1-(2-Chloro­eth­yl)-1H-pyrazolo­[3,4-d]pyrimidin-4(5H)-one

In the title compound, C₇H₇ClN₄O, the pyrazolo­pyrimidine ring is essentially planar, the r.m.s. deviation of the fitted atoms being 0.0071 Å. The crystal structure features strong N—H...O hydrogen bonds and further consolidated by weak C—H...O, C—H...N and C—H...Cl inter­actions.

4-Imino-2,7-dimethyl-5,6,7,8-tetra­hydro-4H-1-benzothieno[2,3-d]pyrimidin-3-amine

In the title compound, C₁₂H₁₆N₄S, the fused benzothio­phene and the pyrimidine rings are coplanar [dihedral angle = 1.61 (6)°]. Three C atoms of the cyclohexene ring (at positions 3, 6 and 7) are disordered over two sites with an occupancy ratio of 0.702 (8):0.298 (8). The cyclo­hexene ring in both the major and minor components adopts a half-chair conformation. The crystal structure is stabilized by N—H...N and C—H...N inter­actions, resulting in the formation of inversion dimers with R₂²(10) and R₂²(12) graph-set motifs.

2-Amino-4-methyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile

In the title compound, C₁₀H₁₂N₂S, the thio­phene ring is essentially planar (r.m.s. deviation = 0.0290 Å). The two C atoms of the cyclo­hexene ring (at positions 6 and 7) are disordered over two sets of sites in a 0.810 (5):0.190 (5) ratio. The cyclo­hexene rings in both the major and minor occupancy conformers adopt a half-chair conformation. In the crystal, there are two types of N—H...N inter­action. One of these results in centrosymmetric head-to-head dimers corresponding to an R₂²(12) graph-set motif and the other forms a 20-membered macrocyclic ring involving six mol­ecules.