Preparation of 8-(5-oxoindeno [3,2-b]-4-pyridyl)-1-naphthoic acids

The condensation of 1-(1,3-indanedion-2-ylidene)-2-acenaphthenone with imines of -dicarbonyl compounds gave 2,5-dioxospiro 1,4,acenaphthene-1,4-dihydroindeno-3,2-b]pyridines. Oxidation of the pyridines with air oxygen at room temperature without catalysts brings about cleavage of the C-C bond to give 8-(5-oxoindeno3,2-b]-4-pyridyl)-1-naphthoic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 210–212, February, 1972.