英文别名Palbociclib Impurity 50; 4-[6-[(8-Cyclopentyl-6-ethenyl-7,8-dihydro-5-methyl-7-oxopyrido[2,3-d]pyrimidin-2-yl)amino]-3-pyridinyl]-1-piperazinecarboxylic acid 1,1-dimethylethyl ester; Palbociclib Impurity V; 1,1-Dimethylethyl 4-[6-[(8-cyclopentyl-6-ethenyl-7,8-dihydro-5-methyl-7-oxopyrido[2,3-d]pyrimidin-2-yl)amino]-3-pyridinyl]-1-piperazinecarboxylate; tert-butyl 4-[6-[(8-cyclopentyl-5-methyl-7-oxo-6-vinyl-pyrido[2,3-d]pyrimidin-2-yl)amino]-3-pyridyl]piperazine-1-carboxylate; tert-butyl 4-[6-[(8-cyclopentyl-6-ethenyl-5-methyl-7-oxopyrido[2,3-d]pyrimidin-2-yl)amino]pyridin-3-yl]piperazine-1-carboxylate 
