Method for purifying protected 2'-deoxycytidines

摘要

A protected 2'-deoxycytidine is purified by precipitating the protected 2'-deoxycytidine represented by general formula (3) in the form of a hydrated crystal from a solution containing the protected 2'-deoxycytidine and water, and by recovering the protected 2'-deoxycytidine: wherein R1 represents a 4-methoxytrityl, 4, 4'-dimethoxytrityl, or triphenylmethyl group; and B1 represents a cytosine group having a protected amino group. The compound represented by general formula (3) may be, in particular, a protected 2'-deoxycytidine represented by formula (4): The 2'-deoxycytidine is used as a raw material for antisense DNA.