Ethyl 4-hydroxy-9-tosyl-9H-carbazole-3-carboxylate

Abstract

In the title compound, C22H19NO5S, the carbazole skeleton is nearly planar [maximum deviation = 0.043 (1) angstrom] with the pyrrole ring oriented at dihedral angles of 2.32 (6) and 1.77 (6)degrees 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)degrees. Intramolecular O-H center dot center dot center dot O hydrogen bonding results in the formation of a planar six-membered ring, which is oriented at a dihedral angle of 3.06 (4)degrees with respect to the adjacent carbazole skeleton. In the crystal structure, weak intermolecular C-H center dot center dot center dot O interactions link the molecules into infinite chains and pi-pi contacts between the benzene rings and between the pyrrole and benzene rings [centroid-centroid distances = 3.374 (1) and 3.730 (1) A, respectively] may further stabilize the structure. A weak C-H center dot center dot center dot pi interaction is also present.