4-Chloro-N'-(2-hy-droxy-4-meth-oxy-benzyl-idene)benzohydrazide methanol monosolvate

Crystal structure of 4-[(3-meth-oxy-2-oxidobenzyl-idene)azaniumyl]-benzoic acid methanol monosolvate

In the crystal of the title compound, C15H13NO4·CH3OH, the Schiff base mol-ecule exists in the zwitterionic form; an intra-molecular N-H⋯O hydrogen bond stabilizes the mol-ecular structure. The benzene rings are nearly co-planar, subtending a dihedral angle of 5.34 (2)°. In the crystal, classical O-H⋯O and weak C-H⋯O hydrogen bonds link the Schiff base mol-ecules and methanol solvent mol-ecules into a three-dimensional supra-molecular architecture. The crystal studied was refined as an inversion twin.

N′-(4-Diethylamino-2-hydroxybenzylidene)-4-methylbenzohydrazide

The title compound, C₁₉H₂₃N₃O₂, was prepared by condensing 4-diethyl­amino-2-hy­droxy­benzaldehyde and 4-methyl­benzo­hydrazide in methanol. The asymmetric unit contains two independent mol­ecules in which the two benzene rings make dihedral angles of 30.3 (3) and 18.9 (3)°. Intra­molecular O—H⋯N hydrogen bonds are observed in both mol­ecules. The crystal structure is stabilized by N—H⋯O hydrogen bonds, which form chains along the a axis.

2-Hydroxy-N′-(4-hydroxybenzylidene)-3-methylbenzohydrazide

The title compound, C₁₅H₁₄N₂O₃, was prepared by condensing 4-hy­droxy­benzaldehyde and 2-hy­droxy-3-methyl­benzo­hydra­zide in methanol. The two benzene rings make a dihedral angle of 19.03 (11)°. An intra­molecular O—H⋯O hydrogen bond is observed. The crystal structure is stabilized by inter­molecular O—H⋯O and N—H⋯O hydrogen bonds and C—H⋯O inter­actions, which lead to the formation of a three-dimensional network.

N′-(3-Ethoxy-2-hydroxybenzylidene)-2-hydroxy-3-methylbenzohydrazide

The title compound, C₁₇H₁₈N₂O₄, crystallizes with two independent mol­ecules in the asymmetric unit. The two benzene rings in each mol­ecule make dihedral angles of 7.6 (3) and 3.9 (3)°. Intra­molecular O—H⋯N and O—H⋯O hydrogen bonds are present in each mol­ecule. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into chains propagating in [010]. The are also a number of C—H⋯O and π–π inter­actions present [centroid–centroid distances = 3.874 (4) and 3.904 (3) Å], that result in the formation of a three-dimensional network.

N′-[(2-Hydroxynaphthalen-1-yl)methylidene]-4-nitrobenzohydrazide

In the title mol­ecule, C₁₈H₁₃N₃O₄, the hy­droxy group is involved in the formation of an intra­molecular O—H⋯N hydrogen bond. The dihedral angle between the planes of the benzene ring and the naphthyl ring system is 9.0 (2)°. In the crystal, mol­ecules are linked through N—H⋯O hydrogen bonds into chains along the c axis.