吡哌酸

8-Ethyl-2-{4-[3-(4-methoxy-3-methyl-phenyl)-3-oxo-propyl]-piperazin-1-yl}-5-oxo-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carboxylic acid ethyl ester

2-[4-(3,3-Dimethyl-2-oxo-butyl)-piperazin-1-yl]-8-ethyl-5-oxo-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carboxylic acid

8-Ethyl-5-oxo-2-[4-(2-oxo-2-thiophen-2-yl-ethyl)-piperazin-1-yl]-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carboxylic acid

8-Ethyl-5-oxo-2-[4-(2-oxo-2-pyridin-4-yl-ethyl)-piperazin-1-yl]-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carboxylic acid