Abdul Qayyum Ather

3-(Piperidin-1-yl)-6-(1H-pyrazol-1-yl)pyridazine

In the title compound, C12H15N5, the piperidine ring adopts a chair conformation with the substituent C atom in an equatorial site and the dihedral angle between the pyridazine and pyrazole ring planes is 10.36 (2)°.

N-(2-Methyl­phen­yl)-6-(1H-pyrazol-1-yl)pyridazin-3-amine

The title compound, C14H13N5, crystallizes with two crystallographically independent molecules in the unit cell. The two molecules form dimers through intermolecular N—H⋯N and C—H⋯N hydrogen bonds. The hydrogen-bonding motifs are R 2 2(8) for both the N—H⋯N and C—H⋯N interactions. The pyrazole and pyrimidine rings form dihedral angles of 6.2 (3) and 8.3 (3)° with each other and the dihedral angles between the pyrazole and benzene rings are 54.9 (2) and 58.6 (2)°. The benzene rings of neighbouring dimers also exhibit C—H⋯π interactions.

(4Z)-4-[(2E)-1-Hy-droxy-3-(3-nitro-phen-yl)prop-2-en-1-yl-idene]-3-methyl-1-(4-methyl-phen-yl)-1H-pyrazol-5(4H)-one.

In the title compound, C20H17N3O4, the dihedral angles between the heterocyclic ring and the toluene and nitrobenzene rings are 4.21 (15) and 11.43 (14)°, respectively. The whole molecule is close to planar (r.m.s. deviation for the 27 non-H atoms = 0.171 Å). Two S(6) rings are formed due to intramolecular C—H⋯O and O—H⋯O hydrogen bonds. In the crystal, inversion dimers linked by pairs of C—H⋯O bonds generate R 2 2(10) loops and further C—H⋯O bonds link the dimers along the b-axis direction. There exist π–π interactions between the heterocyclic rings at a centroid–centroid distance of 3.7126 (10) Å and between the centroids of the benzene rings at a distance of 3.8710 (16) Å.

N-Phenyl-6-(1H-pyrazol-1-yl)pyridazin-3-amine

The molecule of title compound, C13H11N5, is essentially planar (r.m.s. deviation = 0.0440 Å) and an intramolecular C—H⋯N hydrogen bond generates an S(6) motif. In the crystal, molecules are connected into chains by intermolecular N—H⋯N and C—H⋯N hydrogen bonds. In addition, π–π stacking interactions are observed between the pyrazole and pyridazine rings [interplanar distance = 3.6859 (10) Å].

3,4-Dimethyl-1-phenyl­pyrano[2,3-c]pyrazol-6(1H)-one

In the title compound, C14H12N2O2, the dihedral angle between the phenyl ring and the 3,4-dimethylpyrano[2,3-c]pyrazol-6(1H)-one system is 7.28 (6)°. An intramolecular C—H⋯O interaction generates an S(6) ring. In the crystal, the molecules are linked by C—H⋯O hydrogen bonds, forming C(8) chains. C–H⋯π and π–π interactions [centroid–centroid separation = 3.6374 (12) Å] further consolidate the packing.

3-Chloro-6-[(E)-2-(1-phenyl­ethyl­idene)hydrazin­yl]pyridazine

Two independent molecules are present in the asymmetric unit of the title compound, C12H11ClN4, (Z′ = 2): the dihedral angles between the phenyl and pyridizine rings are 8.35 (10) and 37.64 (6)°. In the crystal, the two molecules form inversion dimers with R 2 2(8) ring motifs through intermolecular N—H⋯N hydrogen bonds. The crystal structure is stabilized by π–π interactions between the pyridazine rings of symmetry-related molecules. In one of the independent molecules, the centroid–centroid separations are 3.6927 (13) and 3.7961 (13) Å, whereas in the other, the separations are 3.6909 (13) and 3.9059 (13) Å.

3-[(2E)-2-(Butan-2-yl-idene)hydrazin-yl]-6-chloro-pyridazine.

The asymmetric unit of the title compound, C8H11ClN4, contains two independent molecules (A and B) with slightly different conformations: the dihedral angles between the 3-chloro-6-hydrazinylpyridazine units and butyl side chains are 4.5 (2) and 11.98 (16)°. In the crystal, the A and B molecules are linked by a pair of N—H⋯N hydogen bonds, generating an R 2 2(8) loop.

3-Chloro-6-[2-(cyclo­pentyl­idene)hydrazin-1-yl]pyridazine

The asymmetric unit of the title compound, C9H11ClN4, contains two virtually planar molecules that differ in conformation about the bond connecting the hydrazine and pyridazine units. The 3-chloro-6-hydrazinylpyridazine and cyclopentane groups are oriented at dihedral angles of 4.5 (3) and 8.8 (4)° in the two molecules. In the crystal, the molecules form a one dimensional polymeric structure extending along the a axis via N—H⋯N hydrogen bonds. The crystal stucired was an inversion twin [ratio of the twin domains = 0.73 (9):0.27 (9)].

3-Chloro-6-(1H-pyrazol-1-yl)pyridazine.

The title compound, C(7)H(5)ClN(4), is almost planar (r.m.s. deviation = 0.022 Å). The dihedral angle between the aromatic rings is 2.82 (5)°. The packing results in polymeric chains extending along the a axis. In the crystal, mol-ecules are connected to each other through inter-molecular C-H⋯N hydrogen bonds, resulting in R(2) (2)(10) ring motifs.

3-Chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridazine.

In the title compound, C9H9ClN4, the dihedral angle between the aromatic rings is 6.25 (9)°. The whole molecule is approximately planar (r.m.s. deviation = 0.070 Å). In the crystal, π–π interactions between the centroids of the pyridazine rings [separation = 3.5904 (10) Å] occur.