S. Arai et al., SYNTHESIS OF NEW AZONIA-HELICENES WITH A QUATERNARY NITROGEN AT THE INNER HELIX SKELETON, Journal of heterocyclic chemistry, 32(3), 1995, pp. 1081-1083
The 16c-azonia[6]helicene salts, in which a carbon atom at the inner h
elix skeleton of [6]helicene is replaced by a quaternary nitrogen atom
, have been synthesized by photo-induced intramolecular quaternization
of 2-[2-(1-chloronaphthyl)vinyl]benzo[h]quinolines in acetonitrile.