1H-indene-1,3(2H)-dione, 2,2-dimethoxy- 2,2-dimethoxy-1H-indene-1,3(2H)-dione InChI=1/C11H10O4/c1-14-11(15-2)9(12)7-5-3-4-6-8(7)10(11)13/h3-6H,1-2H