Unusual isolation of a hemiaminal product from 4-cyclohexyl-3-thiosemicarbazide and di-2-pyridyl ketone: Structural and spectral investigations

Stable hemiaminal product was isolated as single crystals from the condensation reaction of di-2-pyridyl ketone with 4-cyclohexyl-3-thiosemicarbazide and structurally and spectrochemically characterized. The compound is the first report of a stable hemiaminal product of the condensation reaction of a substituted thiosemicarbazone. Spectral characterization was carried out using IR, UV-vis., 1H NMR, 13C NMR, COSY and HMQC. The compound crystallizes into a triclinic lattice with space group P-1. The molecule reveals a highly strained ZE conformation and a one-dimensional packing is effected by a network of intermolecular hydrogen bonding interactions in the unit cell.