Abstract:

The synthetic method of a new aromatic diacid, 9,9-bis[4-(4-carboxyphenoxy)phenyl]xanthene(4) was developed from the reaction of 9,9-bis(4-hydroxyphenyl)xanthene(1) with 4-methyl-1-iodobenzene(2) by means of the Ullmann coupling and oxidation reaction successively. The treatment of compound 1 with compound 2 in DMF in the presence of cuprous iodide/tetrabutylammonium bromide/potassium phosphate at reflux temperature for 24 h afforded 9,9-bis[4-(4-methylphenoxy)phenyl]xanthene(3) in 95% yield. The compound 3 was then oxidized to the corresponding aromatic, 9,9-bis[4-(4-carboxyphenoxy)phenyl]xanthene(4) in 84% yield directly using oxygen in the presence of a catalytic amount of N-bromosuccinimde(NBS) under photoirradiation. The new diacid 4 was obtained in an overall yield of about 79.8%(based on compound 1). The structure of the target compound was characterized by 1H NMR, 13C NMR, IR and elemental analysis. The present method has the advantage of convenient availability of starting materials, mild reaction conditions, convenient manipulation and good yield.

Key words: bis[(carboxyphenoxy)phenyl]xanthene, bis(hydroxyphenyl)xanthene, methyliodobenzene, Ullmann reaction, oxidation reaction