The hydro­chloride salt of l-ecgonine, a congener of cocaine

The title compound, (1R,2R,3S,5S,8S)-3-hydr-oxy-8-methyl-8-azoniabicyclo-[3.2.1]octane-2-carboxylic acid chloride, C(9)H(16)NO(3) (+)·Cl(-), is both a metabolite and a precursor of the tropane alkaloid l-cocaine. The carboxyl group is not involved in dimerization, but instead donates a hydrogen bond to the chloride counter-ion, which participates in two additional hydrogen bonds. The chloride ion is thus trigonally hydrogen bonded to three l-ecgonine cations. The quarternary N proton is intra-molecularly hydrogen bonded to the carboxyl C=O group, an arrangement identical to that reported for both (-)-nor-cocaine and the tetrachloroaurate(III) salt of l-cocaine. One close inter-molecular C-H⋯O contact exists.