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A Conformational Study of Cyclohexane‐1,3,5‐tricarbonitrile Derivatives
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A Conformational Study of Cyclohexane‐1,3,5‐tricarbonitrile Derivatives
作者:
Tsung‐Hsun Chuang,
Jim‐Min Fang,
期刊:
Journal of the Chinese Chemical Society
(WILEY Available online 2001)
卷期:
Volume 48,
issue 2
页码: 193-200
ISSN:0009-4536
年代: 2001
DOI:10.1002/jccs.200100032
出版商: WILEY‐VCH Verlag
关键词: Cyclohexane‐1,3,5‐tricarbonitrile;Kemp's triacid;Cyclohexane‐1,3,5‐trioxazoline;Alkylation
数据来源: WILEY
摘要:
AbstractCyclohexane‐1,3,5‐tricarbonitrile reached equilibrium having 1,3‐cis‐1,5‐cisand 1,3‐cis‐1,5‐trans isomers in a ratio of 3:7. Thecis, cis‐isomer preferred the conformation with three equatorial cyano groups, where as thecis, trans‐isomer displayed two cyano groups on equatorial positions and another cyano group on axial position. Condensation ofcis, cis‐cyclohexane‐1,3,5‐tricarbonitrile with L‐(S)‐valinol by the catalysis of ZnCl2in refluxing 1,2‐dichlorobenzene afforded two isomeric cyclohexane‐1,3,5‐trioxazolines in favor of the 1,3‐cis‐1,5‐trans isomer. Metalation ofcis, cis‐cyclohexane‐1,3,5‐tricarbonitrile, followed by alkylations with dimethyl sulfate, benzyl bromide or allyl bromide, gave the cor responding trialkylation products with predominance of 1,3‐cis‐1,5‐trans isomers. Thecis, trans‐isomer showed two cyano groups on axial positions and another cyano group on equatorial position, where as thecis, cis‐isomer exhibited three axial cyano groups. Treatment of trimethylcis, cis‐cyclohexane‐1,3,5‐tricarboxylate with lithium diisopropylamide and dimethyl sulfate afforded mainly the trimethyl ester of Kemp's triacid, which showed three axial carboxylate groups. Two competitive factors, i.e. the steric effect of in coming electrophiles and the dipole‐dipole inter actions of the cyano or carboxylate groups, might inter pla
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