Syntheses and structures of spontaneously resolved (2S)-2-phenyl-3-(thiazol-2-yl)-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one and racemic 2-(furan-2-yl)-3-phenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one

The title compounds, one a thiazole derivative: (2S)-2-phenyl-3-(thiazol-2-yl)-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one, C13H12N2OS2, and the second a furan derivative: (rac)-2-(furan-2-yl)-3-phenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one, C14H13NO2S, crystallize in space-groups P212121 and P21/c, respectively, with a single molecule in their asymmetric units. The crystal of the thiazole derivative chosen for data collection was found to consist of the S enantiomer [Flack parameter 0.013(9)]. The crystal of the furan derivative in the centrosymmetric space group is a racemic mixture. The puckering of the thiazine ring in both the structures is a half-chair. The extended structure of the thiazole derivative shows two weak C - H⋯O type interactions, but no aromatic ring interactions. In the structure of the furan derivative, an extensive and continuous network of C - H⋯O hydrogen bonds between the furan and the substituted thiazine ring, and also between symmetry-related furan rings, results in a continuous amphiphilic layer lying parallel to the (100) plane. Adjacent to this plane is the layer of hydrophobic phenyl rings. Thus, the extended structure comprises alternating layers of amphiphilic and hydrophobic regions, stacked in the a-axis direction. A C - H⋯O interaction between the phenyl ring and the thiazin-4-one moiety and the π-π stacking of the phenyl rings between pairs of symmetry-related molecules further consolidates the extended structure.