Experimental

R factor = 0.044; wR factor = 0.138; data-to-parameter ratio = 13.1. In the title molecule, C19H17N3O6, the indole ring system is essentially planar (r.m.s. deviation = 0.009 Å) and forms a dihedral angle of 31.96 (9) with the nitro-substituted benzene ring. In the crystal, molecules are linked by pairs of N—H O hydrogen bonds, forming inversion dimers which are connected by further N—H O hydrogen bonds into a two-dimensional network parallel to (102). Related literature For background to and potential applications of the titl