2-[2-(4-Nitro-phenyl)hy-dra-zin-yl-idene]malononitrile.

The title compound, C(10)H(8)N(8), is close to planar (r.m.s. deviation from the mean plane = 0.118 Å). In the crystal, inversion dimers linked by pairs of N-H⋯N hydrogen bonds generate R(2) (2)(12) loops.

Methyl 4-(3-chloro-prop-oxy)-3-methoxy-benzoate.

In the title compound, C(12)H(15)ClO(4), the molecules are linked by C-H⋯O interactions.

4-[4-(4-Nitro-phenyl-diazen-yl)phen-yl]hexa-nenitrile.

In the mol-ecule of the title compound, C(18)H(18)N(4)O(2), the aromatic rings are oriented at a dihedral angle of 3.72 (3)°. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers. There are also C-H⋯π inter-actions.

Methyl 4-but-oxy-3-methoxy-benzoate.

The title compound, C(13)H(18)O(4), is an inter-mediate product in the synthesis of quinazoline derivatives. Crystal structure analysis shows that the benzene-butoxy C(ar)-O-C-C torsion angle is 175.3 (2)° and that the benzene-methoxycarbonyl C(ar)-C-O-C torsion angle is 175.2 (2)°. Torsion angles close to 180° indicate that the molecule is almost planar.

Bis{6-[4-(2-ethyoxyphenyl-diazen-yl)phen-oxy]hexa-nol} monohydrate.

The asymmetric unit of the title compound, 2C(20)H(26)N(2)O(3)·H(2)O, contains two independent mol-ecules and one water mol-ecule. The azo bonds adopt trans conformations and the dihedral angles between the aromatic rings in the two organic mol-ecules are 4.5 (2) and 1.5 (2)°. In the crystal structure, O-H⋯O and C-H⋯O hydrogen bonds help to establish the packing.

Methyl 5-meth-oxy-2-nitro-4-[3-(piperidin-1-yl)prop-oxy]benzoate.

In the mol-ecule of the title compound, C(17)H(24)N(2)O(6), the dihedral angle between the four coplanar atoms of the piperidine ring and the benzene ring is 39.2 (1)°.

2-{3,4-Dibut-oxy-5-[5-(3-methyl-phen-yl)-1,3,4-oxadiazol-2-yl]thio-phen-2-yl}-5-(3-methyl-phen-yl)-1,3,4-oxadiazole.

In the title compound, C(30)H(32)N(4)O(4)S, the dihedral angles between the central thio-phene ring and the pendant oxadiazole rings are 10.1 (2) and 6.8 (3)°. The dihedral angles between each oxadiazole ring and its adjacent benzene ring are 6.8 (2) and 5.3 (3)°.

Methyl 4-(3-chloro-prop-oxy)-5-meth-oxy-2-nitro-benzoate.

The asymmetric unit of the title compound, C(12)H(14)ClNO(6), contains two crystallographically independent mol-ecules, in which the benzene rings are oriented at a dihedral angle of 9.12 (3)°. In the crystal structure, weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional network.

N-(4-Isopropoxyphen-yl)acetamide.

In the mol-ecule of the title compound, C(11)H(15)NO(2), the planar acetamide unit [maximum deviation of 0.0014 (6) Å] is oriented at a dihedral angle of 19.68 (4)° with respect to the aromatic ring. An intra-molecular C-H⋯O inter-action results in the formation of a six-membered ring. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains along the a axis.

Methyl 2-amino-4-(3-chloro-prop-oxy)-5-methoxy-benzoate.

The asymmetric unit of the title compound, C(12)H(16)ClNO(4), contains two crystallographically independent mol-ecules. The benzene rings of the two independent mol-ecules are oriented at a dihedral angle of 88.50 (3)°. Intra-molecular N-H⋯O hydrogen bonds involving the methoxybenzoate carbonyl group in each molecule result in the formation of two planar, six-membered rings, oriented at dihedral angles of 1.39 (3) and 0.68 (3)° with respect to the adjacent benzene rings. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains along the a axis.

5-Chloro-pyrimidin-2-amine.

The complete mol-ecule of the title compound, C(4)H(3)ClN(3), is generated by crystallographic mirror symmetry, with the Cl atom, one N atom and two C atoms lying on the reflecting plane. In the crystal structure, inter-molecular N-H⋯N hydrogen bonds link the mol-ecules into chains propagating in [100].

2-(4-Chloro-phen-yl)-5-{3,4-dibut-oxy-5-[5-(4-chloro-phen-yl)-1,3,4-oxadiazol-2-yl]thio-phen-2-yl}-1,3,4-oxadiazole.

In the title compound, C(28)H(26)Cl(2)N(4)O(4)S, the dihedral angles between the two chloro-phenyl rings and the two oxadiazol rings are 10.51 (4)° and 13.55 (3)°, respectively. The thio-phene ring is oriented at dihedral angles of 5.59 (4)°, 8.33 (4)° and 4.41 (4)°, 11.05 (3)°, respectively, with respect to the two oxadiazol and the two chloro-phenyl rings. The intra-molecular C-H⋯O hydrogen bond results in the formation of a five-membered ring. In the crystal structure, π-π contacts between the oxadiazol rings, the chloro-phenyl rings and the chloro-phenyl and oxadiazol rings [centroid-centroid distances = 3.428 (3) Å, 3.750 (3) Šand 3.768 (3) Å, respectively] are present.

1-Methyl-1H-indazole-3-carboxylic acid.

The asymmetric unit of the title compound, C(9)H(8)N(2)O(2), contains two mol-ecules. In the crystal structure, both mol-ecules form inversion dimers via pairs of O-H⋯O hydrogen bonds, and a C-H⋯O inter-ation is also seen.

2-Methyl-3-nitro-benzonitrile.

The asymmetric unit of the title compound, C(8)H(6)N(2)O(2), contains two independent mol-ecules, the aromatic rings of which are oriented at a dihedral angle of 1.68 (3)°. Intra-molecular C-H⋯O hydrogen bonds result in the formation of two non-planar six-membered rings, which adopt envelope and twisted conformations. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules. There are π-π contacts between the benzene rings [centroid-centroid distances = 3.752 (3) and 3.874 (3) Å].