2',4,6-trimethoxy-6'-methyl-3H,4'H-spiro[1-benzofuran-2,1'-cyclohex[2]ene]-3,4'-dione InChI=1/C17H18O6/c1-9-5-10(18)6-14(22-4)17(9)16(19)15-12(21-3)7-11(20-2)8-13(15)23-17/h6-9H,5H2,1-4H spiro[benzofuran-2(3H),1'-cyclohex[2]ene]-3,4'-dione, 2',4,6-trimethoxy-6'-methyl-