Thieno(3,2-d)pyrimidine-2,4(1H,3H)-dione16233-51-5100 % similar 3H,4H-Thieno[3,2-d]pyrimidin-4-one16234-10-938 % similar Quinoxalinedione15804-19-032 % similar 2,3-Dihydroxyquinoxaline6287-20-332 % similar Thieno(2,3-d)pyrimidin-4(3H)-one14080-50-331 % similar