title: 3-[(Z)-(4-Diethyl-amino-6-oxocyclo-hexa-2,4-dien-1-yl-idene)methyl-amino]benzoic acid.
abstract: The title compound, C(18)H(20)N(2)O(3), crystallizes as the keto tautomer, unlike the vast majority of similar structures that have been reported that contain the hydr-oxy tautomer. There are two strong hydrogen bonds in the crystal structure, both accepted by the same carbonyl group: one intra-molecular N-H⋯O and one inter-molecular O-H⋯O. As a result, the carbonyl C=O distance is long, at 1.310 (2) Å, which may suggest the mol-ecule has a significant zwitterionic character. The dihedral angle between the benzene ring planes is 15.05 (7)°. As a result of the intramolecular hydrogen bond, the bridging C-C=N-C group is almost coplanar with the benzene ring that has the diethylamino substituent [dihedral angle 2.35 (15)°].
authors.forename: M T
authors.initials: MT
authors.lastname: Swamy
authors.forename: B
authors.initials: B
authors.lastname: Narayana
authors.forename: H S
authors.initials: HS
authors.lastname: Yathirajan
authors.forename: B K
authors.initials: BK
authors.lastname: Sarojini
authors.forename: Maciej
authors.initials: M
authors.lastname: Kubicki