Crystal structure of ethyl 2-amino-4-(4-chlorophenyl)-4H-1-benzothieno[3,2-b]pyran-3-carboxylate

Abstract

The title compound, C20H16ClNO3S, is built up from three fused rings, one five- and two six-membered rings, linked to a 3-ethoxycarbonyl group and to a 4-chlorophenyl ring. The hydropyran ring has a flattened envelope conformation, with the C atom substituted by the 4-chlorophenyl ring as the flap (displaced by 0.077 (2) Å from the plane through the other atoms). The fused three-ring system is quasi-planar (r.m.s. deviation = 0.057 Å), with the largest deviation from the mean plane being 0.106 (1) Å for the C atom substituted by the 4-chlorophenyl ring. The 4-chlorophenyl ring is approximately perpendicular to the mean plane of the fused ring system, as indicated by the dihedral angle of 77.32 (6)° between their mean planes. There is an intramolecular N—H...O hydrogen bond forming an S(6) ring motif. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with an R22(12) ring motif. There are also short intermolecular Cl...O interactions present [3.1226 (12) Å] between neighbouring molecules.

Keywords

• crystal structure
• thioaurones
• thiophenones
• benzothienopyran
• N—H...O hydrogen bonds
• inversion dimers
• Cl...O short contact.