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A new synthesis of dibenzo[ b,g ][1,5]naphthyridine‐6,12(5 H ,1 H )dione (epindolidione)
Author(s) -
Kim C. K.,
Maggiulli C. A.
Publication year - 1979
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570160829
Subject(s) - chemistry , yield (engineering) , aniline , boiling , condensation , catalysis , derivative (finance) , medicinal chemistry , solvent , ring (chemistry) , organic chemistry , materials science , physics , economics , financial economics , metallurgy , thermodynamics
A new convenient synthesis of dibenzo[ b,g ][1,5]naphthyridine‐6,12(5 H ,11 H )dione starting from N ‐phenylglycine ethyl ester is described. Ester condensation of N ‐phenylglycine ethyl ester with diethyl oxalate followed by reaction with aniline under acid catalysis gave a mixture of diethyl dianilinomaleate and diethyl dianilinofumarate in 54% yield. Upon heating this mixture in a high‐boiling inert solvent, 3‐anilino‐2‐ethoxycarbonyl‐4‐quinolone was obtained in 72% yield. Final ring closure of the quinolone derivative using polyphosphoric acid gave the epindolidione.