4-[(1-Benzyl-1,2,3-triazol-5-yl)methyl]-2H-1,4-benzothiazin-3(4H)-one

The asymmetric unit of the title compound, C18H16N4OS, contains two independent molecules of similar conformation, the most relevant difference being the dihedral angle formed by the benzene rings [57.8 (2) and 52.7 (2)°]. The six-membered heterocycle of the benzothiazine fragment exhibits a screw-boat conformation in both molecules. The plane through the triazole ring is nearly perpendicular to those through the fused and terminal benzene rings [dihedral angles of 74.2 (2) and 83.2 (2)° in one molecule, and 77.8 (2) and 82.9 (2)° in the other]. In the crystal, molecules are linked by C—H⋯N and C—H⋯O hydrogen bonds into chains parallel to the a-axis direction. The crystal used was a non-merohedral twin, the refined ratio of twin components being 0.85 (10):15 (10).

The asymmetric unit of the title compound, C 18 H 16 N 4 OS, contains two independent molecules of similar conformation, the most relevant difference being the dihedral angle formed by the benzene rings [57.8 (2) and 52.7 (2) ]. The sixmembered heterocycle of the benzothiazine fragment exhibits a screw-boat conformation in both molecules. The plane through the triazole ring is nearly perpendicular to those through the fused and terminal benzene rings [dihedral angles of 74.2 (2) and 83.2 (2) in one molecule, and 77.8 (2) and 82.9 (2) in the other]. In the crystal, molecules are linked by C-HÁ Á ÁN and C-HÁ Á ÁO hydrogen bonds into chains parallel to the a-axis direction. The crystal used was a non-merohedral twin, the refined ratio of twin components being 0.85 (10):15 (10).   Table 1 Hydrogen-bond geometry (Å , ). Symmetry codes: (i) x; y þ 1; z; (ii) x À 1 2 ; Ày þ 1 2 ; z; (iii) x; y À 1; z.

Comment
Benzothiazine derivatives have extensively been studied in different areas of chemistry including the pharmaceutical and other chemical industries. With respect to biological applications, these derivatives have been found to be potent antiinflammatories (Chia et al., 2008), anti-microbials (Barazarte et al., 2008), herbicidals (Takemoto et al., 1994 and fungicidals (Yaltirik et al., 2001). The present work is a continuation of the investigation of the benzothiazine derivatives published recently by our team, including the isomer of the present compound (Sebbar et al., 2014).
Moreover, the dihedral angle between the two benzene rings is of 57.8 (2)°. Nearly the same values are observed in the second molecule (S2/O2/N5-N8/C19-C36; 77.8 (2)°; 82.9 (2)° and 52.7 (2)°). The most important differences between the conformations of the present molecule and its isomer, recently published, are the values of the dihedral angles between the benzene rings. In the crystal, the molecules are linked by intermolecular C-H···N and C-H···O hydrogen interactions (Table 1) to form wavy chains parallel to the a axis.

Refinement
All H atoms were located in a difference Fourier map and treated as riding, with C-H = 0.93-0.97 Å and with U iso (H) = 1.2 U eq (C). The crystal used for the diffraction study was a non-merohedral twin (twin law 1 0 0, 0 -1 0, 0 0 -1) with a

Figure 1
The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are represented as small circles.

4-[(1-Benzyl-1,2,3-triazol-5-yl)methyl]-2H-1,4-benzothiazin-3(4H)-one
where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.61 e Å −3 Δρ min = −0.23 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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 R-factors(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.