Patent ID: 8058424

Claim:
A method of preparing 5-azacytidine comprising the steps of: a) reacting 5-azacytosine with at least one silylating reagent in a dry organic solvent to yield a silylated 5-azacytosine having the structure: wherein each R 1 is an optionally substituted C 1 -C 20 alkyl group independently selected from the group consisting of straight chain alkyl groups, branched alkyl groups, and cyclic alkyl groups; b) contacting the reaction mixture of Step a) with trimethylsilyl trifluoromethanesulfonate and a compound having the structure; wherein each R 2 is an optionally substituted C 1 -C 20 acyl group independently selected from the group consisting of straight chain acyl groups, branched acyl groups, and benzoyl group, to yield a compound having the structure: c) contacting the reaction mixture of Step b) with an aqueous quenching composition and extracting the quenched reaction mixture; d) removing substantially all of the solvent in the extract of Step c); e) deprotecting the product in the extract of Step c) with sodium methoxide in methanol to yield 5-azacytidine; and f) recrystallizing the 5-azacytidine product of Step e) from a solvent system comprising dimethylsulfoxide.