Intermediate and process for preparing the beta-anomer of gemcitabine hydrochloride via a low temperature stereoselective glycosylation reaction

摘要

Disclosed is a gemcitabine precursor compound of formula (I) wherein P is hydrogen or a hydroxyprotective group. Also disclosed is a process for the preparation of the above precursor compound of formula (I), which comprises reacting a lactol compound of formula (IV), wherein P is as defined hereinbefore with trichloroacetonitrile in an inert organic solvent and in the presence of a base. Further disclosed is the use of the compound of formula (I) in a stereoselective glycosylation process for the preparation of greater than 99% beta-anomer enriched gemcitabine hydrochloride.