英文别名1-Piperazinecarboxylic acid, 4-[6-[[5-bromo-4-(cyclopentylamino)-2-pyrimidinyl]amino]-3-pyridinyl]-, 1,1-dimethylethyl ester; Palbociclib Impurity 122; Palbociclib Impurity 171; 2-Methyl-2-propanyl 4-(6-{[5-bromo-4-(cyclopentylamino)-2-pyrimidinyl]amino}-3-pyridinyl)-1-piperazinecarboxylate