4H-1-benzopyran-3-carboxylic acid, 2-methyl-4-oxo-, ethyl ester InChI=1/C13H12O4/c1-3-16-13(15)11-8(2)17-10-7-5-4-6-9(10)12(11)14/h4-7H,3H2,1-2H ethyl 2-methyl-4-oxo-4H-chromene-3-carboxylate