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.