2-(4-acetyl-1-piperazinyl)-8-benzyl-5,8-dihydro-5-oxopyrido [2,3-d]pyrimidine-6-carboxylic acid 、
2-(4-ethoxycarbonyl-piperazin-1-yl)-8-ethyl-5-oxo-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carboxylic acid 生成 8-benzyl-5,8-dihydro-2-(7-piperazinyl) -5-oxopyridio[2,3-d]pyrimidine-6-carboxylic acid 、
吡哌酸