ISSN:0165-0513    

DOI:10.1002/recl.19811000102

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19811000103

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractReaction of 1‐(chloromethylthio)‐1‐alkynes (RCCSCH2Cl, R  alkyl or phenyl) with an alkali metal sulfide, selenide or telluride gives 4‐substituted 1,3‐dithioles together with the corresponding 1,3‐thiaselenoles and 1,3‐thiatelluroles in good yields. The compounds RCCSCH2Cl can be obtained either from lithium alkynethiolates (RCCSLi) and BrCH2Cl or from alkynyllithium (RCCLi) and chl

ISSN:0165-0513    

DOI:10.1002/recl.19811000104

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

Abstract2,2‐Dialkoxy‐3,4‐dihydropyrans (3) can be obtained under mild conditions and in good yields from ketene acetals (1) and α,β‐unsaturated carbonyl compounds (2) in the presence of ZnCl2. At low temperatures (<−20°C) the reaction between1and2proceeds as a (2 + 2)‐cycloaddition, leading to an oxetane (4), which can sometimes be isolated by neutralisation of the Lewis acid. At higher temperatures, however, the oxetanes decompose into the starting compounds, eventually leading to the thermodynamically more stable dihydropyrans. The cycloadditions of tetramethoxyethene (1a) with2, having no substituents at the β‐carbon atom, yield a cyclobutane derivative as the low temperature product; in cycloadditions of α,β‐unsaturated esters this is the final product. Cycloadditions of 2‐chloroketene acetal (1e) lead in some cases to 2:1 adducts. The deviating behaviou

ISSN:0165-0513    

DOI:10.1002/recl.19811000105

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractAliphatic as well as aromatic acid chlorides are reduced smoothly into aldehydes at room temperature and atmospheric pressure by hydrogenation, using palladium on carbon as the catalyst, acetone or ethyl acetate as solvent and ethyldiisopropylamine as hydrogen chloride acceptor. The reaction has a high selectivity and under the conditions used, no over‐reduction nor reduction of aromatic rings, of nitro and chloro substituents in benzoyl chlorides, or double bonds in cinnamoyl chlorides, was observed. The selectivity is probably the result of a combination of factors, such as selective adsorption of the acid chloride on the catalyst (with respect to the aldehyde) and partial poisoning of the catalyst surface by co‐adsorption of ethyldiisopropylamine and its hydrochlor

ISSN:0165-0513    

DOI:10.1002/recl.19811000106

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractPhenylthallium(III) bis(trifluoroacetate) (PhTlX2) reacts with excess of anisole at 70‐80°, yielding mainly the three isomeric anisylphenylthallium(III) compounds (o‐, m‐, p‐AnPhTlX). Monoanisylthallium(III) derivatives (o‐,m‐,p‐AnTlX2) are obtained only in the presence of excess of HX. The slow transthallation reaction of chlorobenzene requiring the presence of HX leads to theo‐, m‐, p‐ClC6H4TlX2isomers rather than to diarylthallium(III) compounds. The three isomeric anisylphenylthallium(III) compounds (o‐, m‐, p‐AnPhTlX) readily undergo exchange and isomerization reactions with anisole in the presence ‐ or more slowly in the absence ‐ of HX. Similar processes were observed with chlorobenzene but only in the presence of HX. (p‐Chlorophenyl)phenylthallium(III) trifluoroacetate is much less reactive, both towards anisole and chlorobenzene. With long reaction times the systems approach equilibrium distributions, which are approximately the same as those found for the prolonged direct thallation of the aromatic compounds. Tentative mechanistic interpretations include three different modes of formation of arylthallium bonds and draw a parallel between thallati

ISSN:0165-0513    

DOI:10.1002/recl.19811000107

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractUltraviolet spectra andpKavalues for the title compounds and theirO‐andN‐ethyl derivatives show that in each case the quinolone form is favoured in aqueous solution. The results are compared qualitatively with those for 4‐quinolone and for findings in the gas

ISSN:0165-0513    

DOI:10.1002/recl.19811000108

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractA modified synthetic route to 1,2,3‐butatrienyl ethers3is presented. It involves hydroxyalkylation of 2‐propynyl ethers with an aldehyde or a ketone, followed by trimethylsilylation of the hydroxy ether1and 1,4‐elimination of Me3SiOH from2with ethylli

ISSN:0165-0513    

DOI:10.1002/recl.19811000109

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

An examination of the mass spectra of aliphatic thioketones at 70 eV has shown some differences between these compounds and the corresponding ketones: the molecular ions of the thioketones were stronger than those of the ketones, indicating the greater ability of the sulfur atom to stabilise the radical cation; the loss of•SH was found to be a characteristic fragmentation of aliphatic thioketone

ISSN:0165-0513    

DOI:10.1002/recl.19811000110

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19811000101

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY