Synthesis, stereochemical, structural and biological studies of some 2,6-diarylpiperidin-4-one N(4′)-cyclohexyl thiosemicarbazones

A new series of 2,6-diarylpiperidin-4-one N(4′)-cyclohexyl thiosemicarbazones (13-23) were synthesized by corresponding 2,6-diarylpiperidin-4-ones (1-11) reaction with cyclohexyl thiosemicarbazide (12). The chemical structures were confirmed by means of IR, one and two dimensional NMR, Mass spectra and single crystal X-ray diffraction analysis. Compounds 13-23, exist in chair conformation with equatorial orientation of all the substituents at piperidine ring except the methyl group at C-5 of compounds 21-23 oriented at axial disposition to stabilize the chair conformation. Single crystal X-ray structural analysis of compound 18, evidences that the configuration about CN double bond is syn to C-5 carbon (E-form). All the synthesized compounds were screened their biological activity.