Crystal structure of (S)-5,7-diphenyl-4,7-dihydrotetrazolo[1,5-a]pyrimidine

The title compound, C16H13N5, was synthesized by coupling aminotetrazole with chalcone in the presence of an amine organocatalyst derived from chincona alkaloid. There are two molecules, A and B, in the asymmetric unit. In molecule A, the dihedral angles between the partly hydrogenated pyrimidine ring system (r.m.s. deviation = 0.056 angstrom) and the sp(2)- and sp(3)-bonded phenyl groups are 33.32 (11) and 86.53 (11), respectively. The equivalent data for molecule B are 0.049 A, and 27.05 (10) and 85.27 (11), respectively. In the crystal, A+B dimers linked by pairs of N-H center dot center dot center dot N hydrogen bonds generate R-2(2)(8) loops. The dimers are linked by aromatic pi-pi stacking interactions [shortest centroid centroid separation = 3.5367 (15) angstrom], which results in a three-dimensional network.