| abstract |
There are disclosed s-triazolo[3,4-i]purine derivatives represented by formula: (see fig. I) wherein Y-Z represents (see fig II) or (see fig. III) where R4 represents hydrogen, alkyl, substituted or unsubstituted aromatic heterocyclic group or substituted or unsubstituted aryl; and X2 represents oxygen, sulfur or NH; each of R1 and R2 independently represents hydrogen, alkyl, cycloalkyl, aralkyl or substituted or unsubstituted aryl; R3 represents alkyl, cycloalkyl, aralkyl or substituted or unsubstituted aryl; X1 represents oxygen or sulfur; and ~ represents a single bond or a double bond or pharmaceutically acceptable salts thereof. |