Nucleophilic displacements of N ‐aryl and heteroaryl groups. Part 8 . Intermolecular reactions of N ‐aryl‐pyridinium, ‐quinolinium, and ‐acridinium salts with nucleophiles

N ‐Aryl‐mono‐, ‐tri‐ and ‐pentacyclic pyridinium cations react with S ‐ and C‐nucleophiles to give: (i) simple addition of hydride at the α‐ring position, (ii) nucleophilic addition of thiophenoxide at the γ‐ring position, (iii) deprotonation at the 6‐position of a 5,6‐dihydroquinolinium ring followed by prototropic shift to give a 1,2‐dihydroquinoline derivative, (iv) ring contraction of a pyridine to a pyrrole ring, and (v) nucleophilic displacement of the N ‐aryl group.