InChI=1/C16H14O3S/c1-9-8-10(2)20-16(15(18)19-3)13(9)11-6-4-5-7-12(11)14(16)17/h4-8H,1-3H indeno[2,1-b]thiopyran-9a(9H)-carboxylic acid, 2,4-dimethyl-9-oxo-, methyl ester methyl 2,4-dimethyl-9-oxoindeno[2,1-b]thiopyran-9a(9H)-carboxylate