2-(6-Phenyl-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazin-3-yl)-1,3-benzothiazole

In the title compound, C17H11N5S2, the dihedral angles formed between the triazole ring and the benzene ring and the 1,3-benzothiazole ring system are 8.67 (8) and 13.90 (9)°, respectively. The conformation of the triazolo-thiadiazin-3-yl fused ring system is a twisted half-chair. Overall, the molecule adopts a flattened shape. Supramolecular helical chains along the a axis sustained by C—H⋯N interactions are found in the crystal structure. These are linked via C—H⋯π contacts as well as π–π [centroid–centroid distance = 3.5911 (12) Å] interactions between the triazole and thiazole rings.

In the title compound, C 17 H 11 N 5 S 2 , the dihedral angles formed between the triazole ring and the benzene ring and the 1,3benzothiazole ring system are 8.67 (8) and 13.90 (9) , respectively. The conformation of the triazolo-thiadiazin-3-yl fused ring system is a twisted half-chair. Overall, the molecule adopts a flattened shape. Supramolecular helical chains along the a axis sustained by C-HÁ Á ÁN interactions are found in the crystal structure. These are linked via C-HÁ Á Á contacts as well as -[centroid-centroid distance = 3.5911 (12) Å ] interactions between the triazole and thiazole rings.

Experimental
Cg1 is the centroid of the C12-C17 ring.
In the crystal packing, C-H···N interactions, Table 1, lead to the formation of supramolecular chains along the a axis with an helical topology, Fig. 2. These assemble into zigzag layers in the ac plane with connections between them of the type C-H···π involving a methylene-H and the benzene ring, and π···π. The shortest interaction of the latter type of 3.5911 (12) Å occurs between the S1,N1,C1,C6,C7 and N2-N4,C8,C9 five-membered rings, Fig. 3.

Experimental
The title compound was prepared according to the reported method (Abdel-Aziz et al., 2007). Colourless crystals were obtained from an EtOH/DMF (v/v = 2/1) solution by slow evaporation at room temperature.

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H 0.95 to 0.99 Å, U iso (H) 1.2U eq (C)] and were included in the refinement in the riding model approximation. Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.

Figures
supplementary materials sup-2   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.