5-Phenyl-2-(benzalhydrazonyl)-1,3,4-thiadiazoles, potential trypanocidal agents: consistent dimer formation via N–H · · · N intermolecular hydrogen bonds

Abstract

Abstract The molecular and crystal structures of a series of 5-Ph-2-(arylCH=NNH)-1,3,4-thiadiazoles [2: aryl = 4-XC6H4 (X = H [2a], 4-Cl [2b], 4-Br [2c], 4-F3CO [2d], 2-HO [2e], 2-HO-3-MeO [2f] as well as [5-Ph-2-(4-HOC6H4CH=NNH)-1,3,4-thiadiazole]3(H2O)2] [(2g)3 · 2 (H2O)] are reported. The compounds were prepared as part of a study on typanocide reagents as possible treatments for Chagas‘ disease. The asymmetric unit of [(2g)3 · 2 (H2O)] consists of three independent molecules and two water molecules, in contrast to the single molecules comprising the asymmetric units of 2a–2f. In all cases, N–H · · · N intermolecular hydrogen bonding results in the formation of dimers linked by R2 2(8) rings. As well as the hydrogen-bonded dimers, the molecules of 2a–2f are also linked by other weak interactions including aromatic π–π stacking and C–H · · · X bonds.