Preparation of 5, 6, 7, 8-Tetrafluoro-2, 4-quinolinediol and Some Azo Colors Derived Therefrom

Abstract

5, 6, 7, 8-Tetrafluoro-2, 4-quinolinediol [4] has been prepared in ca.30% yield by the inframolecular condensation of methyl N-acetyltetrafluoroanthranilate [3] by means of sodium in boiling toluene. Another possible route to [4] which involves the fusion of malonyl bis(tetrafluoroanilide) [7] with a mixture of aluminum chloride and sodium chloride gave only a product in which fluorines were partially replaced by chlorine. Four yellow azo colors were prepared by coupling diazotized aniline or m-substituted anilines with [4]. The visible absorption spectra of these colors were compared with those of the corresponding fluorine-free colors (Table 1 and Fig.1, 2). The tetrafluoro colors using aniline or toluidine as diazo component showed batho- and hyperchromic effect. On the contrary, the electronegative chloro or nitro group in the diazo component shifted the absorption hypochromically. No improvement in light fastness was observed by the introduction of fluorines into color molecules.