Patent ID: 8058261

Claim:
A 3â€²-ethynylcytidine derivative represented by formula (1): wherein X represents a hydrogen atom, an alkylcarbonyl group of which alkyl moiety is a substituted or unsubstituted C1-C6 linear or branched alkyl group, or an alkoxycarbonyl group of which alkoxy moiety is a substituted or unsubstituted C1-C6 linear or branched alkoxy group; one of Y and Z represents a hydrogen atom or a group (R 1 )(R 2 )(R 3 )Si- and the other represents a group (R 4 )(R 5 )(R 6 )Siâ€”; and R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 , which may be identical to or different from one another, each represent a substituted or unsubstituted C1-C10 linear or branched alkyl group, a substituted or unsubstituted C3-C6 cycloalkyl group, or a substituted or unsubstituted C6-C14 aryl group, or a salt thereof.