1H-indole-2-carboxylic acid, 2,3,3a,6,7,7a-hexahydro-3a-hydroxy-6-oxo- 3a-hydroxy-6-oxo-2,3,3a,6,7,7a-hexahydro-1H-indole-2-carboxylic acid InChI=1/C9H11NO4/c11-5-1-2-9(14)4-6(8(12)13)10-7(9)3-5/h1-2,6-7,10,14H,3-4H2,(H,12,13