(E)-4-[(3,5-Dimethyl-phen-yl)imino-meth-yl]-2-meth-oxy-3-nitro-phenol.

The mol-ecule of the title compound, C(16)H(16)N(2)O(4), exists in the E configuration with respect to the central C=N double bond. The dihedral angle between the two benzene rings is 2.17 (9) Å. In the crystal, mol-ecules are linked via O-H⋯N hydrogen bonds into chains that propagate along the b-axis direction. There is also π-π stacking of inversion-related mol-ecules, with inter-planar spacings of 3.479 (5) Šand ring centroid-centroid distances of 3.876 (4) Å.

5-Bromo-2-meth-oxy-4-{[(4-meth-oxy-phen-yl)imino]-meth-yl}phenol monohydrate.

The crystal structure of the title compound, C(15)H(14)BrNO(3)·H(2)O, has a trans configuration about the central C=N double bond. An intra-molecular O-H⋯O hydrogen bond occurs in the main mol-ecule. The crystal packing is stabilized by strong O-H⋯O and O-H⋯N hydrogen bonds.

4-[(E)-(3-Chloro-4-methyl-phen-yl)imino-meth-yl]-2-methoxy-3-nitro-phenyl acetate.

The title compound, C(17)H(15)ClN(2)O(5), displays a trans-configuration with respect to the C=N double bond. The mol-ecule is twisted, the dihedral angle between the mean planes of the two benzene rings being 18.70 (12)°. The nitro, meth-oxy and acetyl groups are oriented at 80.70 (11), 35.2 (2) and 72.35 (10)°, respectively, to the benzene ring to which they are bonded. The crystal structure is stabilized by weak C-H⋯O hydrogen-bonding contacts.