A practical synthesis of the major 3-hydroxy-2-pyrrolidinone metabolite of a potent CDK2/cyclin A inhibitor.

The synthesis of the major metabolite of a potent 3-aminopyrazole CDK2/cyclin A inhibitor is presented. A stereoconservative approach starting from malic acid was employed to construct the hydroxy-substituted pyrrolidinone moiety. In the key step of the synthesis the use of cyanoborohydride immobilized on Amberlyst 26 in trifluoroethanol represented a valid alternative to conventional solution-phase reducing agents.