1,3-Dimethyl-8-thiaxanthin 4,6-Dimethyl[1,2,5]thiadiazolo[3,4-d]pyrimidine-5,7(4H,6H)-dione 4712-49-6 NSC400016 [1,2,5]Thiadiazolo[3,4-d]pyrimidine-5,7(4H,6H)-dione, 4,6-dimethyl-