N'-(3-Eth-oxy-2-hydroxy-benzyl-idene)-4-hydr-oxy-3-methoxy-benzohydrazide monohydrate.

In the title compound, C(17)H(18)N(2)O(5)·H(2)O, the dihedral angle between the two aromatic rings is 7.86 (7)° and an intra-molecular O-H⋯N hydrogen bond is observed. In the crystal structure, mol-ecules are linked into a three-dimensional network by inter-molecular O-H⋯O and N-H⋯O hydrogen bonds.

N'-(4-Hydr-oxy-3-methoxy-benzyl-idene)-4-methoxy-benzohydrazide monohydrate.

In the title compound, C(16)H(16)N(2)O(4)·H(2)O, the dihedral angle between the two aromatic rings is 19.6 (2)°. In the crystal structure, mol-ecules are linked into a three-dimensional network by inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds.

N'-(5-Bromo-2-hydr-oxy-3-methoxy-benzyl-idene)-4-hydr-oxy-3-methoxy-benzohydrazide dihydrate.

In the title compound, C(16)H(15)BrN(2)O(5)·2H(2)O, the dihedral angle between the two aromatic rings is 2.9 (2)° and an intra-molecular O-H⋯N hydrogen bond is observed. One of the water mol-ecule is disordered over two positions, with occupancies of 0.

2-Meth-oxy-N'-(2-methoxy-benzyl-idene)benzohydrazide.

The title Schiff base compound, C(16)H(16)N(2)O(3), was derived from the condensation of 2-methoxy-benzaldehyde with 2-methoxy-benzohydrazide in an ethanol solution. The dihedral angle between the two aromatic rings is 87.5 (3)°.

4-Chloro-N'-(2-hydroxy-benzyl-idene)benzohydrazide monohydrate.

The asymmetric unit of the title compound, C(14)H(11)ClN(2)O(2)·H(2)O, contains a Schiff base mol-ecule and a water mol-ecule of crystallization. The dihedral angle between the two aromatic rings is 27.3 (4)°.

N'-(2-Hydroxy-benzyl-idene)-2-methoxy-benzohydrazide monohydrate.

In the title compound, C(15)H(14)N(2)O(3)·H(2)O, the Schiff base mol-ecule is approximately planar, with a dihedral angle between the two aromatic rings of 10.2 (3)°. The mol-ecular structure is stabilized by O-H⋯N and N-H⋯O hydrogen bonds.