In the title Schiff base, C(18)H(22)N(4)O, the hexa-hydro-pyrimidinyl ring adopts a chair conformation. The dihedral angle between the aromatic rings of the 4-(2-phenyl-diazen-yl)phenol unit is 15.7 (1)°. There is an intra-molecular O-H⋯N hydrogen bond between the hydroxyl group and an N atom of the hexa-hydro-pyimidinyl unit. Inter-molecular N-H⋯O and N-H⋯N hydrogen bonds give rise to a layer ...

In the structure of title compound, C(22)H(20)O(2)N(2), the 11-membered benzodiazepine ring system adopts a distorted boat conformation. The benzene ring of this system forms dihedral angles of 89.69 (12) and 48.82 (12)° with those of the phenol and methoxy-phenyl substituents, respectively. The dihedral angle between the benzene rings is 49.61 (11)°. An intra-molecular O-H⋯N hydrogen bond gene...

In the title compound, C(24)H(28)N(2)O(4)S, the dihedral angle between the phenol ring and the thia-zole ring system is 10.6 (1)°, and the trimethoxy-phenyl group is approximately perpendicular to the thia-zole ring, the dihedral angle being 84.7 (2)°. There is a strong intra-molecular hydrogen-bonding inter-action between the Schiff base and the hydr-oxy group.

In the title compound, C(15)H(15)NO(2), the phenol group make dihedral angles of 2.4 (2) and 24.1 (9)° with the imine linkage (-C=N-) and the phenyl group, respectively, and the mol-ecule adopts the enol-imine tautomeric form, so the mol-ecular structure is stabilized by a strong intra-molecular O-H⋯N hydrogen bond. The crystal structure features a weak C-H⋯π inter-action.

The title compound, C(20)H(12)N(2)S(2), was prepared by the reaction of o-phthalic acid and 2-amino-thio-phenol under microwave irradation. The phenyl ring, A, and the benzothia-zolyl rings, B and C, are planar; the dihedral angles are A/B = 19.9 (11), A/C = 87.8 (3) and B/C = 84.4 (4)°. Weak inter-molecular C-H⋯N hydrogen bonds link the mol-ecule, forming zigzag chains parallel to the c axis.

In the title compound, C(27)H(19)N(3)O(4), the phenol and pyrazole rings are almost coplanar [dihedral angle = 0.95 (12)°] due to an intra-molecular O-H⋯N hydrogen bond, whereas the phenyl ring is tilted by 40.81 (7)° with respect to the plane of the pyrazole ring. The aromatic ring with a nitro-phen-oxy substituent makes a dihedral angle of 54.10 (7)° with the pyrazole ring.

The title chiral photochromic Schiff base compound, C(21)H(19)N(3)O, was synthesized from (R)-1-phenyl-ethyl-amine and the salicylaldehyde of an azobenzene derivative. The mol-ecule corresponds to the phenol-imine tautomer, the C=N and N-C bond distances being 1.279 (3) and 1.477 (3) Å, respectively. An intra-molecular O-H⋯N hydrogen bond occurs. The diazenyl group adopts a trans form with an N...

In the mol-ecular structure of the title Schiff base, C14H10Br2ClNO, the chloro-phenyl ring and di-bromo-phenol ring are almost coplanar; the dihedral angle between the planes of the two rings is 10.50 (18)°. There is an intra-molecular O-H⋯N hydrogen bond, with an O⋯N distance of 2.576 (4)Å. The crystal structure is stabilized by π-π stacking of neighbouring aromatic rings along the b-axis dir...