Addition reactions of heterocyclic compounds. Part XXVIII. The synthesis of phenanthridinium-5-vinyloxides and pyrrolo[1,2-f]phenanthridines

Abstract

Dimethyl acetylenedicarboxylate and other acetylenic esters add to phenanthridine 5-oxides to give phenanthridinium-5-vinyloxides, which, if a 6-alkyl group is present, readily cyclise to methoxycarbonylpyrrolo[1,2-f]-phenanthridines. Hydrolysis and decarboxylation give pyrrolo[1,2-f]phenanthridine and derivatives. The nuclear magnetic resonance spectra of these compounds have been partially analysed.