tetrafluoroborate in CH2C12 gives the 3-ethoxy [cd]benzazulenium tetrafluoroborate (6).

Additional Material: 1 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19820650129

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On the Absolute Configuration of Indane-1-carboxylic Acid (1982)

Brewster, James H.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 317-324

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Doubts that have recently been expressed [1] about the currently accepted (+)-(R), (-)-(S) [2] absolute configuration of indane-1-carboxylic acid appear to be unwarranted. Our ORD. values for 1-methylindane [12] are in error.

Additional Material: 1 Tab.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650134

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Synthese von [16,16,16,16′,16′,16′-2H6] Lycopin (1982)

Hofer, Arnold ; Eugster, Conrad Hans

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 365-370

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Synthesis of [16,16,16,16′,16′,16′ 2H6]LycopeneLycopene having at both ends the deuteriated methyl groups trans to the chain has been synthesized for further biochemical experiments aimed to elucidate the stereochemistry of the cyclization step.Incidentally a gas-chromatographic separation of the isotopisomers 1 and 2g has been observed.

Additional Material: 1 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650138

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Masthead (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982)

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650201

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d5-Reactions of Doubly Deprotonated γ,δ-Unsaturated Carbonyl Derivatives with Electrophiles. A Novel Approach to the Synthesis of Tetrahydrofuran and Tetrahydropyran DerivativesSee also the preceding papers([1] and earlier).For short communications see [2] in [1]. (1982)

Seebach, Dieter ; Pohmakotr, Manat ; Schregenberger, Christian ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 419-450

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The dienone-dianion derivatives 1 react with all types of electrophiles tested (alkyl halide, silyl chloride, ester, ketone, aldehyde, epoxide) to give β, γ-unsaturated carbonyl compounds of type A (see Formulae 2-6, 13, 14 and Tables 1-5). The α- and β-hydroxyalkylation products obtained from 1a-1d can be converted to tetra-hydrofuran and tetrahydropyran derivatives 7 and 16, respectively (Tables 1 and 2), those from the sulfur analogues 1e and 1f to ketene thioacetals 9 and to dienone derivatives 10 and 12. The t-butyl and α-hydroxy-ketones are cleaved to give nitriles, amides, carboxylic acids and esters (Formulae 16-25). The reagents 1 allow to synthesize products with distant functional groups in one step (cf. 1,8-diketones 14 and Formulae 26-30); they correspond to the d5-synthons 31-33; in Table 6, they are compared with other d5-reagents.

Additional Material: 6 Tab.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650202

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Synthesis of Methyl 2-Acetamido-4,6-di-O-acetyl-3-S-acetyl-2-deoxy-3-thio-α-D-mannopyranosidePart VI. of neighboring-group participation in carbohydrate chemistry. For Part V see [1]. (1982)

Miljković, Momčilo ; Hagel, Peter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 477-482

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Methyl-2-acetamido-4,6-di-O-acetyl-3-S-acetyl-2-deoxy-3-thio-α-D-mannopy-ranoside has been synthesized by conversion of methyl 2-amino-2-deoxy-4,6-O-benzylidene-α-D-altropyranoside into the corresponding 3-O-methanesulfony1-2-N-[(methylthio)thiocarbonyl]derivative followed by intramolecular displacement of the 3-O-methanesulfonyloxy group with the (methylthio)thiocarbamoyl group.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650205

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10

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(Perhalogenmethylthio)heterocyclen. XIIXI, Mitt., s.[1]. Herstellung von Perfluoroalkylsulfonylharnstoff-Derivaten sowie CCl3-nFnX-substituierten Heterocyclen und deren biologische Wirkung (1982)

Gerstenberger, Michael R. C. ; Haas, Alois ; Pauling, Horst

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 490-494

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: (Perhalomethylthio)heterocycles XII. Preparation of Perfluoroalkylsulfonylurea Derivatives as well as CCl3-nFnX-Substituted Heterocycles and Their Biological ActivityXI, Mitt., s.[1]In the presence of CF3SO3H (chlorodifluoromethylthio)thiophene 1 reacts with CClF2SCl to give the 2,5-disubstituted thiophene 2a which on oxidation with 30% H2O2-solution yields the corresponding sulfonyl compound 2b · R1SO2NCO adds amines to give R1SO2NHC(O)NHR 3a-g. Some biological properties of these compounds were investigated.

Additional Material: 2 Tab.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650207

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The Stereochemical Outcomes - the Isoborneol/Borneol Ratios - in Lithium, Sodium and Potassium/Ammonia Reductions without a Proton Source of the Enantiomers and the Racemate of Camphor Differ Strongly (1982)

Rautenstrauch, Valentin

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 402-406

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The stereochemical outcomes [ratios (1 R, 2 R, 4 R)-isoborneol/(l R, 2 S, 4 R) isborneol or (1R, 2 S, 4 S)-isoborneol(l S, 2 R, 4 S)-borneol and (1 RS, 2 RS, 4 RS)-isoborneol/(l RS, 2 SR, 4 RS)-borneol] in lithium, sodium and potassium/ammonia reductions without a proton source of the enantiomeric [(1 R, 4 R) or (1 S, 4 S)] and racemic (1RS, 4RS) forms of camphor under the same conditions differ strongly. This explains contradictory reports in the literature and, in the case of the reductions with potassium in which pinacol coupling does not compete, proves that the reductions involve bimolecular reactions between two ketyls, or between the ketone and the ketyl or the ketone dianion.

Additional Material: 2 Tab.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650143

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Mitteilungen - Communication (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 421-424

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650146

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Linear-Reactor-IR.-Matrix and Microwave Spectroscopy of the System O3/NO2/(Z)-2-Butene (1982)

Dommen, Joseph ; Forster, Martin ; Ruprecht, Heidi ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 504-520

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Investigation of the formation of complex reaction products in the gas-phase system O3/NO2/(Z)-2-butene by combination of linear reactors with IR. matrix and microwave Stark Spectroscopy is reported. Besides the polyatomic products observed earlier in the gas-phase ozonolysis of (Z)-2-butene, the following products were identified; N2O5, HNO3, HNO4, CH3NO2, CH3ONO, CH3COONO2 and CH3COO2NO2 (peroxyacetyl nitrate, PAN). Matrix IR. spectra of N2O5, HNO3. CH3COONO, CH3COONO2 required for reference purposes are presented. It is shown that PAN-formation occurs already in the absence of light. A reaction scheme is proposed for explanation of the observed complex NOx-containing products, which assumes methyldioxirane as a central intermediate. Particular reaction steps of the scheme will be discussed, including thermochemical estimates of reaction enthalpies.

Additional Material: 5 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650209

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Lipophilic Diamides as Ionophores for Alkali and Alkaline Earth Metal Cations (1982)

Erne, Daniel ; Ammann, Daniel ; Zhukov, Alex F. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 538-545

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: A series of lipophilic N, N, N′,N′-tetrasubstituted diamides were prepared and their selectivity in solvent polymeric membranes was studied, cis-N, N, N′, N′-Tetraisobutylcyclohexane-1,2-dicarboxamide induces a selectivity in membranes for Li+over alkaline earth metal cations and other alkali metal cations by a factor of about 1000 and 100 respectively. The ionophore N, N′-diheptyl-N,N′-dimethylethylmalonamide is an attractive candidate for the use in microelectrodes for the determination of intracellular Mg2+-activities.

Additional Material: 3 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650211

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Zur Synthese sulfonierter Derivate von 4-Fluoranilin (1982)

Courtin, Alfred

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 546-550

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Syntheses of Sulfonated Derivatives of 4-FluoroanilineSynthesis of 2-amino-5-fluorobenzenesulfonic acid (2) was achieved by baking the hydrogen sulfate of 4-fluoroaniline (1). Sulfonation of p-fluoroacetanilide (4) with oleum followed by hydrolysis gave 5-amino-2-fluorobenzenesulfonic acid (3). The same reaction with 1 yielded 3 in an impure state. The structures of 2 and 3 were confirmed by converting the diazonium chlorides derived from 5-fluoro-2-nitroaniline (5) and from 2-fluofo-5-nitroaniline (8) to 5-fluoro-2-nitrobenzene-sulfonyl chloride (6) and 2-fluoro-5-nitrobenzenesulfonyl chloride (9), respectively, followed by hydrolysis of 6 to 5-fluoro-2-nitrobenzenesulfonic acid (7), and of 9 to 2-fluoro-5-nitrobenzenesulfonic acid (10), and by final reduction. Compound 10 was also obtained by sulfonation of 1-fluoro-4-nitrobenzene (11) with oleum.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650212

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The ESR. Spectrum of the Radical Anion of 1,1,2,2,9,9,10,10-Octafluoro [2.2]paracyclophane (1982)

Gerson, Fabian ; Ohya-Nishiguchi, Hiroaki ; Plattner, Georges

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 551-555

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The radical anion of 1,1,2.2,9,9,10, 10-octafluoro[2.2]paracyclophane (1) has been generated by electrolytic reduction of 1 in 1,2-dimethoxyethane (tetrabutylammonium perchlorate as the supporting salt). The hyperfine coupling constants of the eight 19F-nuclei and the eight protons, af = 3.35 and aH ≈ 0.10 mT, are qualitatively reproduced by INDO. calculations. According to these calculations, the singly occupied orbital of 1⊖ can be represented by an Ag-combination of two ‘symmetric’ benzene LUMO's, with a substantial transfer of spin population into the 2s-AO's of the F-atoms. Line-width alternation in the ESR. spectrum of 1⊖ indicates an ion pairing of the radical anion with its counter-ion Bu4N⊖. The energy barrier to the migration of the cation between two equivalent sites at the radical anion is determined as 14±2 kJ/mol.

Additional Material: 2 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650213

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Variable temperature multinuclear NMR. Investigation of dimethylformamide exchange on the octakis (N,N-dimethylformamide)-thulium(III) ion (1982)

Pisaniello, Dino L. ; Merbach, André E.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 573-581

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The rate of DMF exchange on [Tm (DMF)8]3+ has been determined by 1H- and 13C-NMR. linebroadening techniques. 1H-NMR. yields the following solvent exchange parameters; ΔH* = 33.2 (±0.5) kJ mol-1, ΔS* = 9.9 (±2.4) J K-1 mol-1and k (200 K) = 2.94 (±0.09)× 104 s-1, whilst results from 13C-NMR. are similar. No evidence, by 35C1-NMR., was found of contact ion-pair formation when the perchlorate salts were used.

Additional Material: 3 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650216

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Structures cristallines et moléculaires des muscs macrocycliques. I. La cis-civettone et les variétés polymorphes α et β de sa 2,4-dinitrophénylhydrazone (1982)

Bernardinelli, Gérald ; Gerdil, Raymond

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 558-572

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Crystal and Molecular Structure of Macrocyclic Musks. I. cis-Civetone and polymorphous α- and β-forms of his 2,4-dinitrophenylhydrazonecis-Civetone (C17H30O) forms tetragonal plastic crystals, space groupe 141; a = 9.95(4), c = 32.79(1) Å; Z = 8. The plastic phase exists in a wide temperature range and 731 reflexions could be collected at 153 K. The highly disordered structure model was obtained by the use of direct methods. The molecules appear as ring-shaped diffuse electron-density distributions located in special position.Two polymorphous crystalline forms were isolated for the 2,4-dinitrophenyl-hydrazone of cis-civetone (DNPHCC). Both forms are triclinic, space group P1. Z = 2 (α-Form: a = 6.279(5), b = 12.605(8), c = 15.253(10) Å, α = 105.49(7). β = 100.31 (6), γ = 91.23(7)°; β-Form: a = 7.950(2). b = 8.405 (2). c = 18.233(4) Å, α = 100.28(2), β = 92.29(3), γ = 94.18(2)°). The structures were solved by direct methods and refined to R = 0.11. Each polymorph is associated with a different quinquangular conformation of the macrocycle. In the crystals the intermolecular interactions between macrocycles and aromatic substituents are minimized, the DNPH group being oriented in a face-to-face arrangement across a centre of symmetry.Empirical force field calculations show that the overall intluence of the DNPH moiety on the attached cycle does not significantly modify its conformation with regard to that of the ketone itself.

Additional Material: 8 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650215

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Metal complexes with macrocyclic ligands. XVIPart XV, see [1].. Spectrophotometric and thermodynamic studies of solvents and unidentate ligands interaction with the pentacoordinate Co2+-, Ni2+- and Cu2+-complexes of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (1982)

Micheloni, Mauro ; Paoletti, Piero ; Bürki, Stephan ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 587-594

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The interaction of solvents and of unidentate ligands such as N3-, SCN-, OCN- and OH- with the Co2+-, Ni2+ and Cu2+-complexes of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TMC) have been studied by Spectrophotometric and calorimetric techniques. The spectra in different solvents (Table 2) show that the Ni2+- and probably also the Cu2+-complex with TMC exist as square planar or pentacoordinate species or as a mixture of both, depending on the donor properties of the solvent. The [Co(TMC)]2+-complex is pentacoordinate in all the solvents studied.Ternary complexes [M(TMC)X]n+ are also formed by the unidentate ligands X = N3-, OCN-, OH-, F- and NH3 and their stability constants have been determined. Interesting is the high selectivity of [Ni(TMC)]2+ towards the addition of a further donor (Table 3). Only small ligands such as those listed above form stable adducts, whereas the larger ones such as imidazole or pyridine do not. This is a consequence of the special structure of the complex and of the trans-I-(RSRS)- conformation of the ligand in these complexes. Since the four methyl groups are all on the side of the macrocycle to which the additional unidentate ligand binds, steric interaction between the four methyl groups and the larger ligands prevents the formation of the adducts.The calorimetric measurements show that the stability of the complexes [M(TMC)X]n+ is due to both an enthalpic and entropic contribution which differ in their magnitude (Table 4). This indicates that several antagonistic factors are important in determining the overall stability.

Additional Material: 1 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650218

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Mitteilungen - Communication (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 620-622

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19820650223

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Structures of Ganoderic Acid A and B, Two New Lanostane Type Bitter Triterpenes from Ganoderma lucidum (FR.) KARST.Dedicated to Prof. Dr. Conrad Hans Eugster on the occasion of his 60th birthdayKey words: Ganoderma lucidum (Fr.) KARST. Ganoderic acid A and B, Bitter triterpene, 7β, 15α-Dihydroxy-3, 11, 23-trioxo-5α-lanost-8-en-26-oic acid. 3β, 7β-Dihydroxy-11, 15, 23-trioxo-5α-lanost-8-en-26-oic acid (1982)

Kubota, Takashi ; Asaka, Yukihiro ; Miura, Iwao ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 611-619

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The structures of two new bitter triterpenes, ganoderic acid A and B. isolated from a mushroom Ganoderma lucidum (FR.) Karst. (Polyporaceae) were determined as 1 and 2 on the basis of spectral data. Ganoderic acid A is a novel highly oxidized triterpene bearing a boat-shaped A-ring of lanostane.

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Structures cristallines et moléculaires des muses macrocycliquesPartie I: [1]. II. La trans-civettone et sa 2,4-dinitrophénylhydrazone (1982)

Bernardinelli, Gerald ; Gerdil, Raymond

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 730-738

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Crystal and Molecular Structure of Macrocyclic MUSKS. II. trans-Civetone and its 2, 4-DinitrophenylhydrazoneThe trans and cis isomers of civetone (C17H30O) crystallize in isomorphous systems and form plastic crystals (tetragonal, space group I41 a=9.95 (4), c = 32.79 (1) Å, Z = 8). Mixed crystals were prepared with cis-civetone as second component. Accordingly the diffuse structural model obtained for the disordered phase of the cis-isomer [1] is also regarded as representative of that of trans-civetone.The crystal structure of trans-civetone 2,4-dinitrophenylhydrazone (DNPHTC; C23H34N4, Monoclinic, Space group P21/c, a=8.364(2), b=7.971(1), c=36.025(8) Å, β=91.44 (2)°) was solved by direct methods and refined to a final R of 0.09 (Rw = 0.021). The macrocycle adopts a sexangular conformation [23*434*44*], and its mean plane is approximatively perpendicular to that of the aromatic substituent. Empirical force field calculations have shown that the DNPH substituent has very little influence on the macrocycle conformation. The intermolecular interactions take place essentially between groups of the same type: macrocycle…macrocycle and DNPH…DNPH.

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Synthesis and Photo-oxygenation of Some Substituted 1-Benzyl-3,4-dihydroisoquinolines. Mechanism of Enamine Photo-oxygenation (1982)

Martin, Ned H. ; Jefford, Charles W.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 762-774

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The synthesis of a series of substituted 1-benzyl-3,4-dihydroisoquinolines by Bischler-Napieralski cyclization is described. Competitive methylene blue sensitized photo-oxygenation experiments allowed the determination of relative rates of photo-oxygenation of 1-benzyl-3,4-dihydroisoquinolines, Substituents were shown to affect both the equilibrium concentration of the tautomeric enamine and the overall photo-oxygenation rate. After correcting for differences in enamine concentration, the relative rate data provided a diagnostic probe of the reaction mechanism, which involves transfer of charge in the rate-limiting step.

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URL: http://dx.doi.org/10.1002/hlca.19820650314

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Spectrophotometric and Nuclear Magnetic Resonance Study of Temperature- and Pressure-induced Changes in the Intimate Solvation of Neodymium (III) in N, N-Dimethylformamide and Trimethylphosphate (1982)

Pisaniello, Dino L. ; Nichols, Peter J. ; Ducommun, Yves ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1025-1028

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The temperature- and pressure-dependent equilibria for the addition of an extra N, N-dimethylforrnamide (DMF) or trimethylphosphate (TMP) ligand onto [Nd (DMF)8]3+- and [Nd(TMP)6]3+-species respectively have been measured by visible spectrophotometry. Complementary NMR. studies on other lanthanide ions show a gradual shift in preference for the lower coordination number across the lanthanide series.

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Face Selectivity of the Diels-Alder Additions of Exocyclic Dienes Grafted onto 7-Oxabicyclo[2.2.1]heptanesInteraction between non-conjugated chromphores, Part 16; Part 15, see [1]. An exocyclic butadiene moiety means that each double bond is in an exocyclic position on the ring skeletonFor a preliminary report, see [2] (1982)

Mahaim, Cyril ; Vogel, Pierre

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 866-886

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Keywords: Chemistry ; Organic Chemistry

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Notes: Stereoselective syntheses of 2exo, 3exo-bis (chloromethyl)-5-[(Z)-chloromethylidene]- (9), 2exo, 3exo-bis (chloromethyl)5-[(E)-chloromethylidene]- (10) and 2exo, 3exo-bis(chloromethyl)-5-[(E)-methoxymethylidene]-6-niethylidene-7-oxa-bicyclo[2.2.1]heptane (13) are presented. Double elimination of HCI from 9, 10 and 13 yielded 2-[(Z)-chloromethylidene]- (14), 2-[(E)chloromethylidene]- (15) and 2-[(E)-methoxymethylidene]-3,5,6-mmethylidene-7-oxabicycio[2.2.1]heptane (18), respectively, without loss of the olefin configuration. Ethylene tetracarbonitrile (TCE) and N-phenyltriazolinedione (NPTAD) added to these new exocyclic dienes and tetraenes preferentially onto their exo-face. The same face selectivity was observed for the cycloadditions of TCE to the (Z)- and (E)-chlorodienes 9 and 10, thus realizing a case where the kinetic stereoselectivity of the additions is proven not to be governed by the stability of the adducts. The exo-face selectivity of the Diels-Alder additions of dienes grafted onto 7-oxabicyclo [2,2.1]heptanes contrasts with the endo-face selectivity reported for a large number of cycloadditions of dienes grafted onto bicyclo[2.2.1]heptane skeletons.

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URL: http://dx.doi.org/10.1002/hlca.19820650321

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Effects of Remote Substitution on the Photo-oxidation of Exocyclic s-cis-Butadienes Grafted onto Bicyclo [2.2.1]heptanes. Thermal and Rhodium Catalyzed Rearrangements of 3,6-Dihydro-1,2-dioxinesInteraction between non-conjugated chromophores, Part. 17. Part 16, see [1]. An exocyclic butadience moiety means that each double bond is in an exocyclic position on the ring skeleton.This work has been presented at the 8th IUPAC Symposium on Photochemistry, in Seefeld, Austria, July 13-19, 1980. (1982)

Hagenbuch, Jean-Pierre ; Birbaum, Jean-Luc ; Métral, Jean-Luc ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 887-895

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The rates of photo-oxidation of exocyclic S-cis-butadienes grafted onto bicyclo-[2.2.1]heptanes and 7-oxabicyclo[2.2.1]heptanes (1-6) are dependent upon remote modifications of the bicyclic skeletons. They correlate with the rates of Diels-Alder additions of these dienes to strong dienophiles. The 2,3-dimethylidenenorbornane (1), 5,6-dimethylidene-2-norbornene (2) and 2,3-dimethylidene-7-oxanorbornane (3) gave the corresponding endo-peroxides (3,6-dihydro-1,2-dioxines) 7-9 in good yield. The 2, 3, 5, 6-tetramethylidene-7-oxanorbornane (4) gave the mono-endo-pe-roxide 6, the latter did not react with a second equivalent of oxygen. Similarly, 5, 6-dimethylidene-7-oxa-2-norbornene (5) was unreactive toward photo-oxidation. Thermal isomerization of the endo-peroxides 7 and 9 gave, the trans-diepoxides 10 and 14, respectively, with high stereoselectivity. The endo-peroxides 6, 7 and 9 were cleanly isomerized into the corresponding α, β-unsaturated γ-hydroxy aldehydes in the presence of catalytic amounts of Rh2(CO)4Cl2.

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Synthese und Circulardichroismus optisch aktiver Carotinoidmodelle (1982)

Buchecker, Richard ; Marti, Urs ; Eugster, Conrad Hans

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 896-912

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Keywords: Chemistry ; Organic Chemistry

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Notes: Synthesis and Circular Dichroism of Optically Active Carotenoid ModelsThe synthesis of the following optically active carotenoidic model compounds are described: ( - )-(3,S,3′S)-3,3′-diisopropenyl-16,17,18,16′,17,18′-hexanor-β,β-carotene (1), (3R,3′R)-19,20,19′,20′-Metranor-zeaxanthin (2) and (6R,6′R)-19,20, 19′,20′-tetranor-ε,ε-carotene (3). These compounds were synthesized for the following reasons: (1) the presence of methyl groups at C(1), C(1′), C(5), C(5′) of cyclic carotenoids profoundly affects the torsional angle of the C(6), C(7)- and C(6′), C(7′)-bonds. Sign and magnitude of this angle are, according to recent theories [4] [5], responsible for a helical chromophore and for strong conservative [4] Cotton effects. CD. measurements of 1 give experimental support to these state- 1 exhibits weaker and less temperature dependent Cotton effects. Of more significance, the shape of the curve is no longer conservative, as expected. This constitutes experimental evidence for the contention that the β-endgroups and the polyene chain indeed form an inherently dissymmetric chromophore in optically active β, β-carotene derivatives; (2) the slightly S-shaped form of the polyene chain of carotenoids, shown by X-ray analyses [12] [13], is mainly ascribed to the presence of the methyl groups in the chain. Models 2 and 3 therefore are assumed to be linear. CD. studies of these compounds should consequently give information about the influence of deviation from Linearity and planarity of the polyene on the CD. spectra of carotenoids. CD measurements of 2 and 3 show that the lack of methyl groups does not alter the general type of the curve. Only the intensity and to some extent the position of the Cotton effects are influenced. Carotenoids with the ε-endgroup possess inherently symmetric but asymmetrically distorted chromophores.The assumption that non-conservative CD. spectra could become conservative upon cooling [4] is experimentally confirmed by model 3.The rule stating that pairs of all-(E) and mono-(Z) isomers of carotenoids with only one cyclic endgroup should have CD. spectra with the same sign [5] is disproved by the CD. spectra of four stereoisomeric rubixanthins (s. Fig. 5).The UV./VIS. spectrum of 3, λmax 447 (ε 216000), 418 (ε 189000) exhibits the highest molecular extinction ever reported for a carotenoid.

Additional Material: 5 Ill.

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Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6-Oxo-isophoron. VI. Synthese Von Rhodoxanthin und (3-RS, 3′RS)-Zeaxanthin; Zugänge zur C15-Ringkomponente über 3-Oxo-jonon-DerivateV. Mitteilung dieser Reihe:[1]Herrn Professor Dr. Walter Boguth zum 65-Geburtstag gewidmet (1982)

Widmer, Erich ; Soukup, Milan ; Zell, Reinhard ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 944-957

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Keywords: Chemistry ; Organic Chemistry

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Notes: Technical Procedures for the Synthesis of Carotenoids and Related Compounds from 6-Oxo-isophorone, VI. Synthesis of Rhodoxanthin and (3RS, 3′RS)-Zeaxanthin; Routes to the C15-Ring Component via 3-Oxo-ionone DerivativesThe C15-ring component 4, key intermediate of a new scheme for the synthesis of rhodoxanthin (1) and (3RS, 3RS)-zeaxanthin (3), has been synthesized starting from 6-oxo-isophorone (7) via 3-oxo-cyclocitral and 3-oxo-ionone derivatives.

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URL: http://dx.doi.org/10.1002/hlca.19820650327

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Structures cristallines et moléculaires des muscs macrocycliquesPartie II:[1] III. La muscone et sa 2,4-dinitrophénylhydrazone (1982)

Bernardinelli, Gérald ; Gerdil, Raymond

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1310-1317

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: Crystal and Molecular Structure of Macrocyclic Musks. III. Muscone and its 2, 4-DiuitrophenylhydrazoneMuscone (3-methylcyclopentadecanone C16H30O) forms orthorhombic plastic-crystals with Z = 2 (a = 5.560(4), b = 8.176(6), c = 17,168(20) Å). Single crystals are obtained by zone melting at 258 °K. The high degree of disorder and the ambiguity of space group have precluded a structural determination by X-ray diffraction methods.The crystal structure of muscone 2,4-dinitrophenylhydrazone (DNPHM; C22H34N4O4, triclinic, space group P¯, a = 8.015 (4), b = 8.235 (2), c = 17.409 (4) Å. α = 102.69 (4), β; = 93.86 (3), γ = 96.03 (3)° Z = 2) was solved by direct methods and refined to a final R of 0.155 (Rω = 0.102). The macrocycle shows static disorder, which could be partially resolved by analysis of the anisotropy of the atomic vibrational parameters. Eight possible conformers with reasonable geometries emerged from the subsequent refinements and were used as starting models in force-field calculations, which converged to four quinquangular conformations ([25233]; [34233]; [21423*4]; [3423*4]) with similar energies. In the molecular packing, the interactions between macrocycles and substituents are minimized. They are comparable to those described for the cis- and trans-civetone DNPH derivatives [1] [2].

Additional Material: 6 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19820650422

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Masthead (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982)

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

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URL: http://dx.doi.org/10.1002/hlca.19820650501

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The Synthesis of 4-Decarboxy-4-phosphono-O-2-isooxacephems, -isopenams and -isooxacephems Containing Phosphorus at the 3-Position (1982)

Hakimelahi, Gholam Hosein ; Just, George

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1359-1367

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Notes: Two new types of iso-oxacephems have been synthesized in which a phosphonate group replaces either the carboxyl group or C(3). The latter compound exists as a stable trialkoxyphosphonium ylide.Potassium thioacetate and O2 in DMF are transformed in an autocatalytic, probably sulfur-catalyzed process to CH3COOK and sulfur; the latter two reagents are sufficient to transform the methanesulfonate 7 to the isopenam 15.

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132. The Synthesis of Highly Strained Monocyclic and Bicyclic β-Lactams (Δ1-Carbapenem) (1982)

Hakimelahi, Gholam Hosein

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1378-1384

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Notes: The synthesis of some β-lactams and one Δ1-carbapenem is described. The electronic activation of monocyclic β-lactams of type 1 is not sufficient to generate a bioactive compound.

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Persistance of the Cyclopnane Radical Anions and its Relation to Structure (1982)

Gerson, Fabian ; Lopez, Javier ; Boekelheide, Virgil ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1391-1397

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Notes: Reactions of [2N]cyclophanes (N = 2,⃛6) with solvated electrons in 1,2-di-methoxyethane at 193 K have been studied by ESR. and ENDOR. spectroscopy. All but the two most highly bridged cyclophanes (N = 5 and 6) are reduced to paramagnetic species under these conditions. Whereas the radical anions of [2.2]-paracyclophane and [23](1,2,4)- and [24](l,2,4,5)cyclophanes are sufficiently persistent to be characterized by their hyperfine data, those of the remaining five cyclophanes undergo a rapid cyclization to the radical anions of 4,5,9,10-tetrahydropyrenes. These have been identified as the unsubstituted tetrahydropyrene (from [2.2]-metacyclophane and [23](l,2,3)cyclophane), the 2,7-dimethyl-derivative (from [23](1,3,5)- and [24](l,2,3,5)cyclophanes) and the 1,8-dimethyl-derivative (from (24l,2,3,4)cyclophane). The persistence of the cyclophane radical anions seems to depend on the numbers, nmeta and npara, of the meta-and para-positions of the bridging ethano groups in the two benzene rings. The prerequisite for the radical anion to be persistent is nmeta≤npara.

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Stoffwechselprodukte von Mikroorganismen 215. Mitteilung214. Mitt., s. [1] Röntgenstrukturanalyse von Di-O-acetyl-aspochalasin C (1982)

Neupert-Laves, Katartna ; Dobler, Max

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1426-1431

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Notes: The X-ray crystal structure analysis of the 17,18-di-O-acetyl derivative of the antibiotic aspochalasin C (monoclinic, a = 26.377, b = 10.840, c = 11.937 Å, β = 102.08°, space group C 2) confirms the constitution elucidated by spectroscopic methods and chemical degradation, and establishes the relative configuration.

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Kutney, James P. ; Dimitriadis, Eugene

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1351-1358

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Notes: An improved synthesis of the isomeric 12- and 14-chlorodehydroabietic acids (3 and 2, respectively) and 12,14-dichlorodehydroabietic acid (4) is described. The monochioro isomers were conveniently separated as the imidazole derivatives, and conversion of the latter to the free acids or their corresponding methyl esters could be achieved in high yield. Studies involving microbial degradation of 2-4 are underway.

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Kutney, James P. ; Dimitriadis, Eugene ; Hewitt, Gary M. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1343-1350

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Notes: One of the fish-toxic chlorinated resin acids, 14-chlorodehydroabietic acid (5), found in kraft mill effluent is examined. When exposed to the fungus Mortierella isabellina, 5 is converted into a number of hydroxylated derivatives which show low levels of toxicity to fish. These biotransformation products were isolated and characterized.

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Synthesen und chemische Eigenschaften neuer «Donor-Akzeptor»-stabilisierter Molekülsysteme mit zentraler Bicyclo [4.4.1]undeca-l (10), 3,6,8-tetraen-2,5-diyliden-GruppeMeinem lieben Freund und Kollegen, Herrn Professor Dr. Werner Heimann, Karlsruhe, mit herzlichen Wünschen zum 70. Geburtstag gewidmet (1982)

Neidlein, Richard ; Zeiner, Hartmut

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1333-1342

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Notes: Syntheses and Chemical Properties of New ‘Donor-Acceptor’-stahilized Molecular Systems with a Central Bicyclo[4.4.1] undeca-l(10).3,6,8-tetraene-2,5-diylidenc GroupThe synthesis of X-methyl-2-(5-oxobicyclo[4.4.1]undeca-l)10(,3,6,8-tetraen-2-yliden)-l,3-benzodithiol (4) is described starting with the keto-enol mixture 2 and 5-methyl-1,3-benzodithiolium perchlorate. Under rearomatization of the central frame protonation of 4 yields the salt 4c. The reaction of 4 with dicyanoketene gives the ‘push-pull-substituted’ 5, and with 9-carbonylfluorene the fulvalene derivative 7, which can be protonated by CF3CO2H at C(9″) to the salt 8. The reaction of 2-methylthio-l,3-dithiolium jodide 9 with the keto-enol mixture 2 yields 10, which, on protonation at the carbonyl group by CF3CO2H, gives the salt 11 under rearomatization. The spectral data of the new compounds 4, 4c, 5, 7, 8, 10 and 11 are reported and discussed.

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The Synthesis of an O-2-Isooxacephem (1982)

Hakimelahi, Gholam Hosien ; Just, George ; Ugolini, Antonio

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1368-1373

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Notes: The synthesis of an iso-oxacephem is described. Reaction of methanesulfonyl chloride with hydroxyaldylmalonates can form sulfones or sulfonates, their ratio varying with the basicity of the tertiary amine used in the sulfonation.

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URL: http://dx.doi.org/10.1002/hlca.19820650506

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The Synthesis of Dibenzyl trans-{7-oxo-3-phenyl-6-phenylacetamido-1-azabicyclo [3.2.0]heptane}-2,2-dicarboxylate (Carbapenam) (1982)

Hakimelahi, Gholam Hosein ; Ugolini, Antonio ; Just, George

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1374-1377

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The synthesis of the title compound is described.

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High-Pressure 17O-NMR. Study of Vanadium (II) in Water: A Second Example of an Associative Interchange Mechanism (Ia) for Solvent Exchange on an Octahedral Divalent Transition-Metal IonPart 15 of the series: High-Pressure NMR. Kinetics. For Part 14 see [1]Presented in part at the 8th AIRAPT Conference, Uppsala, Sweden, August 17-22, 1981. (1982)

Ducommun, Yves ; Zbinden, Donald ; Murbach, André E.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1385-1390

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Notes: The water exchange of [V(H2O)6]Cl2 in aqueous solution has been studied as a function of temperature and pressure (up to 250 MPa), by measuring the 17O-FT-NMR. line-widths of the free water resonance at 8.13 MHz. The kinetic parameters obtained are K298m = 87±4 s-1, ΔH* = +61.8 ± 0.7 kJ mo1-1 and ΔS* = -0.4±1.9 J mol-1 K-1. A pressure-independent volume of activation ΔV* = -4.1±0.1 cm3 mol-1 is obtained, suggesting an associative interchange (Ia) mechanism for this early divalent metal ion.

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Total Synthesis of (±)-3-Deoxy-7,8-dihydromorphine, (±)-4-Methoxy-N-methylmorphinan-6-one and 2,4-Dioxygenated (±)-CongenersThe morphinanones reported in this paper are racemic entities. Only (±)-2 and (±)-3 obtained by total synthesis shall be recorded with prifix, in order to differentiate them from their (±)-enantiomers 2 and 3 prepared from natural morphine(1) (1982)

Hsu, Fu-Lian ; Rice, Kenner C. ; Brossi, Arnold

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1576-1589

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: A total synthesis of racemic 3-deoxy-7,8-dihydromorphine ((±)-2) and 4-me-thoxy-ALmethylmorphinan-6-one ((±)-3) is described. The key intermediate was 2,4-dihydroxy-N-formylmorphinan-6-one (11), obtained from 3,5-dibenzyloxy-phenylacetic acid (4) in 41.8% overall yield. Bromination of 11, and treatment with aqueous NaOH-solution afforded, after N-deblocking and reductive N-methylation with concomitant removal of the aromatic bounded Br-atom, the morphinanone 14. Elimination of the HO-C(2) group in 14 was accomplished by hydrogenolysis of its N-phenyltetrazolyl ether 15, to give 3-deoxy-6,0-didehydro-7,8-dihydromorphine (16). Reduction of 16 with L-Selectride at low temperature provided (±)-2 in high yield. The ether 15 directly afforded, under more vigorous reduction conditions, 4-hydroxy-N-methylmorphinan-6-one (17). and after O-methylation of 17, the methyl ether (±)-3 was obtained. A (1:l)-mixture of 4-hydroxy-2-methoxy-N-methylmor-phinan-6-one (28) and its 2-hydroxy-4-methoxy isomer 30 svere obtained by Grewe-cyclization of a mono-methoxylated aromatic precursor similar to that which afforded 11. The 2,4-dioxygenated N-methylmorphinan-6-ones 29, 31 and 38 were also prepared and characterized.

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Kreuzkonjugierte Cyanine und Merocyanine aus Salzen 1-substituierter 2,3-Dimethylchinoxaline. 2. Mitteilung Über die oxydative Umwandlung der Farbbasen (1982)

Schelz, Dieter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1607-1616

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Keywords: Chemistry ; Organic Chemistry

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Notes: Crossconjugated Cyanines and Meroeyanines, Obtained from Salts of 1-Substituted 2,3-Dimethylquinoxslines. 2nd Communication. On the Syntheses of Dehydro-FormsProducts 3 of the readily oxidized 1 and 2 are found to be sensitive to solvolysis, especially when X and R are electron-withdrawing substituents. In some cases, the salts 3 could be identified as the oxidation products of the salts 9. The oxidation of 9p (X = 5,6-benzo, R=CH3) by an alkaline solution of K3Fe(CN)6 leading to the quinoxalinone 10p is compared with the voltammetric oxidation of 81 (X = H, R=4-C1C6H4) and related to Viehe's [15] c, d-stabilized radicals. 1H-NMR.-spectra of the salts 3 are discussed with regard to the (E/Z)-isomers,

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Erratum (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1685-1685

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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URL: http://dx.doi.org/10.1002/hlca.19820650540

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Iridoide aus Verbascum nigrum L. 182. Mitteilung über organische Naturstoffe (1982)

Seifert, Karlheinz ; Schöpp, Emanuel ; Hesse, Manfred ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1678-1684

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Notes: Iridoids from Verbascum nigrum L.Two new iridoid glycosides, nigroside 1 ( = 6-O-(3-O-einnamoyl-α-L-rhamno-pyranosyl)aucubin (2), and nigroside 2 (=6-O-(2-O-cinnamoyl-α-L-rhamnopy-ranosyl)aucubin (3), and the known compound laterioside (1) have been isolated from extracts of the stems of Verbascum nigrum L., and their structures established primarily on the basis of NMR. spectroscopy. Harpagoside (4), a known iridoid glucoside, was also isolated from the roots of this plant.

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Mitteilungen - Communication (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1686-1689

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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Structural analogues of aporphines. Part II: Synthesis of some isomers of lysergic acid derivatives (1982)

Berney, Daniel

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1694-1699

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: Isomers of lysergic acid derivatives (3, 22, 23 and 24). analogous to aporphine, have been synthesized from the key intermediate ketone 12.

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Regioselective Synthesis of 2-oxo-2,8-dihydro-[l,2,4] oxadiazolo [2,3-a]pyrimidine-7-carbamates: A New Class of Antihypertensive Peripheral Vasodilators (1982)

Muller, Jean-Claude ; Ramuz, Henri

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1445-1453

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Notes: The synthesis of new 2-oxo-2,8-dihydro-[l,2,4]-oxadiazoo-[2,3-a] pyrimidine-carbamates 3 described in this paper is based upon a regioselective heterocyclization of the pyrimidine-2,6-bis (alkoxycarbonylamino) N-oxides 4. Structural and mechanistic aspects of that cyclizalion are discussed.

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Polar Effects. X. Polar Substituent Effects in the Solvolysis of 3-Substituted 1-Adamantyl Bromides and Toluenesulfonates (1982)

Grob, Cyril A. ; Schaub, Bruno

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1720-1727

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The rate constants for 3-substituted adamantyl p-toluenesulfonates 3a-3k in ethanol/water 80:20 correlate well with the respective inductive substituent constants σIq. The reaction constant ρ for the toluenesulfonates 3 is 10% larger than for the corresponding bromides 2, indicating somewhat more charge separation in the activation of the toluenesulfonates. Evidence is presented that stabilization of the resultant 1-adamantyl cations by induction involves graded 1,3-bridging, which is favored when the substituent is an electrofugal group, and that stabilization by n-electron donors involves C, C-hyperconjugation. Rate ratios for the toluenesulfonates 3 and the bromides 1 exceed 103 and are almost independent of the 3-substituents. The implications of this are discussed in the light of current hypotheses.

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Optically Active t-Butyl 2-(p-Tolylsulfinyl)propionate and -butyrate: Synthesis and Reactivity in Aldol-type Condensations (1982)

Solladié, Guy ; Matloubi-Moghadam, Firouz ; Luttmann, Claude ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1602-1606

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The syntheses of optically active t-butyl 2-(p-tolylsulfinyl)propionate and -butyrate (2a and 2b, respectively) are described, and it is shown that aldol-type condensation of the corresponding enolates is limited by steric hindrance. Optically active (2a) reacted, however, in high yield with aliphatic aldehydes and lead to 80% of asymmetric induction.

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Synthese von 5,6-Epimino-5,6-dihydro-β-jonon (1982)

Müller, Ernst Peter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1617-1626

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: Synthesis of 5,6-Ephnino-5,6-dihydro-β-iononeIn order to synthesize the title compound 5 the 2-azidoalcohols 3 and 4 were treated with various nucleophilic phosphorus compounds. It was found that the course of the reaction depends strongly upon the kind of nucleophilic phosphorus derivative used.

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Synthése totale d'α-disaccharidyles de tridésoxy-2,5,6-streptamine apparentés aux aminosides à partir du maltose et du lactose (1982)

Rolland, Nicole ; Vass, Georges ; Cleophax, Jeanine ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1627-1636

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Notes: Total synthesis of α-disaccharidyl-2,5,6-trideoxy-streptamines related to aminoglycoside antibiotics derived from maltose and lactoseThe synthesis of the hitherto unknown 4-O-substituted α-linked pseudo-tri-saccharides 1,2 and 3 is described. The key intermediates required in the reaction sequence are the glycals 12, 13 and 14, prepared from maltose, lactose and the chiral ditosyloxy-cyclohexanol 15, readily accessible from quinic acid. The pivotal step in the reaction's scheme - a stereospecific α-glycosylution procedure -, is an acid-catalyzed addition of the alcohol 15 to the glycals 12, 13 and 14 leading to the corresponding 2,3-unsaturated trisaccharides. The latter compounds were transformed to the target α-glycosides of 2,5,6-trideoxystreptamine 1, 2 and 3 which were devoid of significant antibacterial activity. These results indicate that the presence of an ether linkage at the position 4′ is probably critical for antibacterial activity.

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Asymmetrische Micheal-Additionen.Vgl. Unsere frühere Arbeit [1] über diastereoselektive Micheal-Additionen von Enamenen aus offenkettigen Ketonene und Morpholin an Nitroolefine Praktisch vollständigdiastereo- und enantioselektive Alkylierungen des Enamins aus Cyclohexanon und Prolinylmethyläther.Umdie Beziehung zum Prolin hervorzuheben, bezeichnen wir diese Verbindung als Prolinylmethyläther-Derivat, statt den systematischen Namen N(1′-Cyclohexenyl)-2-methoxymethyl-phyrrolidin zu benutzendurch ω-Nitrostyrole zu u-2-(l′-Aryl-2′-nitroäthyl)cyclohexanonen Übersicht über die like/unlike-Spezierung der relativen Topizität und der relativen Konfiguration siehe [2] (1982)

Blarer, Stefan J. ; Schweizer, W. Bernd ; Seebach, Dieter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1637-1654

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Notes: Asymmetric Michael-Additions Practically Completely Diastereo- and Enantloselective Alkylations of the Enamine from Cyclohexanone and Prolinyl Methyl Ether by ω-Nitrostyrenes to Give u2-(1′-Aryl-2′-nitroethyl)cyclohexanonesWhen the enamine (S)-N-(1′cyclohexenyl)-2-methoxymethyl-pyrrolidine is added to 2-aryl-l-nitroethylenes, only one of the four possible enantiomerically pure diastereomers is formed. Hydrolysis of the crude primary products furnishes α-alkylated cyclohexanones of 〉 90% e. e. (3, Scheme 3). Their (2S,1′R)-configuration was deduced by chemical correlation with l-cyclohexyl-l-phenyl-ethane and from an X-ray crystal structure analysis of (-)-(2R,3S,6′R1,l″S′)-3-methyl-N-[6′-(2″-nitro-l″-phenylethyl)-l′-cyclohexenyl]-2-phenylmorpholine (lla, Scheme 5 and Fig. 2). - The relative topicity of reactant approach with the prolinol derivative (see II) is specified as lkul-l,4. The steric course and the mechanism of the reaction are discussed.

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Polarographic Properties and Electrochemical Reduction of 1,2-Dimethyl-3-indolyl Heteroaryl Ketones (1982)

Naef, Rudolf

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1734-1742

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The reduction of a series of 1,2-dimethyl-3-indolyl heteroaryl ketones, where the heteroaryl components are 2-benzoxazolyl, 2-behzpthiuzolyl. 1-methyl-2-benz-imidazolyl, 4- and 2-pyridyl, in aprotic and prone solution are described by means of DC. and AC. polarography, cyclic voltammetry and coulometry.In acetonitrile a two-step reduction mechanism with a reversible first and an irreversible second one-electron transfer has been observed, confirmed by AC.-polarographic and cyclovoltammetric measurements. The reduction potentials, between -1.377 and -1.787 V for the first step, and between -1.937 and -2.250 V (vs. Ag/AgCl) for the second, could not be correlated with the LUMO energies from HMO calculations which was explained as being due to a distorted configuration of the π systems.In protic media (ethanol/water) reduction occurs in an irreversible one-step mechanism. Measurements of the pH dependence of the half-wave potential in the pH* range 0-12 and the evaluated transfer coefficients show that the reduction step represents the transfer of two electrons and two protons yielding secondary alcohols and no dimerization products under any condition. These findings are supported by coulometric and macroscale electrolysis of the ketones; the products isolated were characterized by IR. and 1H-NMR. data.

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Rapid Silylation of a Glass Surface: Choice of Reagent and Effect of Experimental Parameters on Hydrophobicity (1982)

Deyhimi, Farzad ; Coles, Jonathan A.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1752-1759

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The silylation of the surface of sodium borosilicate glass was investigated under conditions that might be applied to the fabrication of ion-selective microelectrodes of the liquid membrane type such as are used in physiology, Silylation was carried out for 15 min at different temperatures and with six different silanes. The hydrophobicity was measured and found to be greatest with reaction temperatures of 200-350°, the effectiveness of the different silylating agents being in the (increasing) order: trimethylchlorosilane, tributylchlorosilane, (dimethylamino)trimethylsilane, hexamethyldisilazane, dimethyldichlorosilane, bis(dimethylamino)dimethylsilane. The results give evidence of a catalytic effect of basic amine groups and show that the reactivity of the surface of freshly drawn glass is increased by acid leaching.

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1-p-Menthene-8-thiolPatent applications relative to the use of 1-p-menthene-8-thiol (B) have been filed in several counties by Firmenich SA, Geneva(Priority: 23.12.1980).: A powerful flavor impact constituent of grapefruit juice (Citrus parodisi MACFAYDEN) (1982)

Demole, Edouard ; Enggist, Paul ; Ohloff, Günther

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1785-1794

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: 1-p-Menthene-8-thiol (B) is shown to be a potent character-donating constituent of grapefruit juice, in which it occurs at the ppb-level or below. A convenient synthesis is described for this terpene-thiol, apparently the most powerful flavor compound ever found in nature.

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17O-NMR. of Enriched Acetic Acid, Glycine, Glutamic Acid and Aspartic Acid in Aqueous Solution. I. Chemical Shift StudiesPreseted in part at the 6th Meeting of the ‘Groupe d'Etude en Résonance Magnétique (GERM)’, Pont-à-Mousson, France, March 1982. (1982)

Gerothanassis, Ioannis P. ; Hunston, Roger ; Lauterwein, Jürgen

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1764-1773

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The 17O-NMR. chemical shifts of the enriched amino acids glycine, aspartic acid and glutamic acid were measured in aqueous solution as a function of pH. High magnetic fields are necessary to resolve the α, β- and α, γ-carboxyl resonances of aspartic acid and glutamic acid, respectively. The chemical shifts of acetic acid were measured for comparative reasons. Ionization constants and titration shifts were obtained by nonlinear least-squares fits to one-proton titration curves. The average excitation energy approximation is discussed in terms of the observed changes in 17O-shielding on deprotonation. No intramolecular association between the α-amino group and the α-carboxyl group in the zwitterionic form is required to explain the high-frequency shift of the carboxylate ion. Also no indication of an intramolecular association between the α-amino group and the side-chain carboxyl groups of aspartic acid or glutamic acid was found.

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Preparation and Conformational Properties of Benzylpenicilloyl-oligo-L-lysine Conjugates (1982)

Rolli, Hanspeter ; Lüscher, Immanuel F. ; Schneider, Conrad H. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 1965-1971

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Keywords: Chemistry ; Organic Chemistry

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Notes: Selected oligo-L-lysine carriers and a poly-L-lysine were penicilloylated with benzylpenicillin. The resulting conjugates 2-6 were studied by IR. absorption in the solid state and circular dichroism measurements in solution. The IR. data demonstrate the lack of β-structure formation even in medium-sized peptides where such structures might be expected on the basis of previous studies on differently substituted oligo-L-lysines. Considerable proportions of right-handed α -helical conformation are exhibited by the icosa-L-lysine and poly-L-lysine conjugates 5 and 6 in water and 2,2,2-trifluoroethanol. Difficulties in obtaining fully penicilloylated conjugates are not related to the extent of α-helical conformation in aqueous solution.

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17O-RMN. d'éthers, de cétones et d'esters cycliques. Détermination de constante de couplage quadrupolaire (1982)

Delseth, Claude ; Kintzingcr, Jean-Pierre

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2273-2279

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Keywords: Chemistry ; Organic Chemistry

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Notes: 13C- and 17O-relaxation times measured in cyclic ethers, cyclic ketones, and lactones allowed the determination of the quadrupolar interaction at the O-site. Values obtained for six-membered rings can be used as standard values for ethers (χ = 13 MHz), ketones (χ = 10.5 MHz), and esters (χ = 11.5 MHz for dicoordinated and 9.5 MHz for monocoordinated O-atom). Even within a series, no correlation is found between the 17O-chemical shift and the value of quadrupolar interaction.

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Synthese makrocyclischer Lactame aus Ketonen durch Ringerweiterung. Vorläufige MitteilungEine ausführliche Mitteilung ist in Vorbereitung. (1982)

Wälchli, Rudolf ; Hesse, Manfred

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2299-2301

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Synthesis of Macrocyclic Lactams from Ketones by Ring Enlargement Reaction2-Nitroalkanon 1 was converted to the N-substituted amide 3 by condensation with acrylaldehyde followed by reductive amination. Under the analogous reaction conditions, 2-nitrocyclododecanon (4) led to 12-nitro-15-pentadecanlactam (6).

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Reaktion von 3-Dimethylamino-2,2-dimethyl-2H-azirin mit 6-Methyluracil; Kristallstruktur der Reaktionsprodukte (1982)

Dähler, Marlise ; Prewo, Roland ; Bieri, Jost H. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2302-2312

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: Reaction of 3-Dimethylamino-2,2-dimethyl-2H-azirine with 6-Methyluracil; Crystal Structure of the ProductsThe reaction of 3-dimethylamino-2,2-dimethyl-2H-azirine (1) with 6-methyl-uracil (4) in 2-propanol at 80° yields the 4H-imidazoje derivative 5 as the main product. This reaction is similar to the previously reported ones with heterocyclic compounds containing the sequence NH—CO—NH—CO. In the presence of water, 5 is easily hydrolyzed to 6. The structures of 5 and 6 have been established by X-ray crystallography.

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Enantioselective Synthesis of Pseudomonic Acids. I. Synthesis of Key Intermediates (1982)

Schönenberger, Bernhard ; Summermatter, Walter ; Ganter, Camille

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2333-2337

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Notes: An enantioselective synthesis of key intermediates for the synthesis of the anti-microbially active pseudomonic acids A (1), B (2) and C (3) is described. D-Ribose (4) was used as starting material.

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The chemistry of thujone. VIFor Part V, see[2].. Thujone as a chiral synthon for the synthesis of optically active steroid analogues (1982)

Kutney, James P. ; Grice, Peter ; Pascoe, Keith O. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2345-2354

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Notes: The thujone derived enone 1 is converted in one step to the pentacyclic compound 4. The structure of 4 was determined by X-ray diffraction analysis. The acid-catalyzed cyclopropane-ring opening of 4 and of the model compound 9 are described.

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Mitteilungen - Communication (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2363-2364

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Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

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URL: http://dx.doi.org/10.1002/hlca.19820650743

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Masthead (1982)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982)

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URL: http://dx.doi.org/10.1002/hlca.19820650801

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Photochemical Reactions 127th Communication126th Communication, see [1]Photochemistry of Epoxy-enones: Intramolecular Trapping of a Carbonyl YlidePresented in part at the IXth IUPAC Symposium on Photochemistry, July 25-30 1982, Pau, FranceDedicated to Prof. T. Reichstein on the occasion of his 85th birthday (1982)

Ohta, Shigeru ; Frei, Bruno ; Jeger, Oskar

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2363-2371

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Notes: On 1n, π* -excitation 5, 6-epoxy-2-hydroxy-5, 6-dihydro-β-ionone ((E)-4) shows the typical behaviour of a, β-unsaturated γ, δ-epoxy ketones undergoing primarily C(γ), O-cleavage of the oxiran. However, 1π, π*-excitation of (E)-4 leads to enol ether 10 which is formed by intramolecular insertion of the hydroxyl group of the ylide c.

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A Note on Intramolecular Photochemical Cycloaddition of N-substituted DimethacrylimidesSynthesis and reactivity of Compounds with Cyclobutane Ring(s), Part 18. For Part 17, see [1]. For preliminary communication, see [2].Dedicated to Prof. Dr. Oskar Jeger on the occasion of his 65th birthday (1982)

Alder, Alex ; Bühler, Niklaus ; Bellus, Daniel

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2405-2412

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Notes: The intramolecular photochemical [2+ 2]-cycloaddition of N-substituted dimethacrylimides 1a and 1c, respectively, proceeds under conditions of direct irradiation (λ = 254 nm) as well as triplet photosensitization highly regioselectively yielding predominantly the «cross» bonding (head-to-tail) cycloadducts 3a and 3c, respectively, with a 3-azabicyclo [3.1.1]heptane ring system.

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Consecutive Application of the α-Alkynone Cyclization: Total Synthesis of (±)-Δ9(12)-CapnellenePresented by J. Huguet at the meeting of the Swiss Chemical Society in Berne, October 15, 1982. (1982)

Huguet, Joan ; Karpf, Martin ; Dreiding, André S.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2413-2421

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Notes: The synthesis of the (±)-form of the marine sesquiterpene (-)-Δ9(12)-capnellene (1) by double application of the a-alkynone cyclization is described. Starting with 2, 2, 5-trim ethylcyclopentanone (2), the elaboration of the tricyclo [6.3.0.02,6]undecane C-skeleton of 1 proceeded through the a-alkynone 3, which was cyclized thermally to the bicyclo [3.3.0]octenone 4. For the anellation of the third five-membered ring, 4 was transformed into the a-alkynone 5 and the latter cyclized thermally to a mixture of the angular triquinenone 6 and the linear triquinenone 7. The last steps in the synthesis of (±)-Δ9(12)-capnellene (1) were then accomplished from 7 by known methods.

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Norbornanes. Part 10. Solvolysis of the Stereoisomeric 6-Cyano-2-norbornyl p-Toluenesulfonates. A Correction (1982)

Grob, Cyril A. ; Herzfeld, Danielle

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2443-2447

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Notes: The solvolysis products of the stereoisomeric 6-cyano-2-norbornyl p-toluene sulfonates 1-4 (R = CN) in dioxane/water 7 : 3 have been determined. In contrast to an earlier report the 6exo-cyano-2exo-norbornyl p-toluenesulfonate (1; R=CN) yields 30% of the 2endo-alcohol 9 (R=CN) beside the 2exo-alcohol 10 and the norbornenes 12 and 13. The results confirm that - I substituents at C(6) reduce 1,3-bridging in the intermediate norbornyl cation and hence its rate of rearrangement. The relatively high rate constants for some 6-fluoro- and 6-cyano-2exo norbornyl p-toluenesulfonates are ascribed to C, C-hyperconjugation assisted by the conjugative effects of the 6-fluoro and cyano substituents.

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URL: http://dx.doi.org/10.1002/hlca.19820650809

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Synthesis of Unbranched 4-Alkylbenzaldehydes (1982)

Osman, Maged A.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2448-2449

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Notes: The preparation of unbranched 4-alkylbenzaldehydes free of positional and branched-chain isomers by different methods is described. A one-step preparation of the aldehydes is reported which involves the -direct hydrogenation of a Friedel Craft's complex in the presence of Pd/C catalyst.

Additional Material: 1 Tab.

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A Further Synthetic Approach to the Adamantane Isomer 2, 5-Trimethylenenorbornane (Tricyclo [5.3.0.03,9]decane, 4-Homotwistbrendane) (1982)

Känel, Hans-Ruedi ; Ganter, Camille

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2453-2457

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Notes: A further synthetic approach to 2, 5-trimethylenenorbornane (1; tricycle [5.3.0.03,9]decane, 4-homotwistbrendane), a member of the «adamantaneland», is described starting from methyl 5-oxo-2endo-norbornanecarboxylate (5). The required C2-chain was introduced by a Wittig-Horner reaction and the ring closure of the trimethylene bridge achieved by an acyloin condensation.

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URL: http://dx.doi.org/10.1002/hlca.19820650812

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‘Non-Koopmans’ States in Stilbene Cations and a Remarkable Example to the «SDT-Equation»: Indeno [2,1-a]indene'Studies on Radical Ions', Part XII. For Part XI see [1] (1982)

Haselbach, Edwin ; Klemm, Urs ; Gschwind, Rudolf ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2464-2471

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Notes: The radical cations of indeno [2, 1-a]indene (1), stilbene (2) and 3, 5, 3', 5'-tetramethylstilbene (3) were prepared by γ-irradiation of the neutral precursors in an electron-scavenging matrix at 77 K. Their electronic spectra were recorded and compared to the photoelectron spectra (PE.) of the neutral precursors. The results show that either the fourth or the fifth excited doublet state of the cations is of «Non-Koopmans» type, with specific doublet energy (D) D (2Bg)=2.74 eV (1+), =2.59 eV (2+), =2.49 eV (3+). Remarkably, 1+ possesses two electronic states in the 2.7-2.8 eV energy range: 2Au («Koopmans»-type) and 2Bg («Non -Koopmans»-type). The «SDT»-equation \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm D} = \sqrt {{\rm S} \cdot {\rm T}} $\end{document} approximately connecting excited singlet (S) and triplet (T) states of a neutral alternant system with the excited doublet (D) states of its radical cation - provided e-promotion occurs For all three excited states between the same (paired) orbitals-is satisfyingly exemplified by 1: S1 = 3.92 eV and T1= 2.06 eV for 1, D4 or 5=2.74 eV for 1+.

Additional Material: 6 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19820650814

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Rearrangements Involving C8H8F-Cations of the Cage Type (1982)

Jefford, Charles W. ; Mareda, Jiri ; Blaudzun, Jean-Pierre ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2476-2480

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Notes: The homo-l, 4 adduct obtained from difluorocarbene and bicyclo [2.2.1]hepta-2, 5-diene (1) was treated successively with HCl, FSO3H and SbF5 in SO2ClF at low temperature. The protic acids underwent electrophilic addition to the cyclopropane part of 1, giving the corresponding derivatives. However, in FSO3H at - 50°, protonation of the gem-difluoro grouping also occurred to give the 2-fluoro-6-fluorosulfonylbicyclo [3.2.1]oct-2-en-3-yl cation. The reaction of 1 with SbF5 at -78° led initially to the formation of the 2-fluorobicyclo [3.2.1 ]octa-2, 6-dien-4-yl cation, which rearranged to 4-fluorotricyclo [5.1.0.05,8]oct-3-en-2-yl cation at -40°. These rearrangements are discussed in the light of those expected for C8H8F square pyramidal cations.

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Desoxy-nitrozucker. 3. Mitteilung2. Mitteilung:[1].. Synthese von Ketosen durch Kettenverlängerung von 1-Desoxy-1-nitro-aldosen. Nucleophile Additionen und Solvolyse von Nitroaethern (1982)

Aebischer, Bernard ; Bieri, Jost H. ; Prewo, Roland ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2251-2272

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Notes: Synthesis of Ketoses by Chain Elongation of 1-Deoxy-1-nitroaldoses. Nucleophilic Additions and Solvolysis of Nitro EthersA method for the preparation of chain elongated uloses based upon the base-catalyzed addition of 1-deoxy-1-nitroaldoses to aldehydes and Michael acceptors and subsequent solvolytic replacement of the nitro group by a hydroxy group is described. Thus, addition of 1, 3 and 9 to formaldehyde, followed by solvolysis gave the chain elongated ulose derivatives 2, 8 and 10 (63-76%), respectively. The configuration at the anomeric center of the addition products was deduced from 13C-NMR. spectra and mutarotation. In the case of 3, the primary addition products 4 and 6 were isolated and acetylated to 5 and 7. The nitro derivatives 4-7 do not follow Hudson's rule of isorotation. Addition of 1 to benzaldehyde (44%) and to nonanal (74%) preceded with a small degree of diastereoselectivity to give 15a/15b, and 11/12, respectively. The configuration of the secondary hydroxyl group of 12 was determined by correlation with methyl 2-hydroxydecanoate (14). Addition of 1 to the galacroaldehyde 16 gave a single compound 17 (78%). The structure of this dodecosulose was determined by X-ray crystallography. Solvolysis of the acetylation product 18 in formamide gave the hemiacetal 19 (69%). Michael addition of 1 to acrylonitrile, methyl vinyl ketone and cyclohexenone under solvolytic conditions gave the hemiacetals 27, 30 and 31a,b (49%, 71% and 76%, respectively). Under non-solvolytic conditions (Bu4NF), 1 reacted with acrylonitrile, and crotononitrile to give the anomeric nitro ethers 23 and 24 (67%) and 25 and 26 (84%). respectively. Similarly. 3 added to acrylonitrile to give 28 and 29 (55%, 4:1). This reaction appears to proceed under kinetic control. Addition of 1 to ethyl propiolate and solvolysis yielded the unsaturated spirolactone 32 (50%) and the hemiacetal 33 (17%). Hydrogenation of 32 gave the saturated spirolactone 34 (100%) which was also obtained from 1 and methyl acrylate (63%). Addition of 1 to dimethylmaleate gave the unsaturated ester 35 (48%).

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Structure-Activity Relationship of Oxygenated Morphinans. VII. 5-Methylated and 14-Hydroxy-substituted Agonists and Antagonists of the 4-Hydroxy- and 3, 4-Dioxygenated 6-Morphinanone Series (1982)

Brossi, Arnold ; Atwell, Louise ; Jacobson, Arthur E. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2394-2404

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Notes: Several morphinanone agonists differently substituted at C(3), C(4), C(5) and C (14) and antagonists of the 4-hydroxy and 3, 4-dimethoxy series were prepared by conventional chemistry. It was demonstrated that the oxygenation pattern in the bay-area, encompassing C(3) and C(4), is important. Alkylation at C(5) or hydroxylation at C(14) lowered the potency of the compounds. The most potent agonist was found to be the N-phenethyl-substituted ketone 27, which was six times more potent than morphine in the hot-plate assay. The 3, 4-methylenedioxy-substituted ketone 9 was about 20 times less potent than its 3, 4-dimethoxy congener. An X-ray analysis of 9 and a representative agonist showed that the stereochemical features in the bay-area were similar and could not be used to explain this difference.

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Intramolecular Transfer of Excitation Energy, Complexation with Metal Ions, and Interactions with Liposomes of Cyclo [tryptophyl-sarcosyl-sarcosyl-N∊-dansyllysyl-prolyl] (1982)

Kimura, Shunsaku ; Imanishi, Yukio

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2431-2442

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Notes: A cyclic pentapeptide containing an energy donor group and an energy acceptor group within the molecule, cyclo [Trp-Sar-Sar-Lys (DNS)-Pro], was synthesized. Its conformation, complexation with metal ions, intramolecular energy transfer, and interaction with liposomes were investigated. The precursor, cyclo [Trp-Sar-Sar Lys (Z)-Pro], contained one cis-sarcosyl peptide bond and a β-turn in which the Pro-residue occupied the 3rd position. This cyclic pentapeptide formed a complex selectively with Ba2+ and its binding constant in 95% aqueous methanol solution was 2.0 × 103 1 · mol-1. The intramolecular energy-transfer efficiency of cyclo [Trp-Sar-Sar-Lys (DNS)-Pro] was almost constant between - 60° and 40° in ethanol, while it increased at temperatures lower than 34° in liposomes as a result of the pre-transition of the lipid assembly. On the other hand, the intramolecular energy transfer efficiency of cyclo [Trp-Sar-Sar-Lys (DNS)-Pro] decreased upon complexation with Ba2+.

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URL: http://dx.doi.org/10.1002/hlca.19820650808

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Water Relaxation Measurements on Semiquinones of Various Flavoproteins (1982)

Visser, Antonie J. W. G. ; De Wit, Jan L. ; Müller, Franz ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2422-2430

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Notes: The water relaxation rates of several flavoproteins in the semiquinone state have been investigated by the spin echo technique. The results indicate a rather unspecific interaction between water and the protein-bound flavosemiquinones. An average interaction distance of 0.3-0.5 nm has been estimated. From the temperature dependence of the rate constants the free energy of activation for proton exchange is calculated to be about 17 kJ/mol. The rate of proton exchange is around 1011 s-1 for the flavosemiquinones investigated are accessible to water regardless of their ionic state.The large difference in relaxation rates of water protons between D- and L- amino-acid oxidases is noticeable. Oxynitrilase exhibits the highest whereas Azotobacter vinelandii flavodoxin shows the lowest water relaxation rate of the flavoproteins studied. The results are discussed in relation to the visible-light absorption properties of the flavoproteins.

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Spectroscopic Investigation of Anhydrous Solutions of Europium Perchlorate and Europium Nitrate in N, N-DimethylformamidePart 3 of the series «FT.-IR, and Fluorometric Investigation of Rare-Earth and Metallic Ion Solvation'; Part 2, cf. [1] (1982)

Bünzli, Jean-Claude G. ; Yersin, Jean-Robert

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2498-2506

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Notes: Anhydrous solutions of Eu(ClO4)3 and Eu (NO3)3 0.05m in N, N-dimethyl formamide (DMF) are investigated by means of conductometric measurements, vibrational spectroscopy, electronic absorption and emission spectra, and fluorescence lifetime determinations. Eu (ClO4)3 is completely dissociated and no inner-sphere interaction takes place between ClO4 and Eu3+ ions. The solvated species Eu (DMF)x3+ has a C2v-symmetry and x is probably equal to 8.A more complicated situation occurs for Eu (NO3)3, the solutions of which contain at least three different solvates; the predominant species is [Eu (NO3)2 (DMF)x-4]+ (≈80% of the total Eu-concentration) and it is more stable than the mononitrato complex [Eu (NO3) (DMF) X-2]2+; the neutral complex Eu (NO3)3 (DMF) x-6 is also present, as can be inferred from a high-resolution analysis of the 5D0→7F0 emission band. The absence of emission from the excited 5D1-level can be rationalized in terms of an efficient non-radiative deexcitation path through a vibrational mode of the DMF-molecules bonded to the central metal ion.

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URL: http://dx.doi.org/10.1002/hlca.19820650819

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On the Mechanism of the α-Alkynone Cyclization: A Theoretical Study (1982)

Kaneti, José ; Karpf, Martin ; Dreiding, André S.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 65 (1982), S. 2517-2525

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The acetylene → carbene rearrangement of three model a-alkynones, namely propynal (1a), 2-butynal (1b) and butynone (1c) is studied by ab initio double-zeta, double-zeta plus polarization and double-zeta plus self-consistent electron pairs calculations. Transition states are located by force-gradient geometry optimization. Calculated minimum energy reaction paths reveal substituent effects on the activation parameters, which indicate that a H-atom or an alkyl group competes favorably with an acyl group in the [1,2]-shift from a-alkynones 1 to the corresponding acylvinylidenes 5.

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URL: http://dx.doi.org/10.1002/hlca.19820650821

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The He(Iα) Photoelectron Spectra of the Perfluoroderivatives of Trisannelated Benzenes and Tetrakisannelated Cyclooctatetraenes (1984)

Heilbronner, Edgar ; Wirz, Jakob ; Soulen, Robert L.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 47-53

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Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The He(Iα) photoelectron (PE) spectra of tris(perfluorocyclobuta)benzene 4(F)3,3,4,4,7,7,8,8,11,11,12,12-Dodecafluorotetracyclo[8.2.0.02,5.06,9]dodeca-1,5,9-triene, tris(perfluorocyclopenta)benzene 5(F)1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-Octadecafluoro-2,3,4,5,6,7,8,9-octahydro-1H-trindene., tetrakis(perfluorocyclobuta)cyclooctatetraene 6(F)3,3,4,4,7,7,8,8,11,1l,l2,l2,l5,15,16,16-Hexadecafluoropentacyclo[12.2.0.02,5.06,9.010,13]hexadeca-1,5,9,13-tetraene., and of tetrakis(perfluorocyclopenta)cyclooctatetraene 7(F)1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12-Tetracosafluoro-1,2,3,4,5,6,7,8,9,10,11,12-dodeca-hydrotetracyclopenta[a,c,e,g]cyclooctene. are reported. A tentative assignment of the PE spectra is derived by empirical correlation with those of relevant reference compounds. The results suggest that 6(F) retains the D4h-conformation in the gas phase, i.e. A conformation with a planar cyclooctatetraene ring, as observed in the crystal. All four compounds exhibit a sharp increase of their first ionization energies, relative to the corresponding parent hydrocarbons, due to the perfluoro effect.

Additional Material: 1 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19840670107

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Transition metal complexes with bidentate ligands spanning trans-positions. Part XIVPart XIII: see [1].. Some complexes of 2,11-bis(diphenylphosphinomethyl)benzo[c]phenanthrene with platinum (0) and their reactivities (1984)

Boron-Rettore, Patrizia ; Grove, David M. ; Venazi, Luigi M.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 65-72

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The ligand 2,11-bis(diphenylphosphinomethyl)benzo[c]phenanthrene (1) has been used to prepare complexes of the type [PtL(1)] (L = C2H4, CH2=CH—CO2Me, PhC≡CPh, MeC≡CMe, MeO2CC≡CCO2Me, (i-Pr)O2CC≡CCO2(i-Pr), Ph3P and CO). It is shown that these complexes are less labile than the corresponding species [PtL(Ph3P)2]. The preparation of complexes trans-[PtX(R)(1)] by oxidative addition of RX (RX = PhCH2Br and Mel) to [Pt(C2H4)(1)] is described. The isolation of [PtO2(CH3)2CO(1)] is also reported.

Additional Material: 3 Tab.

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URL: http://dx.doi.org/10.1002/hlca.19840670109

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Intermolecular Electron Spin Transfer between Naphthalene π-Systems Separated by a Variable Number of Spirobonded Cyclobutane Rings, An. ESR and ENDOR Study (1984)

Gerson, Fabian ; Huber, Walter ; Martin, Wiliam B. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 416-424

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The radical anions of the compounds N1N, N3N and N5N, in which two naphthalen π-systems are separated by 1, 3 and 5 spirobonded cyclobutane rings, respectively, and tha tof the reference compound N1, containing one naphthalene π-system and one cyclobutane ring, have been studied by ESR and ENDOR spectroscopy under a variety of experimental conditions. The intramolecular electrons spin transfer between the two π-moieties in N3N.⊖ and N5N.⊖ is slow on the hyperfine time-scale, irrespective of the applied conditions. It is also slow in N1N.⊖, except for media of high solvating power. In such media, with a slight reduction of N1N to its radical anion, a paramagnetic species is observed, the hyperfine data for which are consistent with N1N to its radical anion, a paramagnetic species is observed, the hyperfine data of which are consistent with N1N.⊖, undergoing a fast intramolecular electron spin tansfer. The ESR and ENDOR spectra of this species are superimposed on those characteristic of a slow transfer. It is suggested that the fast and slow transfer involve the syn- and anti-conformations, respectively, since the distance, r, between the two naphthalene π-systems of N1N.⊖ is considerably shorter in the former than in the latter (r = 740 vs. 880 Pm for the distance between the centres of the π-systems). Glassy solutions of exhaustively reduced N1N display signals of the dianion triplet state, whereas no such signals are found for N3N and N5N. The zero-field splitting parameter, D, is 4.7 mT, corresponding to r ≈ 480 pm.

Additional Material: 5 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19840670210

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The mass spectra of organic compounds. 7th Communication6th Communication, see [1].. 4,4-Dimethyl-1-pentene (1984)

Marques, José Carlos Antunes ; Falick, Arnold ; Heusler, Andréas ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 425-433

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Loss of CH3., CH4, C2H4, C3H5., C3H6 and C3H7 from the molecular ions of a number of 13C-labeled analogs of 4,4-dimethyl-1-pentene was studied both in normal (source) 70-eV electron impact (EI) spectra dn in metastable spectra. For loss of CH3. in the source, 96% of the methyl comes frm positions of 5, 5′ and 5″, while the remainder comes from position 1. In the metastable spectra, loss of C-1 (16%) and C-3 (9%) is increasing in importance. The loss of ethylene is a particular case: either C-1 or C-3 are lost with any other C-atom from positions 2,5,5′, and 5″ (8 × 10%) in the metastable spectra, the probability for simultaneous loss of C-1 and C-3 being 6%. If C-1 seems to these two positions become completely equivalent in the metastable time range. The T-values (kinetic energy release) for the different positions show small, but statisticaly different values and a small isotope effect. Loss of C3H5 (allylic cleavage) is 100% C-1, C-2 and C-3, i.e., no evidence for skeletal rearrangement is seen. This is also true for loss of C3C6 (McLafferty rearrangement) within the source, but in metastable decay the other positions gain in importance. The neutral fragment C3H7. appears to be the the result of consecutive loss of CH3. and C3H4, rather than a one-step loss of propyl radical or the inverse reactions sequence. No metastable reaction can be seen for this reaction. Decomposition of labeled C6H11+ and C5H10+ secondary ions occurs in an essentially random fashion.

Additional Material: 6 Tab.

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URL: http://dx.doi.org/10.1002/hlca.19840670211

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Synthese von para-substituierten phenyl-terpyridin liganden (1984)

Spahni, Werner ; Calzagerri, Gion

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 450-454

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Up to now the synthesis of para-substituted phenyl-terpyridine ligands was difficult with respect to the purification of the reaction products. We have found that these compounds can easily be isolated as hydrobromides from acetic acid. Starting from the hydrobromides the purification turned out to be easy. Synthesis of para-substituted Cl-, Br-, H3C-, H2BrC-, HO- 2,6-Bis(2-pyridyl)-4-phenylphyridine is reported.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19840670214

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Complexation de l'argent(I) par des teramines cycliques (1984)

Suet, Elisabeth ; Laouenan, André ; Handel, Henri ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 441-449

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Complexation of Silver(I) by Cyclic TetraminesThe nature of Ag(I)-complexes with 1,4,8,11-tetraazacyclotetradecane (1), 1,5,9,13-tetraazacyclohexadecane (2) 1,5,10,14-tetraazacyclooctadencane (3) and 1,6,11,16-tetraazacycloeicosane (4) is studied. The effect of ring size on disproportionation of the Ag() cation in the presence of ligand is reported. The stability of Ag(I)-complexes with 3 and 4 in aqueous solution is determined by means of potentiometric titration.

Additional Material: 5 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19840670213

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Mitteilungen - Communications (1984)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 625-627

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19840670231

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Masthead (1984)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984)

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19840670301

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Radikalionen von überbrückten [14] Annulenen. Untersuchungen zum Frontorbitaleinfluss auf Reaktivität und Bindungszustand (1984)

Huber, Walter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 625-639

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Radical Ions of Bridged [14] Annulenes. Investigations on the Influence of Frontier Orbitals on Reactivity and BondingThe radical anions and the radical cations derived from trans-15, 16-dimethyl-1, 4:8,11-ethandiyliden[14]annulene (6), trans-15-methyl-1,4:8,11-ethandiyliden[14]annulene (7) and cis-15, 16-propano-1,4:8,11-ethandiyliden[14]annulene (8) are described. The hyperfine data of the radical anions 6, 7 and 8 resemble those of the structurally related radical anions of trans-10b, 10c-dimethyldihydropyrene (4) and trans-10b, 10c-dihydropyrene (5). This finding leads to the conclusion, that the change in the relative arragement of the saturated bridge within the fourteen-membered π-perimeter by passing from 4 (5) to 6 (7, 8) does not in fluence the energetic sequence of the lowest unoccupied molecular orbitals. The behavior of 6 and 7 towards oxidation parallels the photochemical reactivity of 4. The hyperfine coupling constants of the radical cations derived from 6 and 7 indicate that the removal of an electron is accompanied by an isomerization of the molecular framework. The investigation of the electron transfer process gby cyclic voltammetry supports these findings. The radical cations prefer the cyclophane-like structures 6a and 7a, in which the central σ-bond (C(15)-C(16) bond) is broken.

Additional Material: 7 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19840670302

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Photochemistry of 2-(Trifluoromethyl) cyclohexanone (1984)

Semisch, Christoph ; Margaretha, Paul

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 664-668

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The photochemical behaviour of the title compound 1a is compared to that of the non-fluorinated parent ketone 2-methylcyclohexanone (1b). Substitution of the CH3- group on C(2) by a trifluoromethyl group strongly enhances 2H- and RH- reduction product formation in cyclohexane or 2-propanol and oxetane formation in the presence of 2-methylpropene as olefinic component. Under all these conditions 1b exclusively undergoes a-cleavage, a process observed for 1a only in non-reducing solvents as benzene or tert-butyl alcohol.

Additional Material: 2 Tab.

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URL: http://dx.doi.org/10.1002/hlca.19840670305

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Synthesis of Optically Pure Compounds by Enantiotopically Differentiating Monoacetalization of Prochiral Diketones. Part II. Fragmentation of β-Keto-AcetalsPart I: [1]. These results, which have been presented in part at the ‘Herbstversammlung der Schweizerischen Chemischen Gesellschaft’, October 16, 1981, in Bern, are comprised in the Ph. D. thesis of P. M. [2]. The nomenclature and classification of stereodifferentiating reactions proposed by Izumi & Tai [3] are used in this communication (1984)

Duthaler, Rudolf O. ; Maienfisch, Peter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 832-844

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: Treatment of β-keto-acetals, derived from non-enolisable β-diketones, with sulfonic acids in boiling benzene resuots in a smooth retro-Claisen-type fragmentation. The acetal-C-atom is thereby transformed into a carboxylic ester via a dialkoxycarbenium ion, which is dealkylated by the sulfonate counter-ion. Application of this reaction to the diastereomeric monoacetals 3 and 4, derived from cis-9-methyl-decalin-1,8-dione (1), followed by transesterification with CH3OH, yields optically pure 4-(2′-methyl-3′-oxocyclohexyl)butyrate 9 ((+)-9 from 3, (-)-9 from 4) and the monosulfonate of Meso-2,3-butanediol (-)-13 (Scheme 2). Unexpectedly, this cleavage proceeds as well with monoacetal 26, obtained by acetalization of trans-9-methyl-decalin-1,8-dione (27) with 2,2-dimethyl-1,3-propanediol (Scheme 7). Some attempts, aiming at an isomerization of the cis- and trans-decalin derivatives 3 and 24, or 25 and 26, via the postulated carboxonium intermediate, were not successful.

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URL: http://dx.doi.org/10.1002/hlca.19840670324

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Preparation of Bicyclo[3.3.0]octane-2,8-dione- and Declain-1,8-dione-DerivativesThese results are comprised in the Ph. D. thesis of P. M. [1] (1984)

Duthaler, Rudolf O. ; Maienfisch, Peter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 856-865

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Alkylation of bicyclo[3.3.0]octane-2,8-dione (1), which is prepared by a modification of the procedure described in the literature, gives the methyl- and propynyl-derivatives 6 and 7 (Scheme 1). In addition to the method described previously (Scheme 2), 9-methyl-cis-decalin-1,8-dione 9 is obtainable stereoselectively either by cyclization of keto-acid 16, or by aldol cyclization of keto-aldehyde 26 and oxydation of the resulting alcohols 24 and 25 (Scheme 4). The β-keto-alcohols 24 and 25 undergo a base-catalyzed isomerization; the trans-decalin isomers 27 and 28 are not detected in this equilibrium mixture (Schemes 4 and 5)l. Monoreduction of cis-dione 9 gives the endo-alcohol 25, while 27 is the favored product of the reductin of trans-dione 10 (Scheme 4). Optically pure (+)-25 can be prepared from (9S,10R)-monoacetal 29 (Scheme 5).

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Synthesis of a S-(Carboxymethyl)cysteine Analog of (L-2-Amino-6-adipyl)-L-cysteinyl-D-valine and its Cell Free Biosynthetic Conversion into 6-[2-(D-2-Amino-2-carboxyethyl)thio) acetamido]penicillanic Acid (1984)

Shields, James E. ; Campbell, Charles S. ; Duckworth, Dale C. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 870-875

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: A new tripeptide (dimer), bis[(L-cysteine-S-acetyl)-L-hemicystinyl(S2 → S2)-D-valine] (6) was synthesized by coupling N-(tert-butoxycarbonyl)-S-carboxymethyl-L-cysteine benzyl ester (1) with S-trityl-L-cysteinyl-D-valine benzyl ester and subsequent removal of the protecting groups. After reduction of the disulfide, the free tripeptide Cys (CH2CO-Cys-D-Val) (Ib) was used as a substrate of isopenicillin-N synthetase in a cell-free conversion to 6-[2-((D-2-amino-2-carboxyethyl)thio)acetamido]penicillanic acid (IIa).

Additional Material: 3 Ill.

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URL: http://dx.doi.org/10.1002/hlca.19840670328

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The Synthesis of cis- and trans- 7-Phenylkacetamido-O-2-isocephemO-2-Isocephems are alternatively called isooxacephems (1984)

Hakimelahi, Gholam Hosein

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 902-905

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The synthesis of the title compounds is described.

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URL: http://dx.doi.org/10.1002/hlca.19840670331

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Erratum (1984)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 927-927

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

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URL: http://dx.doi.org/10.1002/hlca.19840670334

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Absolute Conformation and Configuration of (2S, 3S)-3-Acetoxy-5-(dimethylaminoethyl)-2-(4-methoxyphenyl)-2,3-dihydro-1,5-benzothiazepin-4(5H)-one Chloride (Dilthiazem Hydrochloride) (1984)

Kojić-Prodić, Biserka ; Ružić-Toroš, ŽIva ; Šunjić, Vitomir ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 916-926

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: Resolution of racemic cis-3-(2-aminophenylthio)-2-hydroxy-3-(4-methoxyphenyl) propionic acid (2) via the cinchonidine salt 3, and brucine salt 4, isolation of the calcium salts (+)- and (-)-5, as well as their cyclization to enantiomeric 1,5-benzothiazepines (+)- and (-)-1, are described. X-Ray single-crystal analysis reveals (2S, 3S) absolute configuration of (+)-1 on the basis of tentative comparison of CD data with those for the 1,4-benzodiazepine derivative (+)-8 of known absolute configuration.

Additional Material: 4 Ill.

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Masthead (1984)

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984)

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

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URL: http://dx.doi.org/10.1002/hlca.19840670401

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Synthese und Struktur von Zink-Komplexen von 2-Amino-1-azetinen (1984)

Stierli, Friedrich ; Prewo, Roland ; Bieri, Jost H. ; [et al.]

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 927-933

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Notes: Synthesis ad Structure of Zinc Complexes of 2-Amino-1-azetinesThe 2-dimethylamino-3,3-dimethyl-1-azetines 7a and 7b have been synthesized in analogy to the procedure reported by Ghosez et al. [1] (Scheme). The crystal structure of 1-benzhydryl-azetidindimethyliminium chloride 5a, a precursor of azetine 7a, has been established by X-ray diffraction analysis. Treatment of azetines 7a and 7b with ZnBr2 in CH2Cl2/MeCN yielded tetrahedral bis (azetine)dibromozinc complexes 8a and 8b, respectively (Scheme 2). The molecular structure of 8a has been determined by X-ray diffraction analysis too.

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Enantioselective synthesis of (+)- and (-)-cis-2-methyl-4-propyl-1,3-oxathiane and their olfactive properties (1984)

Pickenhagen, Wihelm ; Brönner-Schindler, Helene

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 947-952

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: The enantioselective synthesis of (+)- and (-)-cis-2-methyl-4-propyl-1,3-oxathine 8 and 9 form (E)-2-hezen-1-ol (1) as common starting material is described. The two enantiomeric forms exhibit different organoleptic properties.

Additional Material: 2 Tab.

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URL: http://dx.doi.org/10.1002/hlca.19840670405

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Aliphatic Liquid Crystals with Positive Dielectric Anisotropy (1984)

Osman, Maged A. ; Huynh-Ba, T.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 959-963

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Source: Wiley InterScience Backfile Collection 1832-2000

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Notes: Cyanothyl-subsituted cylohexyl cyclohexanoates, bi(cyclohexanes) and phenyl cyclohexanes were synthisized. Their mesmorphic behaviour is compared to that of the corresponding cyano derivatives. (Cyanoethyl)cyclohexyl cyclohenxanoates show mesmorphic properties in contrast to the corresponding cyano derivative. Separation of the cyano substituent from the rigid core of an anisotropic aliphatic compound by methylene groups enhances the thermodynamic stability of the mesophase. In aromatic compound, the cyanoethyl group leads to lower clearing points. These phenomena are attributed to teh influence of steric effects on the packing density and to the dependence of the clearing point on molecular association.

Additional Material: 2 Tab.

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URL: http://dx.doi.org/10.1002/hlca.19840670407

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Monohaptenic Nα-Benzoyl-L-lysine Derivatives as Anaphylactogens: the Importance of the Unsubstituted Carboxyl Group (1984)

Guenin, Raymond ; Schneider, Conrad H.

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 1000-1002

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Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Nα-L-Iysine with a 2-carboxy-4, 6-dinitrophenyl (Dncp) haptenic group on the ε-amino function is a potent anaphylactogen in the guinea pig. We prepared Nε -Dncp- Nα-benzoly-L-Iysinamide and Nε-Dncp-Nα-benzoyl-L-lysyl-1-aminopropane where the carboxyl group of Iysine is blocked. Both compounds were non-elections of anaphylaxis.

Additional Material: 1 Tab.

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URL: http://dx.doi.org/10.1002/hlca.19840670411

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C45- und C50-Carotinoide. 2. Mitteilung. Synthese von optisch aktiven acyclischen C15-Endgruppen (1984)

Kramer, Andreas ; Pfander, Hanspeter

New York, NY : Wiley-Blackwell

Helvetica Chimica Acta 67 (1984), S. 21-28

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ISSN: 0018-019X

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: C45- and C50-Carotenoids. Synthesis of Optically Active Acyclic C15-End GroupsThe optically active C15-end groups (S)-12, (S)-13 and (R)-14 were prepared from the C12-synthon (S)-11 in good chemical and optical yield. These C15-end groups are suitable compounds for the synthesis of optically active C45- and C50-carotenoids.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/hlca.19840670104

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Paper (German National Licenses)

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