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.