2H,8H-Benzo(1,2-b:5,4-b')dipyran-3-carboxylic acid, 10-methyl-2-oxo-, ethyl ester 93670-09-8 Ethyl 10-methyl-2-oxo-2H,8H-benzo(1,2-b:5,4-b')dipyran-3-carboxylate