To improve the stability and pharmacokinetic properties,prodrugs of L-ddG(L-2',3'-dideoxy-guanosine)and L-D4G (L-2',3'-dihydro-2',3'-dideoxyguanosine)modified with a series of substituted amino groups at C-6 position of the purine base were designed and synthesized and their anti-HIV activities were evaluated.Compounds 7d and 8g exhibited moderate activity and showed EC_(50)of 42μmol/L and 55μmol/L,respectively.