8H-furo[2,3-b]indole-8-carboxylic acid, 3-cyano-3a-(1,1-dimethylethyl)-2,3,3a,8a-tetrahydro-2-oxo-, methyl ester InChI=1/C17H18N2O4/c1-16(2,3)17-10-7-5-6-8-12(10)19(15(21)22-4)14(17)23-13(20)11(17)9-18/h5-8,11,14H,1-4H methyl 3a-tert-butyl-3-cyano-2-oxo-2,3,3a,8a-tetrahydro-8H-furo[2,3-b]indole-8-carboxylate