摘要
用MINDO/3方法研究了N-取代乙基吡唑热消除反应H_3C_3N_2CH_2CH_2XH_4C_3N_2+H_2C=CHX(反应Ⅰ～Ⅲ,对应X=H,CH_3,F)的机理,结果表明,甲基的超共轭效应以及F的强吸电子作用和邻基参与使得反应Ⅱ和反应Ⅲ的活化势垒降低,比反应Ⅰ更易进行。
MINDO/ 3 SCF calculations have been carried out to study the thermal elimination of N-substituted ethyl pyrazole;A concerted reaction involving a five membered ring transition state(TS) was found. The results obtained show that there is a weak influence on the reactivity by the substituents on ft carbon of the ethyl group. The hyperconjugation of the methyl group, and the strong electronegativity and the weak conjugation of the fluorine atom stabilize the corresponding TS respectively, the activation barriers of these two reactions are lower than that of the non-substituted reactent.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1991年第9期1212-1215,共4页
Chemical Journal of Chinese Universities
基金
国家教委访问学者基金
关键词
吡唑
N-取代乙基
热消除反应
Thermal elimination, Transition state, Intrinsic reaction coordinate
