Patent ID: 8623912

Claim:
A compound of the following formula (I): wherein, R 1 is R 1 is not a phosphate group; R 2 , R 3 and R 4 are each independently selected from H, OH, OR 5 , NHR 6 and a lower alkyl group; W is O, O—CRjRj or NRj; G is P, S or C; X is SR 6 , OR 5 or NHRj; as G is S, X═NRj or ═O; Y is OR 5 , NHRj, CF 3 , an unsubstituted lower alkyl group or a lower alkyl group substituted by a hydroxyl group, a lower acyloxy group, a lower alkanoyl group, a lower alkoxyl group, an amino group, a halogen, a lower alkylamido group or a lower amido group; R 5 and R 6 are each independently H, Na, K, or an unsubstituted lower alkyl group or a lower alkyl group substituted by a hydroxyl group, a lower acyloxy group, a lower alkanoyl group, a lower alkoxyl group, an amino group, a halogen, a lower alkylamido group or a lower amido group; As G is C, X does not exist; Rn is O, NRj or S; Rj is H, OH, an alkyl group or a halogen.