Molecular and crystal structure ofβ-isosparteine monoperchlorate

Abstract

The crystal structure; determined by X rays, and the¹³C-NMR spectra ofβ-isosparteine perchlorate are presented. The quinolizidine moieties are present in acis ring-juncture; all piperidine rings are in a chair conformation. The two nitrogen atoms are linked by a hydrogen bond of 2.704(5) Å. The proton at N(16) is also involved in a weak hydrogen bond with the O(2) of the perchlorate anion. The two quinolizidine moieties-protonated and unprotonated-differ only slightly in conformation; the protonation caused small but significant changes in the length of the bonds about the nitrogen atoms. The title compound was obtained by chemical transformations of 17-oxosparteine and protonation with an equimolar amount of HClO₄ in methanol.¹³C-NMR spectra in DMSO-²H₆ revealed the presence of the symmetricalcis-cis bis-quinolizidine structure of the salt in solution.