Crystal structure of 3-[(4-benzylpiperazin-1-yl)methyl]-5-(thiophen-2-yl)-2,3-dihydro-1,3,4-oxadiazole-2-thione

Abstract

The title 1,3,4-oxadiazole-2-thione derivative, C18H20N4OS2, crystallized with two independent molecules (AandB) in the asymmetric unit. The 2-thienyl rings in both molecules are rotationally disordered over two orientations by approximately 180° about the single C—C bond that connects it to the oxadiazole thione ring; the ratios of site occupancies for the major and minor components were fixed in the structure refinement at 0.8:0.2 and 0.9:0.1 in moleculesAandB, respectively. The 1,3,4-oxadiazole-2-thione ring forms dihedral angles of 7.71 (16), 10.0 (11) and 77.50 (12)° (moleculeA), and 6.5 (3), 6.0 (9) and 55.30 (12)° (moleculeB) with the major and minor parts of the disordered thiophene ring and the mean plane of the adjacent piperazine ring, respectively, resulting in approximately V-shaped conformations for the molecules. The piperazine ring in both molecules adopts a chair conformation. The terminal benzene ring is inclined towards the mean plane of the piperazine ring with N—C—C—C torsion angles of −58.2 (3) and −66.2 (3)° in moleculesAandB, respectively. In the crystal, no intermolecular hydrogen bonds are observed. The crystal packing features short S...S contacts [3.4792 (9) Å] and π–π interactions [3.661 (3), 3.664 (11) and 3.5727 (10) Å], producing a three-dimensional network.