METHOD OF PRODUCING 2' -DEOXY-5-AZACYTIDINE (DECITABINE)

Summary Method of producing 2'-deoxy-5-azacytidine (Decitabine) by providing a compound of formula (I): wherein R is a removable substituent known per se; and R 1 is a glycoside donor preferably a 1-halogen derivative, an imidate preferably the trichloromethyl derivative, or a thio-alkyl derivative; further providing a silylated base of formula (II): wherein R 2 is a protecting group, preferably a trimethylsilyl TMS)-residue; reacting the compound of formula (I) and the compound of formula (II) together in a suitable anhydrous solvent and in the presence of a suitable catalyst; and removing the substituents R from the compound obtained in order to obtain the compound 2'-deoxy-5-azacytidine (Decitabine), characterized in that said catalyst is selected from the group comprising a salt of an aliphatic sulphonic acid and/or the salt of a optionally substituted aromatic sulphonic acid.