Synthesis and crystal structure of N-ethyl-N-cytisinocarbothioamide

Abstract

Based on (–)-cytisine alkaloid and ethyl isothiocyanate, N-ethyl-N-cytisinocarbothioamide is synthesized and its structure is proved by 1H NMR spectroscopy and single crystal X-ray diffraction. The mesomeric effect is shown in the carbothioamide group formed. It is found that π-conjugation between nitrogen atoms and the thiocarbonyl group is weakened due to the steric hindrance between hydrogen atoms of the piperidine ring and the thioamide group.