title: Crystal structure of 3-[(4-benzyl-piperazin-1-yl)meth-yl]-5-(thio-phen-2-yl)-2,3-di-hydro-1,3,4-oxa-diazole-2-thione.
abstract: The title 1,3,4-oxa-diazole-2-thione derivative, C18H20N4OS2, crystallized with two independent mol-ecules (A and B) in the asymmetric unit. The 2-thienyl rings in both mol-ecules are rotationally disordered over two orientations by approximately 180° about the single C-C bond that connects it to the oxa-diazole 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 mol-ecules A and B, respectively. The 1,3,4-oxa-diazole-2-thione ring forms dihedral angles of 7.71 (16), 10.0 (11) and 77.50 (12)° (mol-ecule A), and 6.5 (3), 6.0 (9) and 55.30 (12)° (mol-ecule B) with the major and minor parts of the disordered thio-phene ring and the mean plane of the adjacent piperazine ring, respectively, resulting in approximately V-shaped conformations for the mol-ecules. The piperazine ring in both mol-ecules 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 mol-ecules A and B, respectively. In the crystal, no inter-molecular hydrogen bonds are observed. The crystal packing features short S⋯S contacts [3.4792 (9) Å] and π-π inter-actions [3.661 (3), 3.664 (11) and 3.5727 (10) Å], producing a three-dimensional network.
authors.affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, PO Box 2457, Riaydh 11451, Saudi Arabia.
authors.forename: Fatmah A M
authors.initials: FA
authors.lastname: Al-Omary
authors.affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, PO Box 2457, Riaydh 11451, Saudi Arabia ; King Abdullah Institute for Nanotechnology (KAIN), King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Ali A
authors.initials: AA
authors.lastname: El-Emam
authors.affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Hazem A
authors.initials: HA
authors.lastname: Ghabbour
authors.affiliation: X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia ; Department of Chemistry, Alva's Institute of Engineering & Technology, Mijar, Moodbidri 574 225, Karnataka, India.
authors.forename: C S
authors.initials: CS
authors.lastname: Chidan Kumar
authors.affiliation: X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
authors.forename: Ching Kheng
authors.initials: CK
authors.lastname: Quah
authors.affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, PO Box 2457, Riaydh 11451, Saudi Arabia ; X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
authors.forename: Hoong-Kun
authors.initials: HK
authors.lastname: Fun
keywords: 1,3,4-oxa­diazole; S⋯S contacts; crystal structure; disorder; piperazin-1-yl; π–π inter­actions
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