(3-Chlorophenyl){2-ethoxy-5-[(Z)-hydroxy(phenyl)methylidene]cyclopenta-1,3-dien-1-yl}methanone

Abstract

The title compound, C21H17ClO3, which crystallizes as one of two possible oxo/hydroxy-fulvene prototropic tautomers, possesses a strong intramolecular O—H...O hydrogen bond that closes a seven-membered ring. The dihedral angles between the central five-membered ring and two pendant rings are 55.05 (9) and 44.51 (10)°. The crystal packing is characterized by weak intermolecular C—H...O interactions between an H atom of the oxymethylene unit and the carbonyl group of an adjacent molecule, resulting in formation of chains of molecules along the a axis.