1-oxo-1,2-dihydroisoquinoline-3-carboxylic acid 3-isoquinolinecarboxylic acid, 1,2-dihydro-1-oxo- 7463-56-1 InChI=1/C6H4N4O2/c11-6(12)4-2-1-3-10-5(4)7-8-9-10/h1-3H,(H,11,12