Crystal structure of 5-(adamantan-1-yl)-3-[(2-trifluoromethylanilino)methyl]-2,3-dihydro-1,3,4-oxadiazole-2-thione, C20H22F3N3OS

A combined crystallographic and theoretical investigation of noncovalent interactions in 1,3,4-oxadiazole-2-thione-N-Mannich derivatives: in vitro bioactivity and molecular docking

Two 1,3,4-oxadiazole-2-thione-N-Mannich derivatives, specifically 5-(4-chlorophenyl)-3-[(2-trifluoromethylphenylamino)methyl]-1,3,4-oxadiazole-2(3H)-thione (1) and 5-(4-chlorophenyl)-3-[(2,5-difluorophenylamino)methyl]-1,3,4-oxadiazole-2(3H)-thione (2), were synthesized and then characterized by elemental analysis and NMR (1H and 13C) spectroscopy and the single crystal X-ray diffraction method. The formed weak intermolecular interactions in the solid-state structures of these derivatives were thoroughly investigated utilizing a variety of theoretical tools such as Hirshfeld surface analysis and quantum theory of atoms in molecules (QTAIM). Furthermore, the CLP-PIXEL and density functional theory calculations were used to study the energetics of molecular dimers. Numerous weak intermolecular interactions such as C-H⋯S/Cl/F/π interactions, a directional C-Cl⋯Cl halogen bond, π-stacking, type C-F⋯F-C contact and a short F⋯O interaction, help to stabilize the crystal structure of 1. Crystal structure 2 also stabilizes with several weak intermolecular contacts, including N-H⋯S, C-H⋯N//Cl/F interactions, a highly directional C1-Cl1⋯C(π) halogen bond and C(π)⋯C(π) interaction. In vitro antimicrobial potency of compounds 1 and 2 was assessed against various Gram-positive and Gram-negative bacterial strains and the pathogenic yeast-like Candida albicans. Both compounds showed marked activity against all tested Gram-positive bacteria and weak activity against Escherichia coli and lacked inhibitory activity against Pseudomonas aeruginosa. In addition, compounds 1 and 2 displayed good in vitro anti-proliferative activity against hepatocellular carcinoma (HepG-2) and mammary gland breast cancer (MCF-7) cancer cell lines. Molecular docking studies revealed the binding modes of title compounds at the active sites of prospective therapeutic targets.

Crystal structure of 2-({[5-(adamantan-2-yl)-2-sulfanylidene-1,3,4-oxadiazolidin-3-yl]methyl}amino)benzonitrile, C20H22N4OS

C20H22N4OS, triclinic, P 1 ‾ $P\overline{1}$ (no. 2), a = 6.8528(3) Å, b = 11.3498(5) Å, c = 13.3896(9) Å, α = 114.083(5)°, β = 104.326(4)°, γ = 90.369(3)°, V = 914.38(9) Å3, Z = 2, R gt (F) = 0.0844, wR ref (F 2) = 0.2217, T = 160 K.

Crystal structure of 5-(adamantan-1-yl)-3-[(4-trifluoromethylanilino)methyl]-2,3-dihydro-1,3,4-oxadiazole-2-thione, C20H22F3N3OS

C20H22F3N3OS, triclinic, P1 (no. 1), a = 6.9678(8) Å, b = 10.7614(14) Å, c = 13.0503(14) Å, α = 76.870(3)°, β = 88.004(4)°, γ = 87.275(4)°, V = 951.60(19) Å3, Z = 2, R gt (F) = 0.0629, wR ref (F 2) = 0.1626, T = 100 K.