The asymmetric unit of the title compound, C(15)H(15)N(3)O(2)S, contains two independent mol-ecules corresponding to the R and S enanti-omers. The dihydro-pyrimidinone rings adopt a flattened boat conformation. One of the ethyl groups is disordered over two orientations with occupancy factors of 0.700 (7) and 0.300 (7). In the crystal structure, mol-ecules are linked by inter-molecular N-H⋯O hydrogen-bonding inter-actions into one-dimensional chains along the c-axis direction. The chains are further connected by N-H⋯S hydrogen bonds, forming a three-dimensional network.