One-Pot Synthesis of Imidazophenanthridinium Salts
A. D. C. Parenty, K. M. Guthrie, Y.-F. Song, L. V. Smith, E. Burkholder, L. Cronin*
University of Glasgow, UK
19 May 2006 (online)
The synthesis of a new class of heterocyclic aromatic cations by a new method is reported. The imidazophenanthridine intermediate, derived by an ammonolysis, cyclization, and oxidation sequence, is quaternized with a wide range of electrophiles to give the imidazophenanthridinium (IP) salts. The IP products show physical properties consistent with stable radical species. The X-ray crystal structure of imidazophenanthridine shows a π-π interaction in the solid state and an increased planarity with electron delocalization over the entire heterocylic framework.