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

The title compounds, one a thia-zole derivative: (2<i>S</i>)-2-phenyl-3-(thia-zol-2-yl)-2,3,5,6-tetra-hydro-4<i>H</i>-1,3-thia-zin-4-one, C₁₃H₁₂N₂OS₂, and the second a furan derivative: (<i>rac</i>)-2-(furan-2-yl)-3-phenyl-2,3,5,6-tetra-hydro-4<i>H</i>-1,3-thia-zin-4-one, C₁₄H₁₃NO₂S, crystallize in space-groups <i>P</i>2₁2₁2₁ and <i>P</i>2₁/<i>c</i>, respectively, with a single mol-ecule in their asymmetric units. The crystal of the thia-zole derivative chosen for data collection was found to consist of the <i>S</i> enanti-omer [Flack parameter 0.013 (9)]. The crystal of the furan derivative in the centrosymmetric space group is a racemic mixture. The puckering of the thia-zine ring in both the structures is a half-chair. The extended structure of the thia-zole derivative shows two weak C-H⋯O type inter-actions, but no aromatic ring inter-actions. In the structure of the furan derivative, an extensive and continuous network of C-H⋯O hydrogen bonds between the furan and the substituted thia-zine 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 hydro-phobic phenyl rings. Thus, the extended structure comprises alternating layers of amphiphilic and hydro-phobic regions, stacked in the <i>a</i>-axis direction. A C-H⋯O inter-action between the phenyl ring and the thia-zin-4-one moiety and the π-π stacking of the phenyl rings between pairs of symmetry-related mol-ecules further consolidates the extended structure.