Abstract
Naphthalene-1, 2, 4, 5-and 1, 2, 6, 7-tetracarboxylic acid has been synthesized by oxidation of 1-keto-1, 2, 3, 4-tetrahydro-8, 9-acephenanthrene (6) and 6, 7-dimethylnaphthalene-1, 2-dicarboxylic acid in aqueous sodium bichromate. (6) was prepared by Huang-Minlon reduction of β- (5-acenaphthoyl) propionic acid (4) to give γ- (5-acenaphthyl) butyric acid (5), and then cyclization in polyphosphoric acid. (10) was synthesized by condensation of ethyl γ- (3, 4-dimethylphenyl) butyrate with diethyl oxalate to α-keto-β-ethoxycarbonyl-δ- (3, 4-dimethylphenyl) valeric acid (8) in the presence of sodium ethoxide, followed by the cyclization of (8) with sulfuric acid to 6, 7-dimethy1-3, 4-dihydronaphthalene-1, 2-dicarboxylic anhydride (9) and then dehydrogenation of (9) with sulfur.
