摘要:

AbstractDe mème que la benzylallylsulfone3), ses dérivés méthyles en position α et β s'isomérisent sous l'influence d'un accepteur de protons, la double liaison se rapprochant du groupe sulfonyle. L'isomérisation de la benzylcrotylsulfone ne réussit pas dans les mêmes conditions.A moins qu'un substituant en position α n'encombre l'addition, les sulfones α‐oléfiniques qui résultent de l'isomérisation fixent des réactifs nucléophiles, ainsi que l'eau, l'alcool, le phénol et les mercaptannes en solution alcaline et la pipéridine.Le mécanisme des réactions d'isomérisation et d'addition est étudié et discuté en rapport avec les réactions analogues que présentent les sulfo

ISSN:0165-0513    

DOI:10.1002/recl.19510700502

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

Abstract3‐Homocholesterol (III), obtained by action of LiAlH4on cholesteryl‐3‐carboxylic methyl ester (II), which has been prepared from cholesteryl chloride by Grignard reaction, has the same steric configuration (β) at carbon atom 3 as cholesterol. Bromination of its acetate (IV) by means of bromosuccinimide, followed by elimination of HBr, leads to the acetate of 3‐homoprovitamin D3(Vα).This 3‐homoprovitamin D3(IX) can be synthesized with a far better yield by introducing first the double bond 7 and then the hydroxymethyl group 3. The magnesium derivative of 7‐dehydrocholesteryl chloride is transformed by CO2into the carboxylic acid (VII), which is readily methylated with diazomethane. Finally the 7‐dehydrocholesteryl‐3‐carboxylic methyl ester (VIII) is reduced with LiAlH4to 3‐homoprovitamin D3(IX).It is pointed out that the ultraviolet absorption characteristic for the conjugated system of double bonds 5‐7 is subjected to an infl

ISSN:0165-0513    

DOI:10.1002/recl.19510700503

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe dehydrogenation of hydrocarbons with the aid of chloranil (tetrachloro‐p‐benzoquinone) is investigated.According to the literature, thus far all hydrocarbons dehydrogenated by this quinone invariably have proved to contain a partially hydrogenated aromatic nucleus. It has been shown in the present study that those hydrocarbons which contain a —CH—CH— group adjacent to an aromatic nucleus or to a double bond may be dehydrogenated by chloranil (at about 140° C). On the other hand it is impossible to dehydrogenate perhydro‐aromatics and aliphatics under the same conditions.When aliphatic olefins and cyclopentene derivatives are treated with chloranil, consecutive reactions prohibit the isolation of initially dehydrogenated products.The reaction mechanism of the dehydrogenations is discussed. The experiments are in line with the view that the reaction involves a free radic

ISSN:0165-0513    

DOI:10.1002/recl.19510700504

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractAn approximate theoretical deduction is given for the viscosity coefficient of binary liquid mixtures combining a modified theory of Eyring for viscous flow with the statistical model due to Guggenheim for strictly regular solutions, using the Bragg‐Williams approximatio

ISSN:0165-0513    

DOI:10.1002/recl.19510700505

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19510700506

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractAnisic acid has been found to be a suitable reagent for the separation of Thorium from Uranium. From neutral solutions thorium may be freed from twice its quantity of uranium in a single precipitation and about eight times of uranium after a second precipitation.

ISSN:0165-0513    

DOI:10.1002/recl.19510700507

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe preparation of some N‐dialkylaminoalkyl derivatives of 1‐n‐propoxy‐2‐amino‐4‐nitrobenzene and 1‐methoxy‐3‐amino‐5‐nitrobenzene is described. The substances obtained were tested for (local) anaesthetic action with the aid of the rabbit cornea test, the frog muscle sciatic nerve tes

ISSN:0165-0513    

DOI:10.1002/recl.19510700508

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe investigation was carried out for the purpose of gaining an insight into the course of the decomposition of xanthogenates in acid aqueous medium.

ISSN:0165-0513    

DOI:10.1002/recl.19510700509

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractDihydroxyacetone (propanediolone) has been prepared from glycerol by the action ofAcetobacter suboxydansvar.biourgianum, nov. var. Kluyver and de Leeuw.It was found that the high values in the production of the ketose, obtained by several investigators, are not due to a hypothetical reducing impurity, present in the medium, but to erroneous data appearing in the literature concerning the reducing power of the dihydroxyacetone. Moreover, it was shown that during the conversion of the glycerol, some pyruvic acid and a fluorescing substance were formed. The latter displayed absorption bands at 273 mμand 450 m

ISSN:0165-0513    

DOI:10.1002/recl.19510700510

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19510700511

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY