Crystal structure of 3-benzylsulfanyl-6-(5-methyl-1,2-oxazol-3-yl)-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole

In the title compound, C14H11N5OS2, the triazolo–thiadiazole system is essentially planar (r.m.s. deviation = 0.002 Å) and makes dihedral angles of 6.33 (12) and 42.95 (14)° with the planes of the oxazole and phenyl rings, respectively. In the crystal, face-to-face π–π interactions are observed between the thiadiazole and oxazole rings [centroid–centroid distance = 3.4707 (18) Å], leading to columns along [010].

All the bond lengths and bond angles in the compound are within normal ranges and comparable with those reported in a similar compound (Dinçer et al., 2005).

S2. Experimental
The title compound was synthesized according to the published procedure (Vaarla & Rao, 2014). The compound was synthesized in two steps. In step one, a mixture containing equivalent amounts of 5-methylisoxazole-3-carboxylic acid and 4-amino-4H-[1,2,4]triazole-3,5-dithiol was refluxed in the presence of phosphorus oxychloride for about 5 h. After monitoring by TLC, the reaction mixture was cooled to room temperature and poured into crushed ice. The separated solid was filtered, dried and recrystallized from methanol.

S3. Refinement
All H atoms were placed in calculated positions with C-H = 0.93 to 0.97 Å, refined in the riding model with U iso (H) parameters set to 1.2U eq (C) or 1.5U eq (CH 3 only). The (0 0 -2), (2 0 1) and (2 0 0) reflections, whose intensities were supporting information affected by the beamstop, were removed from the final refinement.

Figure 1
The title molecule with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level.

Figure 2
View of the molecular packing of the title compound down the b axis. All H atoms have been omitted for clarity.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.