2-{[Tris(hydroxymethyl)methyl]amino-methylene}cyclohexa-3,5-dien-1(2H)-one and its 6-hydroxy and 6-methoxy derivatives

Abstract

The title compounds, 2-{[tris(hydroxymethyl)methyl]aminomethylene}cyclohexa-3,5-dien-1(2H)-one, C11H15NO4, (I), 6-hydroxy-2-{[tris (hydroxymethyl)methyl] aminomethylene}-cyclohexa-3,5-dien-1(2H)-one, C11H15NO5, (II), and 6-methoxy-2-{[tris(hydroxymethyl)methyl] aminomethylene}cyclohexa-3,5-dien-1(2H)-one, C12H17NO5, (III), adopt the ketoamine tautomeric form, with the formal hydroxy H atom located on the N atom, and the NH group and oxo O atom display a strong intramolecular N-H...O hydrogen bond. The N-H...O hydrogen-bonded rings are almost planar and coupled with the cyclohexadiene rings. The carbonyl O atoms accept two other H atoms from the alcohol groups of adjacent molecules in (I), and one from the alcohol and one from the phenol group in (II), but from only one alcohol H atom in (III).