3-Butyl-2-propyl-amino-1-benzo-thieno[3,2-d]pyrimidin-4(3H)-one.

In the title compound, C(17)H(21)N(3)OS, the propyl and butyl groups are disordered over two positions; site occupation factors are 0.304 (10) and 0.696 (10). The three fused rings are coplanar. In the crystal structure, inter-molecular N-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules. Further stability is provided by offset π-π stacking inter-actions. Adjacent thienophene-pyrimidine and pyrimidine-benzene rings have centroid-centroid distances of 3.96 (1) and 3.55 (2) Å, respectively.