反应详情

84.6 g. of 1-methyl-4-carboethoxy-5-aminopyrazole and 74.1 g. of orthoformic acid triethyul ester are heated together until the splitting off of ethanol has ended. The oily residue is distilled under oil pump vacuum to obtain 5-[(ethoxy-methylene)amino]-1-methyl-1h-pyrazole-4-carboxylic acid, ethyl ester b.p. 98°-102°; m.p. 32°-34° (yield87%).

1. distillationThe oily residue is distilled under oil pump vacuum