Synthesis of heterocyclic compounds. Part XXX. Reactions of o-alkylamino- and o-dialkylamino-anilines with some αβ-unsaturated carbonyl compounds

Abstract

The condensation of o-alkylamino- and o-dialkylamino-anilines with diethyl ethoxymethylenemalonate gave intermediates which could be cyclised to 4-quinolone derivatives. In phosphoryl chloride, the intermediate from N-(o-aminophenyl)pyrrole gave pyrrolo[1,2-a]quinoxaline. 4-Quinolones were also prepared by the reaction of o-dialkylaminoanilines with dimethyl acetylenedicarboxylate, followed by thermal cyclisation. The intermediate from N-(o-aminophenyl)pyrrole gave a pyrrolo[1,2-a]quinoxaline derivative. o-Dialkylaminoanilines attacked the β-carbon atom of methyl acrylate but the resulting intermediates could not be cyclised. The corresponding reactions with methyl methacrylate and methyl crotonate gave amides, via attack at the ester carbonyl group. With acetylacetone, the intermediate imine was formed, but failed to cyclise in polyphosphoric acid or its ethyl ester.