英文别名4-[6-[(8-Cyclopentyl-5-methyl-7-oxo-7,8-dihydropyrido[2,3-d]pyrimidin-2-yl)amino]pyridin-3-yl]piperazine-1-carboxylic acid tert-butyl ester; Palbociclib Impurity X; 1-Piperazinecarboxylic acid, 4-[6-[(8-cyclopentyl-7,8-dihydro-5-methyl-7-oxopyrido[2,3-d]pyrimidin-2-yl)amino]-3-pyridinyl]-, 1,1-dimethylethyl ester; 6-Desacetyl-N-Boc Palbociclib; Palbociclib Impurity 97