3,5-Dihydroxy-N′-(2-hydroxybenzylidene)benzohydrazide monohydrate

The title potential antibacterial compound, C14H12N2O4·H2O, is a Schiff base which has an intramolecular O—H⋯N hydrogen bond and crystallizes with one uncoordinated water molecule, which links three symmetry-related molecules through two O—H⋯O and one N—H⋯O hydrogen bond. In the crystal structure, further intermolecular O—H⋯O hydrogen bonds link symmetry-related molecules, forming layers parallel to the bc plane.

The title potential antibacterial compound, C 14 H 12 N 2 O 4 ÁH 2 O, is a Schiff base which has an intramolecular O-HÁ Á ÁN hydrogen bond and crystallizes with one uncoordinated water molecule, which links three symmetry-related molecules through two O-HÁ Á ÁO and one N-HÁ Á ÁO hydrogen bond. In the crystal structure, further intermolecular O-HÁ Á ÁO hydrogen bonds link symmetry-related molecules, forming layers parallel to the bc plane.

Comment
Compounds derived from the Schiff base condensation reaction of aldehydes with hydrazides have been widely investigated both from a structural point of view and for their biological activity (Jing et al., 2006;Yang, 2007;Wang et al., 2007).
The molecular structure of the title compound ( Fig. 1) is a Schiff base, which has an intramolecular O1-H1···N1 hydrogen bond (Table 1), and crystallizes as a water solvate. In the crystal structure the water molecule links three symmetry related molecules through two donnor O-H···O hydrogen bonds and one acceptor N-H···O hydrogen bond (Table 1).
Together with two further intermolecular O-H···O hydrogen bonds, layers parallel to the bc plane are formed (Fig. 2).

Experimental
Salicylaldehyde and 3,5-dihydroxybenzoic acid hydrazide were purchased from Aldrich and were used without further purification. Salicylaldehyde (0.1 mmol, 12.2 mg) and 3,5-dihydroxybenzoic acid hydrazide (0.1 mmol, 16.8 mg) were mixed in a methanol solution (10 cm 3 ). The mixture was stirred at reflux for 30 min and cooled to room temperature. After keeping the solution in air for a few days, yellow block-shaped crystals appeard at the bottom of the vessel.