8H-furo[2,3-b]indole-8-carboxylic acid, 3-cyano-3a-ethyl-2,3,3a,8a-tetrahydro-2-oxo-, methyl ester InChI=1/C15H14N2O4/c1-3-15-9-6-4-5-7-11(9)17(14(19)20-2)13(15)21-12(18)10(15)8-16/h4-7,10,13H,3H2,1-2H methyl 3-cyano-3a-ethyl-2-oxo-2,3,3a,8a-tetrahydro-8H-furo[2,3-b]indole-8-carboxylate