(E)-4-Allyl-2-[(2-hydroxyphenyl)iminiomethyl]-6-methoxyphenolate

The title compound, C(17)H(17)NO(3), crystallizes in a zwitterionic form with cationic iminium and anionic enolate groups. The zwitterion exists in a trans configuration about the C=N bond. The dihedral angle between the two benzene rings is 13.42 (7)degrees. The methoxy group is almost coplanar [C-O-C-C = 2.1 (2)degrees] with the attached ring whereas the allyl unit is oriented at a dihedral angle of 67.9 (1)degrees. An intramolecular N-H center dot center dot center dot O hydrogen bond generates an S(6) ring motif. In the crystal, the molecules are linked into zigzag chains along [010] by O-H center dot center dot center dot O hydrogen bonds. In addition, weak C-H center dot center dot center dot pi interactions are observed.