(2E)-2-(4-Hy­droxy-3-meth­oxy­benzyl­idene)hydrazinecarboxamide

In the title compound, C₉H₁₁N₃O₃, two mol­ecules are present in the asymmetric unit in which the 4-hy­droxy-3-meth­oxy­benzaldehyde and hydrazinecarboxamide units are almost planar [with r.m.s. deviations 0.0212 and 0.0066 Å, respectively, in one mol­ecule and 0.0346 and 0.0095 Å, respectively, in the other] and are oriented at dihedral angles of 9.7 (3) and 16.6 (3)°. In both mol­ecules, two S(5) ring motifs are present due to N—H...N and O—H...O hydrogen bonds. In the crystal, the mol­ecules are dimerized with each other due to pairs of N—H...O hydrogen bonds, forming an R₂²(8) ring motif. O—H...O hydrogen bonds lead to the formation of a three-dimensional network.

3-[(E)-(Pyridin-3-yl­imino)­meth­yl]phenol

Two independent mol­ecules are present in the asymmetric unit of the title compound, C₁₂H₁₀N₂O, in which the 3-hy­droxy­benzaldehyde and the pyridin-3-amine units are almost planar [r.m.s. deviations of 0.0236 and 0.0116Å, respectively, in one mol­ecule and 0.0245 and 0.0162Å, respectively, in the other] and are oriented at dihedral angles of 7.21 (7) and 14.77 (7)°. In the crystal, mol­ecules of the same type form inversion dimers via pairs of O—H...N hydrogen bonds, forming R₂²(20) ring motifs. There exist π–π inter­actions between the benzene and pyridine rings of molecules of the same type with centroid–centroid distances of 3.7127 (10) and 3.8439 (10) Å.

4-Bromo-2-{(E)-[(3,4-dimethyl­phen­yl)imino]­meth­yl}phenol

In the title compound, C₁₅H₁₄BrNO, the dihedral angle between the aromatic rings is 4.10 (11)° and the mol­ecule is close to planar (r.m.s. deviation for the non-H atoms = 0.053 Å). An intra­molecular O—H...N hydrogen bond closes an S(6) ring. In the crystal, very weak C—H...π inter­actions are observed.