摘要:

AbstractLittle quantitative work has been published on the reactions of methylene with ethers.Doering et al1W. E. Doering, L. H. Knox, andM. Jones, J. Org. Chem.24, 137 (1959)studied the reaction of methylene with diethyl ether and found ethyl propyl ether and ethyl isopropyl ether with relative yields 55.5 : 45.5. This implies that the methylene inserts 1.2 times as rapidly in the secondary C‐H bonds as in the primary C‐H bonds. They found no evidence for any carbon rearrangement of a diethyl ether‐methylene ylid but indicated that a hydrogen rearrangement from such an “ylid” would lead to deviations from statistical attack in the required direction.FranzenandFikentscherV. Franzen, andL. Fikentscher, Annalen617,1, (1958).were able to show, directly, by the use of labelled compounds that none of the insertion products arose by a carbon skeleton rearrangement. They also showed that in the reaction of methylene with diethyl ether some methyl ethyl ether is formed but no quantitative data was

ISSN:0165-0513    

DOI:10.1002/recl.19640830202

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe synthesis of tetraalkoxy‐ and chloroalkoxygermanes is described. The method employed consists of the treatment of tetrachlorogermane with trialkyl orthoformate

ISSN:0165-0513    

DOI:10.1002/recl.19640830203

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractSix new substituted aminoethyl esters of hydroxydiphenylborane are described.In contrast to the behaviour of triptych boroxazolidines, in which subsituents in the amino‐alcohol carbon atoms are associated with increased resistance of the boroxazolidine towards acidic hydrolysis, increased substitution among the monocyclic boroxazolidines is associated with increased lability in acidic solution

ISSN:0165-0513    

DOI:10.1002/recl.19640830204

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractA description is given of a thermoelectric vapour phase osmometer for the determination of molecular weights or, more generally, of the osmotic activity of solutions. In this instrument the vapour pressure difference between a solution of the substance under investigation and the pure solvent is converted into a temperature difference between the junctions of one or more thermocouples. From a detailed consideration of the heat and mass transfer in the steady state, the temperature difference can be calculated. The theory is fully corroborated by some experiments on solutions in benzene and water of substances of known molecular weights. Finally, an application of the method to the determination of the molecular weights of some polystyrene samples, ranging between 3 000 and 14000, is discussed. The upper limit lies around 30 000 with an accuracy of about 10%.

ISSN:0165-0513    

DOI:10.1002/recl.19640830205

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe simultaneous use of two solvent systems allows of an easy chromatographical identification of yohimbine and a number of related alkaloids in extracts from several yohimbine‐containing barks. By using these solvent systems the occurrence of two unknown alkaloids was demonstrate

ISSN:0165-0513    

DOI:10.1002/recl.19640830206

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractUsing column chromatography a new alkaloid has been isolated from several barks containing yohimbine.

ISSN:0165-0513    

DOI:10.1002/recl.19640830207

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe structure has been determined of a new alkaloid isolated from barks ofPausinystalia yohimbe. The compound is tetrahydro‐desmethyl‐corynantheine. Stereochemically it can be related to tetrahydro‐desmethoxy‐corynantheine alcohol, a compound described earlier byKarre

ISSN:0165-0513    

DOI:10.1002/recl.19640830208

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe kinetics of the hydrolysis of furan and 2,5‐dimethylfuran in aqueous perchloric acid solution at 25° have been investigated by spectroscopic and vapour pressure methods. The logarithm of the first order rate constant is linear inHammett'sacidity function, H0. The solvent deuterium isotope effect, kH/kD, of the hydrolysis of 2,5‐dimethylfuran amounts to 1.7.A mechanism is proposed in which the first step is a slow proton transfer to the α‐carbon atom of the fur

ISSN:0165-0513    

DOI:10.1002/recl.19640830209

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractA series of hydrazine derivatives of 2‐, 3‐ and 4‐pyridylacetic acids has been prepared by catalytic hydrogenation of aldehyde or ketone pyridylacetyl‐hydrazones and testedin vitrofor MAO inhibition. Compounds derived from benzylhydrazine were the most active MAO inhibitorsi

ISSN:0165-0513    

DOI:10.1002/recl.19640830210

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19640830211

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY