Ethyl 4-hydr-oxy-9-tosyl-9H-carbazole-3-carboxyl-ate.

In the title compound, C(22)H(19)NO(5)S, the carbazole skeleton is nearly planar [maximum deviation = 0.043†(1)†à ] with the pyrrole ring oriented at dihedral angles of 2.32†(6) and 1.77†(6)° with respect to the adjacent benzene rings. The dihedral angle between the benzene ring of the tosyl group and the carbazole skeleton is 82.25†(5)°. Intra-molecular O-H⋯O hydrogen bonding results in the formation of a planar six-membered ring, which is oriented at a dihedral angle of 3.06†(4)° with respect to the adjacent carbazole skeleton. In the crystal structure, weak inter-molecular C-H⋯O inter-actions link the mol-ecules into infinite chains and π-π contacts between the benzene rings and between the pyrrole and benzene rings [centroid-centroid distances = 3.374†(1) and 3.730†(1)†à , respectively] may further stabilize the structure. A weak C-H⋯π inter-action is also present.