7-Methyl-5,6,7,8-tetra-hydro-1-benzo-thieno[2,3-d]pyrimidin-4-amine.

In the title compound, C(11)H(13)N(3)S, two of the C atoms of the cyclo-hexene ring and the methyl group attached to it are disordered over two sets of sites in a 0.544 (2):0.456 (2) ratio. The benzothiene and pyrimidine rings are almost coplanar with an angular tilt of 2.371 (9)° between them. The thio-phene ring is essentially planar (r.m.s. deviation 0.05 Å), while the cyclo-hexene ring in both the major- and minor-occupancy conformers adopts a half-chair conformation. In the crystal structure, pairs of intermolecular N-H⋯N hydrogen bonds involving the amino groups result in centrosymmetric head-to-head dimers about inversion centres, corresponding to an R(2) (2)(8) graph-set motif. Further, N-H⋯N hydrogen bonding generates a two-dimensional hydrogen-bonded network perpendicular to the ac plane and running along the diagonal of the ac plane.

6-(4-Bromo-phen-yl)-2-(4-fluoro-benz-yl)imidazo[2,1-b][1,3,4]thia-diazole.

In the title compound, C(17)H(11)BrFN(3)S, the imidazothia-diazole and bromo-phenyl rings are individually almost planar, with maximum deviations of 0.0215 (4) and 0.0044 (4) Å, respectively, and are inclined at an angle of 27.34 (3)° with respect to each other. The dihedral angle between the mean planes of the fluoro-benzyl and imidazothia-diazole rings is 79.54 (3)°. The crystal structure is stabilized by inter-molecular C-H⋯N inter-actions resulting in chains of mol-ecules along the b axis.

3-{[6-(4-Chloro-phen-yl)imidazo[2,1-b][1,3,4]thia-diazol-2-yl]meth-yl}-1,2-benzoxazole.

In the title compound, C(18)H(11)ClN(4)OS, the benzisoxazole and imidazothia-diazole rings are inclined at an angle of 23.81 (7)° with respect to each other. The imidazothia-diazole and chloro-phenyl rings make a dihedral angle of 27.34 (3)°. In the crystal, inter-molecular C-H⋯N inter-actions generate a chain along the c axis and C-H⋯O inter-actions form centrosymmetric dimers resulting in an R(2) (2)(26) graph-set motif. Moreover, the C-H⋯N and S⋯N [3.206 (4) Å] inter-actions links the mol-ecules into R(7) ring motifs. The packing is further stabilized by π-π stacking inter-actions between the thia-diazole rings with a shortest centroid-centroid distance of 3.497 (3) Å. In addition, C-H⋯π inter-actions are observed in the crystal structure.

2-Amino-6-methyl-4,5,6,7-tetra-hydro-1-benzothio-phene-3-carbonitrile.

In the title compound, C(10)H(12)N(2)S, one of the C atoms of the cyclo-hexene ring (at position 6) and the methyl group attached to it are disordered over two sets of sites in a 0.650 (3):0.350 (3) ratio. The cyclo-hexene ring in both the major and minor occupancy conformers adopts a half-chair conformation. The thio-phene ring is essentially planar (r.m.s. deviation = 0.05 Å). In the crystal, N-H⋯N hydrogen bonds involving the amino groups result in inversion dimers with R(2) (2)(12) graph-set motif. Further N-H⋯N hydrogen bonds involving the amino and carbonitrile groups generate zigzag chains along the a axis.

2-Amino-7-oxo-4,5,6,7-tetra-hydro-1-benzothio-phene-3-carbonitrile.

In the title compound, C(9)H(8)N(2)OS, the benzothio-phene ring is substituted with amino, oxo and carbonitrile groups. The thio-phene ring is essentially planar (r.m.s. deviation = 0.0003 Å), while the cyclo-hexene ring is in a half-chair conformation. In the crystal, N-H⋯O hydrogen bonds generate chains of mol-ecules in a zigzag pattern along the b axis. Pairs of N-H⋯N hydrogen bonds form centrosymmetric head-to-head dimers about inversion centres, corresponding to an R(2) (2)(12) graph-set motif. In addition, rather weak N-H⋯S inter-actions are also present in the structure and the supra-molecular assembly is further consolidated by π-π stacking inter-actions between the benzothio-phene rings, disposed at a distance of 3.742 (3) Å.

3-{[5-(4-Bromo-phen-yl)imidazo[2,1-b][1,3,4]thia-diazol-2-yl]meth-yl}-1,2-benzoxazole.

In the title compound, C(18)H(11)BrN(4)OS, the imidazothia-diazole and benzisoxazole rings are individually planar with maximum deviations of 0.025 (3) 0.015 (4) Å, respectively, and are inclined at an angle of 23.51 (7)° with respect to each other. The planes of the imidazothia-diazole and bromo-phenyl rings are inclined at an angle of 27.34 (3)°. In the crystal, inter-molecular C-H⋯N inter-actions result in chains of mol-ecules along the b and c axes. Moreover, C-H⋯O inter-actions result in centrosymmetric head-to-head dimers with R(2) (2)(24) graph-set motifs. The mol-ecular packing is further stabilized by π-π stacking inter-actions between the imidazole rings with a shortest centroid-centroid distance of 3.492 (3) Å. In addition, C-H⋯π inter-actions are observed in the crystal structure.