Synthesis and cytotoxic activity of new isothiazolo[5,4-d]pyrimidine derivatives.

The synthesis of new 5-amino-3-methylisothiazolo[5,4-d]pyrimidines series is reported. The cytotoxic activity of these compounds has been determined on the two tumor cell lines (P-388 and KB). Two representative compounds 7 and 8 displayed a significant cytotoxic action. The results point a possible involvement of structural features in the inhibition effect against tumors.