The cis-trans Isomerisation of Homologous 2-Hydroxycycloalkanecarboxylic Acids under Basic Conditions  

作　　者：GYARMATI Cs. Zsuzsanna PALINKO lstván BOKROS Attila MARTINEK A. Tamás BERNATH Gábor 

机构地区：[1]Institute of Pharmaceutical Chemistry, University ofSzeged, Szeged POB 121, H-6701 Hungary [2]Research Group for Heterocyclic Chemistry of the Hungarian Academy of Sciences and University of Szeged, Szeged POB 121, H-6701 Hungary [3]Department of Organic Chemistry, University of Szeged, Szeged, Ddm tér 8, H.6720 Hungary

出　　处：《Chinese Journal of Chemistry》2006年第12期1792-1795,共4页中国化学（英文版）

摘　　要：The cis→trans isomerisation of homologous 2-hydroxycycloalkanecarboxylic acids in strongly basic aqueous solution was studied starting from the cis isomers. It was found that the cyclopentane, cyclohexane and cycloheptane homologues afforded synthetically useful amounts of the trans acids and the procedure resulted in relatively small quantities of the corresponding olefinic acids. In contrast, the isomerisation of the cis-2-hydroxycyclooctanecarboxylic acid produced roughly equal amounts of the cis and trans isomers and the 1-cyclooctenecarboxylic acid at equilibrium. Molecular modelling with the PM3 semiempirical method of the reactants, products and the intermediates applying explicit water molecules as reaction medium gave a fair estimate for the rate sequence of the idealised （dehydration-free） isomerisation reactions in aqueous base solution.The cis→trans isomerisation of homologous 2-hydroxycycloalkanecarboxylic acids in strongly basic aqueous solution was studied starting from the cis isomers. It was found that the cyclopentane, cyclohexane and cycloheptane homologues afforded synthetically useful amounts of the trans acids and the procedure resulted in relatively small quantities of the corresponding olefinic acids. In contrast, the isomerisation of the cis-2-hydroxycyclooctanecarboxylic acid produced roughly equal amounts of the cis and trans isomers and the 1-cyclooctenecarboxylic acid at equilibrium. Molecular modelling with the PM3 semiempirical method of the reactants, products and the intermediates applying explicit water molecules as reaction medium gave a fair estimate for the rate sequence of the idealised （dehydration-free） isomerisation reactions in aqueous base solution.

关 键 词：geometric isomerisation base catalysis reaction mechanism molecular modelling 

分 类 号：O624.5[理学—有机化学]