3-hydroxy-6-[(4-hydroxyphenylamino)methylene]cyclohexa-2,4-dienone and 2-hydroxy-6-[(4-hydroxyphenylamino)-methylene]cyclohexa-2,4-dienone

Abstract

The title compounds, both C13H11NO3, exist as the keto-amine tautomers, and the formal hydroxyl H atoms, which display strong intramolecular hydrogen bonds, are located on the N atoms. This is a verification of the preference for the keto-amine tautomeric form in the solid state. The 2-hydroxy isomer has two independent molecules, with the molecules linked by intramolecular N-H...O and O-H...O and intermolecular O-H...O hydrogen bonds into three-dimensional networks.