Purine derivatives

摘要

A compound of formula (I), or a pharmaceutically acceptable salt thereof: (I) wherein X is hydrogen, amino, halogen, hydroxy, lower alkoxy or lower alkyl and R1 is wherein Y is methylene or a valence bond, R2 and R5 is H or lower, straight or branched alkyl, R3 is H or lower alkyl, or R2 and R3 can together form a cyclobutyl, cyclopentyl, cyclohexyl or phenyl ring, Z is oxygen, methylene, sulphur, sulphonyl or a valence bond, R4 is H, lower alkyl, aralkyl, a mono or bicyclic aromatic system optionally substituted with various groups. The compounds have been found useful for treating central nervous system ailments.