2-[[tris(hydroxymethyl)methyl]aminomethylene]cyclohexa-3,5-dien-1(2H)-one and its 6-hydroxy and 6-methoxy derivatives.

The title compounds, 2-[[tris(hydroxymethyl)methyl]aminomethylene]cyclohexa-3,5-dien-1(2H)-one, C(11)H(15)NO(4), (I), 6-hydroxy-2-[[tris(hydroxymethyl)methyl]aminomethylene]cyclohexa-3,5-dien-1(2H)-one, C(11)H(15)NO(5), (II), and 6-methoxy-2-[[tris(hydroxymethyl)methyl]aminomethylene]cyclohexa-3,5-dien-1(2H)-one, C(12)H(17)NO(5), (III), adopt the keto-amine 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).