作者:Alan R. Katritzky、Chandra Jayaram、Vassilatos N. Socrates
DOI:10.1016/s0040-4020(01)91920-9
日期:1983.1
1,3,5-Trimethylpyrazole and l-ethyl-3,5-dimethylpyrazole undergo lithiation exclusively at the α -position of the N-alkyl group. 1-Benzylpyrazole is metallated under kinetic control at -78° at the CH2 group, but the metallorganic intermediate rearranges rapidly at 23° to give the thermodynamically more stable 5-lithio-l-benzylpyrazole. 1-Methylpyrazole gives mixtures of α- and 5-lithiation; 1-ethylpyrazole
1,3,5-三甲基吡唑和1-乙基-3,5-二甲基吡唑仅在N-烷基的α-位进行锂化。1-苄基吡唑在-78°的CH 2基团的动力学控制下被金属化,但金属有机中间体在23°迅速重排,从而提供了热力学上更稳定的5-lithio-1-苄基吡唑。1-甲基吡唑产生α-和5-锂化的混合物;1-乙基吡唑仅显示5-锂化。碳负离子被各种亲电试剂捕获。