Synthesis of Methylcytisine 9-Thiocarboxamides

Abstract

9-Carboxamide derivatives of the quinolizidine alkaloid methylcytisine were synthesized. The synthetic pathway included nitration-reduction according to the literature that resulted in 9-amination of the 2-pyridone core of the starting alkaloid. The obtained 9-amino derivative was converted by CS2 in Py in the presence of dicyclohexylcarbodiimide (DCC) into the corresponding isothiocyanate. The synthesized 9-isothio derivative was reacted with primary and secondary amines. The yields of the obtained 9-thiocarboxamide methylcytisine derivatives were 80–98%. The structures of the synthesized compounds were established using elemental analyses and IR, PMR, 13C NMR, and 15N NMR spectroscopy.