Synthesis of 6-Acylmethylphenanthridine Enaminones

A series of 6-acylmethylphenanthridine derivatives were synthesized by reaction of aliphatic and aromatic esters with 6-methylphenanthridine in the presence of phenyllithium. Enaminone form of the obtained compounds was investigated by spectroscopic methods. The results revealed that the presence of aromatic rings on 3- and 4-position of 2-acylmethylquinolines (6-acylmethylphenanthridines) is the most important factor for the preference of the enaminone form b. It was found that the intramolecular hydrogen bonding is the only factor that can damage aromaticity of the phenanthridine moiety