3-(Adamantan-1-yl)-1-[(4-benzylpiperazin-1-yl)methyl]-4-[(E)-(2-hydroxybenzylidene)amino]-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C31H38N6OS, the conformation about the N=C [1.285 (2) Å] imine bond is E. The piperazine ring has a chair conformation and occupies a position almost perpendicular to the plane through the triazole ring; the benzene ring forms a dihedral angle of 31.95 (10)° with the triazole ring. Overall, the molecule has the shape of a flattened bowl. The hydroxy group is disordered over two positions. The major component has a site-occupancy factor of 0.762 (3) and forms an intramolecular O—H⋯N(imine) bond to close an S(6) loop. The minor component of the disordered hydroxy group forms an O—H⋯N(piperazine) hydrogen bond. These, along with C—H⋯S and C—H⋯N interactions, link molecules into a three-dimensional architecture.

The financial support of the Deanship of Scientific Research and the Research Center of the College of Pharmacy, King Saud University, is greatly appreciated. The authors also thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR/MOHE/SC/12). supplementary materials Acta Cryst. (2012). E68, o1766-o1767 [doi:10.1107/S1600536812021204]

T. Tiekink Comment
Derivatives of adamantane have long been known for their diverse biological activities including anti-viral activity against the influenza (Vernier et al., 1969) and HIV viruses (El-Emam et al., 2004). Moreover, adamantane derivatives were reported to exhibit marked anti-bacterial and anti-inflammatory activities (Kadi et al., 2007;Kadi et al., 2010). In continuation of our interest in the chemical and pharmacological properties of adamantane derivatives, and as part of ongoing structural studies (Kadi et al., 2011;El-Emam et al., 2012), we synthesized the title compound (I) as a potential chemotherapeutic agent. Herein, we describe the crystal and molecular structure of (I).
In (I), Fig. 1, the conformation about the N1═C25 [1.285 (2) Å] imine bond is E. The piperazinyl ring, having a chair conformation, projects almost normal to the plane through the triazole ring (r.m.s. deviation = 0.014 Å) as seen in the value of the N3-N4-C13-N5 torsion angle = -67.3 (2)°. By contrast, the benzene ring is splayed with respect to the triazole ring with the C25-N1-N2-C11 torsion angle being -153.92 (17)°; the dihedral angle between the rings is 31.95 (10)°. Overall, the molecule has the shape of a flattened bowl. As noted below, the hydroxy group is disordered over two positions. The major component is aligned to allow the formation of an intramolecular O-H···N(imine) bond to close an S(6) loop,

Refinement
The H-atoms were placed in calculated positions [O-H = 0.84 Å and C-H = 0.95 to 1.00 Å, U iso (H) = 1.2-1.5U eq (O,C)] and were included in the refinement in the riding model approximation. The hydroxy group was disordered over two positions. Each component was refined independently and the major component has a site occupancy factor = 0.762 (3).
A reflection, i.e. (12 2 8), was omitted from the final cycles of refinement owing to poor agreement.

Figure 1
The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.   Special details Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.