Synthesis and configuration of the cyclin-dependent kinase inhibitor roscovitine and its enantiomer

Abstract The cyclin-dependent kinase inhibitor ( R )-2-(6-benzylamino-9-isopropyl-9 H -purin-2-ylamino)butan-1-ol (roscovitine, 1a ), as well as its ( S )-enantiomer 1b , were synthesised. The chemical structure and absolute configuration of both enantiomers was confirmed by X-ray crystallography. Furthermore, high enantiomeric excess (>98%) was demonstrated by chiral chromatography of 1a and 1b , as well as NMR analysis of the diastereomeric Mosher's ester derivatives 2a and 2b .