Pyrido[2,3-g]quinolines

The heretofore unknown sym-octahydro-4,9-dioxopyrido2,3-g]quinoline was synthesized by carboxyethylation of dimethyl 2,5-diaminoterephthalate with -propiolactone with subsequent hydrolysis of the resulting 2,5-bis(-carboxyethylamino)terephthalic acid ester and cyclization of 2,5-bis(-carboxyethylamino)terephthalic acid. The structure of the product was confirmed by the UV and IR spectra and also by reduction to the known sym-octahydropyrido 2,3-g]quinoline.See 7] for preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1535–1537, November, 1970.