Structural features of N-acylcytisines

N-Acyl cytisine derivatives were synthesized by acylation with acetic anhydride; benzoyl and o-bromo- and p-nitrobenzoyl chlorides; and crotonyl and cinnamoyl chlorides. The structures of the synthesized compounds were studied using IR, PMR, and x-ray structure analysis (XSA). PMR spectra of the N-acylcytisines in solution typically had two rotational isomers around the N12-CO bond. Conformational analysis was performed using XSA for the position of the acyl group relative to the cytisine core. Bond lengths and angles of the acyl groups involved in the conjugation were analyzed.