2-[(E)-(4-Chlorophenyl)methyleneamino]-N-(X-methylphenyl)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide, where X = 2 and 3.

The title compounds, both C(23)H(21)ClN(2)OS, are isomeric, with (I) and (II) being the N-3-methylphenyl and N-2-methylphenyl derivatives, respectively. The dihedral angle between the 4-chlorophenyl group and the thiophene ring in (II) [38.1 (1) degrees ] is larger than that in (I) [7.1 (1) degrees ], indicating steric repulsion between the chlorophenyl and o-toluidine groups in (II). In both compounds, an intramolecular N-H...N hydrogen bond forms a pseudo-six-membered ring, thus locking the molecular conformation. In the crystal structures, molecules are connected via N-H...O hydrogen bonds, forming chains along the b axis in (I) and along the c axis in (II). Intermolecular C-H...O/S and pi-pi interactions are also observed in (II), but not in (I).