1. (4S)-4-Benzyl-N-{[(4S)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]sulfon-yl}-2-oxo-1,3-oxazolidine-3-carboxamide
Malika Berredjem, Assia Allaoui, Amani Direm, Noureddine Aouf, Nourredine Benali-Cherif Acta Crystallogr Sect E Struct Rep Online. 2010 Jun 9;66(Pt 7):o1611-2. doi: 10.1107/S1600536810020866.
The title compound, C(21)H(21)N(3)O(7)S, contains an oxazolidinone ring and a sulfonamide group, both characteristic for biologically and pharrmaceutically active compounds. Both stereogenic centres reveal an S absolute configuration. The two oxazolidinone rings are in an envelope conformation with the methyl-ene carbon flap atoms deviating by 0.428 (1) and 0.364 (2) Å from the best least-square planes formed by the four other ring atoms. An intra-molecular N-H⋯O hydrogen bond contributes to the folded conformation of the mol-ecule. In the crystal, weak inter-molecular C-H⋯O inter-actions connect the mol-ecules into helices along the the twofold screw axes.
2. N-[(2Z,4Z)-4-Benzyl-idene-6-chloro-1,4-dihydro-pyrido[2,3-d][1,3]thia-zin-2-yl-idene]benzamide
Manuel A Fernandes, Demetrius C Levendis, David H Reid Acta Crystallogr Sect E Struct Rep Online. 2012 Aug 1;68(Pt 8):o2346. doi: 10.1107/S1600536812029741. Epub 2012 Jul 7.
In the crystal structure of the title compound, C(21)H(14)ClN(3)OS, mol-ecules assemble into inversion dimers via pairs of N-H⋯N hydrogen bonds involving the N-H hydrogen of the thia-zine ring and the N atom of the pyridine ring. There is a close intra-molecular contact [2.570 (2) Å] between the carbonyl O atom of the benzamide and the S atom of the puckered thia-zine ring. The title compound can exist in two tautomeric forms, viz. amino or imino. The observed structure is compatible with the imino form on the basis of observed residual electron density and the two C-N bond lengths of 1.308 (2) and 1.353 (2) Å.
3. 4-Benzyl-N-methyl-piperazine-1-carbothio-amide
Amer M Alanazi, Ali A El-Emam, Nasser R El-Brollosy, Seik Weng Ng, Edward R T Tiekink Acta Crystallogr Sect E Struct Rep Online. 2012 Mar 1;68(Pt 3):o712-3. doi: 10.1107/S1600536812005685. Epub 2012 Feb 17.
The asymmetric unit in the title thio-urea derivative, C(13)H(19)N(3)S, comprises three independent mol-ecules (A, B and C). The thio-urea groups are superimposable for the three mol-ecules, but there are significant conformational differences. Mol-ecules A and B are approximate mirror images of each other, and mol-ecule C has an inter-mediate conformation. The dihedral angles between the thio-urea groups and the phenyl rings are 52.10 (5), 63.29 (5) and 66.46 (6)° in mol-ecules A, B and C, respectively. Each independent mol-ecule self-associates into a supra-molecular chain along [100] via N-H⋯S hydrogen bonds. Mol-ecules of A and B assemble into layers four mol-ecules thick in the ac plane via C-H⋯S and C-H⋯π inter-actions. Mol-ecules of C self-assemble into layers in the ac plane via C-H⋯S inter-actions. The layers stack along the b axis with no specific inter-actions between them.
