2-Bromo-4-chloro-6-(cyclo-pentyl-imino-meth-yl)phenol

N′-(5-Chloro-2-hydroxybenzylidene)-2-methoxybenzohydrazide

The title Schiff base compound, C₁₅H₁₃ClN₂O₃, was prepared by the reaction of equimolar quanti­ties of 5-chloro-2-hy­droxy­benzaldehyde with 2-meth­oxy­benzohydrazide in a methanol solution. The dihedral angle between the two benzene rings is 20.6 (3)°. An intra­molecular O—H⋯N hydrogen bond may influence the mol­ecular conformation. In the crystal structure, mol­ecules form chains along the b direction via inter­molecular N—H⋯O hydrogen bonds which are bifurcated involving an intra­molecular N—H⋯O hydrogen bond.

N'-[(2-Hydr-oxy-1-naphth-yl)methyl-idene]-2-nitro-benzohydrazide

In the title Schiff base compound, C₁₈H₁₃N₃O₄, prepared by the reaction of 2-hydr­oxy-1-naphthaldehyde with 2-nitro­benzohydrazide, the dihedral angle between the benzene ring and naphthyl ring system is 23.0 (2)°. There is an intra­molecular O—H⋯N hydrogen bond involving the naphthalene hydr­oxy substituent and a hydrazide N atom. In the crystal structure, symmetry-related mol­ecules are linked through inter­molecular N—H⋯O hydrogen bonds, forming chains propagating in [101].

(E)-2-[(2-Ethyl-phen-yl)iminiometh-yl]-6-hydroxy-phenolate

The mol-ecule of the title compound, C(15)H(15)NO(2), crystallizes in a zwitterionic form, and displays an E configuration about the C=N bond. The dihedral angle between the two aromatic rings is 5.59 (6)°. An intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal structure, pairs of mol-ecules are linked into centrosymmetric R(2) (2)(10) dimers by pairs of O-H⋯O hydrogen bonds. Aromatic π-π inter-actions are observed between the benzene rings of adjacent dimers [centroid-centroid distance = 3.4808 (7) Å].

2-(Hydrazonomethyl)phenol

The conformation of the title compound, C₇H₈N₂O, is stabilized by an intra­molecular O—H⋯N hydrogen bond. The crystal structure shows inter­molecular N—H⋯O hydrogen bonds.