Naphthylaminomethylenemalonates and Related Ring Systems

Heeramaneck and Shah obtained 3-phenylbenzo[/]quinoline-2-carbox-ylate (908) in good yield on the ring closure of diethyl phenyl(2-naphthyla-mino)methylenemalonate by heating in the melt at 185-195°C (37JCS867). 

The ring closure of N-ethyl-Af-(2-naphthyl)-aminomethylenemalonate by treatment with an equal amount of phosphorus pentoxide at 130°C 

The cyclization of 2-anthranylaminomethylenemalonate by heating in diphenyl ether gave naphtho[2,1 -/]quinolinecarboxylate (910) in 96% yield (62MI2). 

On the cyclization of 2-naphthoquinonylaminomethylenemalonate (911) in boiling diphenyl ether, an insoluble product was obtained (59M12). 

3-Naphthostyrilylaminomethylenemalonate (912) was heated at 250°C to give a tetracyclic compound (913) in almost quantitative yield (39JA2890). 

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