DIASTEREOMERIC OCTAHYDRONAPHTHOQUINOLIZINES

Crystal structures of three diastereoisomers of the ctahydro-4H+,1H,5H -naphtho-[1,2,3-ij]quinolizinium cation, C16H22N + (as the chloride di chloromethane solvate and as two perchlorate salts), C16H22N, are repo rted. The ring junctions B/C, B/D and C/D are cis,cis,trans (1), trans ,trans,trans (2) and cis,trans,cis (3), respectively. In all three iso mers, rings C and D of the quinolizine moiety adopt an almost perfect chair conformation while the fused ring B of the naphtho moiety adopts a half-chair conformation. These structural features are consistent w ith the presence of Bohlmann bands in the IR spectra of (1) and (2), b ut not (3).