摘要:

Synthesis of the enantiomeric 2‐pyrrolidineacetic acids.Starting from the enantiomeric Z‐prolines (1) the title compounds9were prepared in optically pure form by using theArndt‐Eistertprocess. It could be shown by chemical correlation that the stereochemical determining step of the reaction sequence, theWolffrearrangement of the N‐acylated diazomethyl ketones5, proceeds with strict retention of configuration. Some known chiroptical methods for determination of absolute configuration were applied to the target co

ISSN:0018-019X    

DOI:10.1002/hlca.19760590602

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe reaction of 1, 2‐dibromo‐1, 2‐bis(4‐methoxyphenyl)ethane with alcohols was associated with rearrangement to give the corresponding bis(4‐methoxyphenyl)acetals. In boiling ethylene glycol 4,4′‐dimethoxy‐deoxybenzoin was also obtained due to an aldehyde‐ketone rearrangement. 4,4′‐Dimethoxybenzophenone was also formed being apparently derived from the acetals. The mechanism of formation of the aceta

ISSN:0018-019X    

DOI:10.1002/hlca.19760590603

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe deuterium isotope partition coefficient α has been determined as a function of total pressure, temperature and degree of deuteriation for methylcyclohexane/hydrogen over Ni/Al2O3. Good agreement with theory has been obtained for the dependence on temperature but not for that on total pressure or on the degree of deuteriation

ISSN:0018-019X    

DOI:10.1002/hlca.19760590604

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe kinematic viscosity of mixtures of perdeuteriated and protiated heptane has been measured between 15° and 35° and is given in polynomial form as a function of concentration and temperature. Using theMcAllisterequation to describe viscosity [4], it can be shown that the interactions between molecules containing the same or different isotopic species differ slightl

ISSN:0018-019X    

DOI:10.1002/hlca.19760590605

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractAgedVirginiatobacco was steam‐distilled and the resulting condensate investigated by chromatographic methods. This allowed identification of the bicyclodamascenonesAandBin a small subfraction from this condensate. Both these ketones, which are novel tobacco constituents, were also synthesized and a possible mechanism is proposed for their formationviaacid‐catalysed cyclization of β‐damasceno

ISSN:0018-019X    

DOI:10.1002/hlca.19760590606

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe He(II) photoelectron spectra of phosphabenzene2and arsabenzene3yield additional ionization energies in the region 17 to 20 eV. The relative intensity changes of the first three bands, compared to their relative intensities in the He(I) spectra, provide support for the previously proposed sequence of states ˜X =2B1, ˜A =2A2, ˜B =2A1. This and the angular dependence of the photoelectron band intensities in the spectra of2and3is in excellent agreement with the theoretical predictions made byvon Niessen, Diercksen&Cederbaum[

ISSN:0018-019X    

DOI:10.1002/hlca.19760590607

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe lowest states of dibenzo‐p‐quinodimethane radical cation are2B1u(7.95 eV);2B2g(8.66 eV); [2B3g,2Au, unresolved] (9.1 eV); [2B1u,2B2g, unresolved] (10.7 eV). This confirms the assignment proposed byKoenig et al.[1] for the states ofp‐quinodimethane radical c

ISSN:0018-019X    

DOI:10.1002/hlca.19760590608

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Synthesis of 1,3‐Disubstituted Adamantanes.A series of new 1‐substituted 3‐bromoadamantanes has been prepared. An improved method for the formation of cyclopropanes from olefins with diazomethane and copper salts is desc

ISSN:0018-019X    

DOI:10.1002/hlca.19760590609

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Abstract9α, 10α‐Epoxy‐hexahydrocannabinol acetate1in presence of boron trifluoride etherate rearranged to a fluoro compound6and to a ketone5, and in perchloric acid to compound11. The fluoro compound6had been considered erroneously in earlier literature as4. Compounds6and11were produced by the initial opening of the epoxide followed by the acetyl transfer from the neighbouring phenolic group.Tetrahydrocannabinol acetates2and3, on oxymercuration‐demercuration followed by reduction gave the known 9α‐hydroxy‐hexahydrocan

ISSN:0018-019X    

DOI:10.1002/hlca.19760590610

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Influence of intramolecular movements on the fluorescence quantum yield.The conditions determining the influence of the movements of different parts of molecules on the fluorescence quantum yield are shown. In the following we discuss four types of intramolecular movements that can help attain the desired fluorescent properties. In the case of methinecyanine dyes such intramolecular movements are responsible for the strong dependence of the fluorescence quantum yield on the solvent viscosity we have observed.

ISSN:0018-019X    

DOI:10.1002/hlca.19760590611

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY