Abstract
The title compound, C18H12Cl2N2OS, consists of a di-hydro-benzo-thia-zine unit linked by a -CH group to a 2,4-di-chloro-phenyl substituent, and to a propane-nitrile unit is folded along the S⋯N axis and adopts a flattened-boat conformation. The propane-nitrile moiety is nearly perpendicular to the mean plane of the di-hydro-benzo-thia-zine unit. In the crystal, C-HBnz⋯NPrpnit and C-HPrpnit⋯OThz (Bnz = benzene, Prpnit = propane-nitrile and Thz = thia-zine) hydrogen bonds link the mol-ecules into inversion dimers, enclosing R 2 2(16) and R 2 2(12) ring motifs, which are linked into stepped ribbons extending along [110]. The ribbons are linked in pairs by complementary C=O⋯Cl inter-actions. π-π contacts between the benzene and phenyl rings, [centroid-centroid distance = 3.974 (1) Å] may further stabilize the structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (23.4%), H⋯Cl/Cl⋯H (19.5%), H⋯C/C⋯H (13.5%), H⋯N/N⋯H (13.3%), C⋯C (10.4%) and H⋯O/O⋯H (5.1%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. Computational chemistry calculations indicate that the two independent C-HBnz⋯NPrpnit and C-HPrpnit⋯OThz hydrogen bonds in the crystal impart about the same energy (ca 43 kJ mol-1). Density functional theory (DFT) optimized structures at the B3LYP/6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.
Highlights
Nada Kheira Sebbar,a,b* Brahim Hni,b Tuncer Hokelek,c Abdelhakim Jaouhar,a Mohamed Labd Taha,a Joel T
The title compound, C18H12Cl2N2OS, consists of a dihydrobenzothiazine unit linked by a –CH group to a 2,4-dichlorophenyl substituent, and to a propanenitrile unit is folded along the SÁ Á ÁN axis and adopts a flattened-boat conformation
C—HBnzÁ Á ÁNPrpnit and C—HPrpnitÁ Á ÁOThz (Bnz = benzene, Prpnit = propanenitrile and Thz = thiazine) hydrogen bonds link the molecules into inversion dimers, enclosing R22(16) and R22(12) ring motifs, which are linked into stepped ribbons extending along [110]
Summary
1,4-Benzothiazine derivatives constitute an important class of heterocyclic systems. These molecules exhibit a wide range of biological applications indicating that the 1,4-benzothiazine moiety is a potentially useful template in medicinal chemistry research and has therapeutic applications as anti-inflammatory (Trapani et al, 1985; Gowda et al, 2011), antipyretic (Warren & Knaus, 1987), anti-microbial (Armenise et al, 2012; Rathore & Kumar, 2006; Sabatini et al, 2008), anti-viral (Malagu et al, 1998), anti-cancer (Gupta et al, 1985; Gupta & Gupta, 1991) and anti-oxidant (Zia-ur-Rehman et al, 2009) agents. 1,4-Benzothiazine derivatives have been reported as precursors for the syntheses of new compounds (Sebbar et al, 2015a; Vidal et al, 2006) possessing anti-diabetic (Tawada et al, 1990) and anti-corrosion activities In heterocyclic ring B, the C1—S1—C8 [103.69 (9)], S1—C8— C7 [121.12 (14)], C8—C7—N1 [120.59 (17)], C7—N1—C6 [126.27 (16)], C6—C1—S1 [123.84 (15)] and N1—C6—C1 [121.46 (17)] bond angles are enlarged when compared with the corresponding values in the closely related compounds, (2Z)-2-(4-chlorobenzylidene)-4-[2-(2-oxooxazoliden-3-yl) ethyl]-3,4-dihydro-2H-1,4-benzothiazin-3-one, (II), (Ellouz et al, 2017a) and (2Z)-2-[(4-fluorobenzylidene]-4-(prop-2-yn-1yl)-3,4 -dihydro-2H-1,4-benzothiazin-3-one, (III), (Hni et al, 2019a), and are nearly the same as the corresponding values in (2Z)-4-[2-(2-oxo-1,3-oxazolidin-3-yl)ethyl]-2(phenylmethylidene)-3,4-dihydro-2H-1,4-benzothiazin-3-one, (IV), (Sebbar et al, 2016b) and (2Z)-2-[(2,4-dichlorophenyl)methylidene]-4-[2-(2-oxo-1,3-oxazolidin-3-yl)ethyl]3,4-dihydro-2H-1,4-benzothiazin-3-one, (V), (Hni et al, 2019b), where the heterocyclic portions of the dihydrobenzothiazine units are planar in (IV) and non-planar in (II), (III) and (V)
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