In the title compound, C(22)H(21)NOS, the thio-pyran-one ring adopts a chair-like conformation with the substituent in the axial position. The relative configuration of the racemic compound is 3R,7S according to the numbering scheme used in this publication. In the crystal packing, centrosymmetric dimers are built up via N-H⋯O hydrogen bonds, with graph set R(2) (2)(8).