英文别名2-((6-Acetyl-8-cyclopentyl-5-methyl-7-oxo-7,8-dihydropyrido[2,3-d]pyrimidin-2-yl)amino)-5-(piperazin-1-yl)pyridine 1-oxide; Palbociclib Impurity R; Pyridine N-Oxide Palbociclib; Palbociclib Impurity 21; Palbociclib-12; Pyrido[2,3-d]pyrimidin-7(8H)-one, 6-acetyl-8-cyclopentyl-5-methyl-2-[[1-oxido-5-(1-piperazinyl)-2-pyridinyl]amino]- 
