Crystal structure, Hirshfeld surface analysis and interaction energy, DFT and antibacterial activity studies of ethyl 2-[(2Z)-2-(2-chlorobenzylidene)-3-oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl]acetate

Abstract

The title compound, C19H16ClNO3S, consists of chlorophenyl methylidene and dihydrobenzothiazine units linked to an acetate moiety, where the thiazine ring adopts a screw-boat conformation. In the crystal, two sets of weak C—HPh...ODbt (Ph = phenyl and Dbt = dihydrobenzothiazine) hydrogen bonds form layers of molecules parallel to the bc plane. The layers stack along the a-axis direction with intercalation of the ester chains. The crystal studied was a two component twin with a refined BASF of 0.34961 (5). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H...H (37.5%), H...C/C...H (24.6%) and H...O/O...H (16.7%) interactions. Hydrogen-bonding and van der Waals interactions are the dominant interactions in the crystal packing. Computational chemistry indicates that in the crystal, C—HPh...ODbt hydrogen bond energies are 38.3 and 30.3 kJ mol−1. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 G(d,p) level are compared with the experimentally determined molecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap. Moreover, the antibacterial activity of the title compound has been evaluated against gram-positive and gram-negative bacteria.

Crystal structure, Hirshfeld surface and crystal void analysis, intermolecular interaction energies, DFT calculations and energy frameworks of 2H-benzo[b][1,4]thiazin-3(4H)-one 1,1-dioxide

“…Numerous heterocyclic compounds containing sulfur and nitrogen have been extensively studied because of their various biological applications (Gowda et al, 2011;Sebbar et al, 2020a;Fringuelli et al, 2005). In this respect, 1,4-benzothiazine derivatives possess various pharmacological properties and have therapeutic applications such as antifungal (Kamila et al, 2006), anti-inflammatory (Gowda et al, 2011, antagonistic (Corelli et al, 1997), anti-tumour (Abbas & Farghaly, 2010), antioxidant (Bakavoli et al, 2008), antipyretic (Warren & Knaus, 1987), antihypertensive (Fringuelli et al, 2005) or antibacterial effects (Sebbar et al, 2016(Sebbar et al, , 2020a.…”