Syntheses of 9, 9'-Diamino-3, 3'-dibenzanthronyl and 3, 3'-Dibenzanthrony1-9, 9-dicarboxylic Acid

Abstract

As bifunctional derivatives of 3, 3'-dibenzanthronyl, 9, 9'-diamine (1) and 9, 9'-dicarboxylic acid (2) were synthesized for the purpose of preparing new condensation polymers. Compound (1) was prepared as follows. m-Nitrobenzoyl chloride was treated with naphthalene by Friedel-Crafts reaction to give m-nitrophenyl naphtyl ketone (5), mp 125°C, in 30% yield. The ring closure of (5) proceeded at 100°C with a mixture of AlCl3 and NaCl (5:1), then the reaction mixture was treated in the usual method and seperated chromatographically to give 9-nitrobenzanthrone (6) as pale yellow needles, mp 292°C, in 13.3% yield.The dehydrogenation-condensation of (6) was performed under the conditions similar to those for the syntheses of 3, 3'-dibenzanthronyl and its halogen derivatives to give 9, 9'-dinitro-3, 3'-dibenzanthronyl (7), mp>460°C, in 20% yield, which was identified by i.r. spectra and elemental analysis.(8) was reduced by Pd-charcoal and hydrazine hydrate in DMF, to give red violet crystalline powder, mp>500°C, which was identified as (1). (1) was also characterized by comparing with the product obtained by ammonolysis of 9, 9'-dichloro-3, 3'-dibenzanthronyl with 28% aq. ammonia in the presence of As2O5.3, 3'-Dibenzanthronyl-9, 9'-dicarboxylic acid (2), mp 431°C, was synthesized by the oxidation of 9, 9'-dimethyl derivative (16) with KMnO4 in pyridine. The structure of (2) was identified by elemental analysis, i.r. and mass spectrometry. (16) was prepared by the same method as (7), but with shorter reaction time, from 9-methylbenzanthrone (15), as pale yellow needles, mp 3836°C, in 20% yield. Ring closure of 1-naphthyl-m-toluylketone (14) proceeded easily according to Fieser, in 48% yield, but there remained some problems in the synthesis of intermediates, such as m-toluic acid.Partial oxidation of m-xylene is known to give m-toluic acid (12) but in poor yields (less than 10%). We have oxidized m-xylene by dil-HNO3 in the presence of Co salt of naphthenic acid, and obtained (12) (mp 112°C) in 17% yield. Friedel-Crafts condensation of m-toluyl chloride with naphthalene gave (14), mp 75°C, in 33% yield.