PalBociclib Impurity 17

PalBociclib Impurity 14 Pyrido[2,3-d]pyriMidin-7(8H)-one, 8-cyclopentyl-5-Methyl-2-[[5-(1-piperazinyl)-2-pyridinyl]aMino]- Palbociclib Impurity 21 Palbociclib Impurity 12 PalBociclib Impurity 25

PalBociclib Impurity 18 Palbociclib-012 PalBociclib Impurity 23 2-chloro-4-(cyclopentylamino)-5-pyrimidinyl ethanone PalBociclib Impurity 11

Pyrido[2,3-d]pyriMidin-7(8H)-one, 2,6-dibroMo-8-cyclopentyl-5-Methyl- Palbociclib Impurity 2 Palbociclib Impurity 10 Palbociclib Impurity 15 PalBociclib Impurity 24

Palbociclib Impurity 20 PalBociclib Impurity 22 8-cyclopentyl-5-methyl-2-((5-(piperazin-1-yl)pyridin-2-yl)amino)-6-vinylpyrido[2,3-d]pyrimidin-7(8H)-one