摘要:

AbstractThe relative energies of the pseudorotation conformations oftrans‐1,2‐dihalogenocyclopentanes are evaluated excluding dipole‐dipole interactions. The most stable form corresponds to the half‐chair model with the halogen atoms diaxally disposed about the “puckered” carbon

ISSN:0165-0513    

DOI:10.1002/recl.19660851002

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThe dipole moments and NMR spectra oftrans‐1,2‐dichloro‐ (I),trans‐1,2‐bromochloro‐ (II),trans‐1,2‐dibromo‐ (III) andtrans‐1,2‐dibromo‐1‐methylcyclopentane (IV) in several solvents are reported. Special attention is given to the separation of the outer peaks in the low‐field part of the NMR spectra, due to the protons in the CHX‐moiety. This separation is equal to JAX+ JBXand is shown to be correlated linearly with the square of the electric moment.It is proposed that the conformational properties of these molecules be described in terms of a solvent‐dependent dynamic equilibriumaa⇌ee, with the diaxial conformation predominating even in a highly polar solvent. Each of the two conformers may correspond to the half‐chair or the envelope model with the halogen atoms in the most puckered part of the ring. A limited pseudoli

ISSN:0165-0513    

DOI:10.1002/recl.19660851003

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThe infrared and Raman spectra oftrans‐1,2‐dichloro‐(I),trans‐1‐bromo‐2‐chloro(II),trans‐1,2‐dibromo‐(III) andtrans‐1,2‐dibromo‐1‐methylcyclo‐pentane(IV) were measured in carbon disulfide and in the neat liquid. From the properties of the bands assigned to the carbon‐halogen stretching frequencies it is concluded that the diaxial conformations predominate in solution, the halogen atoms occupying the most buckled part of the ring. The absorption bands of I are broader than those of III and IV. This seems to indicate that the ring geometry of I is less defined and that in compound I twisting of the ring in a pseudolibration movement occurs to a larger extent. From a comparison with the carbon‐halogen stretching frequencies in the analogous cyclohexan

ISSN:0165-0513    

DOI:10.1002/recl.19660851004

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThe polymerization of ethylene withZiegler‐type catalysts containing mono‐and bis‐cyclopentadienylvanadium compounds as constituents has been studied. The activities of these catalyst mixtures have been compared with those of two known highly active systems,viz.(i) the one based on biscyclopentadienyltitanium dichloride and aluminium alkyls and (ii) the one based on vanadium tetrachloride or vanadium oxytrichloride, respectively, and a large excess of aluminium alkyls. Under a wide variety of reaction conditions the cyclopentadienylvanadium compounds were found to be less active. Moreover, with vanadium, moderate activity was observed for systems based on monocyclopentadienyl derivatives and negligible to weak activity for mixtures based on biscyclopentadienyl derivatives. The large difference in suitability as catalyst constituents between the biscyclopentadienyl derivatives of titanium and of vanadium is disc

ISSN:0165-0513    

DOI:10.1002/recl.19660851005

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractExperiments are described aiming at a simplification of the catalyst system originally consisting of a mixture of tetraphenyltin, aluminium bromide and vanadium tetrachloride (or vanadium oxytrichloride). It is shown that tetraphenyltin merely acts as a phenylating agent for the aluminium bromide and that only two of the four phenyl groups are available for this purpose. With regard to catalytic activity the original mixture is equivalent to mixtures of vanadium tetrachloride and excess ofmonoalkyl‐ ormonoaryl‐aluminium halides. Some evidence has been obtained that organic groups are part of the vanadium/aluminium complex occurring in the reaction mixtu

ISSN:0165-0513    

DOI:10.1002/recl.19660851006

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractSpectrophotometric measurements in the visible region on soluble catalyst systems prepared from (i) vanadium tetrachloride, aluminium bromide and tetraphenyltin and (ii) vanadium tetrachloride or vanadium oxytrichloride and ethylaluminium dihalides are reported. The formation of hydrocarbon‐soluble inorganic vanadium/aluminium halide complexes containing the transition metal in the tetra‐, tri‐ and di‐valent oxidation state is described and their absorption spectra are recorded. By means of these spectra it is shown that all catalyst systems contain analogous vanadium species,viz.complexes of divalent vanadium in which the transition metal is surrounded octahedrally by halogen atoms only. Evidence is given for the view that organic groups are attached to the aluminium site of the complexes. The structure of the catalytically active species in these systems is di

ISSN:0165-0513    

DOI:10.1002/recl.19660851007

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractSome derivatives ofd‐methylamphetamine anddl‐amphetamine obtained by reaction of these amines with l‐glutamic acid anhydride and 1‐adamantanecarbonyl chloride are de

ISSN:0165-0513    

DOI:10.1002/recl.19660851008

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractWhen thiophene is alkylated with 1‐bromoadamantane a separable mixture of 2‐(1‐adamantyl)thiophene and 3‐(1‐adamantyl)thiophene is formed. Using 2‐bromoadamantane a similar mixture of 2‐(2‐adamantyl)thiophene and 3‐(2‐adamantyl)thiophene is formed. Desulfurization furnished the correspondin

ISSN:0165-0513    

DOI:10.1002/recl.19660851009

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

Abstract2‐(1‐Adamantyl)thiophene can be easily carboxylated, formylated, acylated and nitrated, giving 2,5‐disubstituted thiophenes. Desulfurization furnishes the corresponding (1‐adamantyl)alkanes with a functional group at the ω‐c

ISSN:0165-0513    

DOI:10.1002/recl.19660851010

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY

摘要:

AbstractThree β‐diazosulfones are obtained by alkaline fission ofN‐(2‐arylsulfonylethyl)‐N‐nitrosourethanes. Alternative approaches,i.e.oxidation of phenylsulfonylacetone hydrazone and alkaline decomposition of the corresponding tosylhydrazone, did n

ISSN:0165-0513    

DOI:10.1002/recl.19660851011

出版商:WILEY‐VCH Verlag    

年代:1966

数据来源: WILEY