CAS 851067-56-6: Pyrido[2,3-d]pyrimidin-7(8H)-one,6-bromo-8-cyclopentyl-5-methyl-2-[[5-(1-piperazinyl)-2-pyridinyl]amino]-

Palbociclib Impurity F is a high purity synthetic intermediate for the production of Palbociclib. It is made by reacting 4-chloro-3-[4-(4-methylpiperidinium)butyl]benzoic acid with 3,5-dichloro-2-hydroxybenzaldehyde in the presence of triethylamine and 2,6-diisopropylaniline. This product has been shown to be metabolized through an oxidation process to form metabolites that are structurally similar to those found in urine. The chemical structure of this impurity can be found in CAS No. 851067-56-6.