1,1-Dimethylethyl 4-(4-amino-3-pyridinyl)-1-piperazinecarboxylate is the impurity of Palbociclib (HY-50767). Palbociclib is an orally active selective CDK4 and CDK6 inhibitor with IC50 values of 11 and 16 nM, respectively[1].
References
[1] Fry DW, et al. Specific inhibition of cyclin-dependent kinase 4/6 by PD 0332991 and associated antitumor activity in human tumor xenografts. Mol Cancer Ther. 2004 Nov;3(11):1427-38. PMID:15542782