5H-[1]benzopyrano[4,3-b]pyridine-3-carboxylic acid, 2-methyl-5-oxo-, ethyl ester InChI=1/C16H13NO4/c1-3-20-15(18)11-8-12-14(17-9(11)2)10-6-4-5-7-13(10)21-16(12)19/h4-8H,3H2,1-2H ethyl 2-methyl-5-oxo-5H-chromeno[4,3-b]pyridine-3-carboxylate