4-Methyl-7,8,9,10-tetra-hydro-cyclo-hepta-[b]indol-6(5H)-one.

In the title compound, C(14)H(15)NO, the seven-membered ring exhibits a slightly distorted twist-boat conformation. The pyrrole ring forms a dihedral angle of 1.44 (10)° with the fused benzene ring. N-H⋯O hydrogen bonds form a centrosymmetric dimer and weak C-H⋯π inter-actions are also found in the crystal structure.

4,8-Dimethyl-pyrano[2,3-a]carbazol-2(11H)-one.

The mol-ecule of the title compound, C(17)H(13)NO(2), is nearly planar, the r.m.s. deviation for all non-H atoms excluding the two methyl C atoms being 0.089 Å. Inter-molecular N-H⋯O and C-H⋯O hydrogen bonds are found in the crystal structure. C-H⋯π inter-actions are also found. The H atoms of the methyl group attached to the benzene ring are disordered equally over two positions.

3-Methyl-3,4-dihydro-9H-carbazol-1(2H)-one.

In the title mol-ecule, C(13)H(13)NO, the dihedral angle between the benzene ring and the fused pyrrole ring is 2.03 (5)°. The methyl group at the 3-position has an equatorial orientation. The cyclo-hexene ring adopts an envelope conformation. Three C atoms of the cyclo-hexene ring, with their attached H atoms, and all atoms of the methyl group are disordered over two positions, the site-occupancy factors being 0.883 (2) and 0.117 (2). In the crystal structure, mol-ecules are stabilized by inter-molecular N-H⋯O hydrogen bonds. A C-H⋯π inter-action, involving the benzene ring, is also found.