2H-[1]benzopyrano[2,3-d]pyrimidine-2,4(3H)-dione, 9-methoxy- 9-methoxy-2H-chromeno[2,3-d]pyrimidine-2,4(3H)-dione InChI=1/C12H8N2O4/c1-17-8-4-2-3-6-5-7-10(15)13-12(16)14-11(7)18-9(6)8/h2-5H,1H3,(H,13,15,16