Synthesis Of Phthalic Acids Containing Quinone Groups

The catalytic oxidation of hydrocarbon under mild conditions has a very high application value. C-H could be functionalized by molecular O2using N-hydroxyphthalimide (NHPI) as catalyst. This kind of the reaction caused the people’s attention due to the advantages of good selectivity, widespread applicability and higher conversion. The better catalytic effect could be getten using NHPI cooperated with transition metal salts or radical initiators, but creates the cost and environmental problems. Using quinones via intermolecular electronic transfer could promote the oxidation of hydrocarbon compound catalyzed by NHPI and aviod the problems mentioned above.We assumed that NHPI and quinones were connected by means of chemical bond, then a new one-component catalyst was synthetized and could show the unique catalytic performance by intramolecular proton coupling electronic transfer. So the catalysts4-(2-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-N-hydroxyphthalimideand4-(9,10-anthraquinone-2-yl)-N-hydroxyphthalimide were designed. In this paper the major research direction was the synthesis of the key intermedium of catalyst-phthalic acids containing quinone groups.Firstly, the diazonium salt of4-aminophthalic acid without water was prepared by diazotization reaction, then reacted with2-chlorine-1,4-naphthoquinone via Meerwein reaction to get a key intermediate4-(2-chlorine-1,4-naphthoquinone-2-yl-)-phthalic acid (CNQPA)which was no literature reported. The yield was90%, and this key intermediate was characterized by1HNMR and13CNMR. Meanwhile, using the intermediates the synthesis of NCQNHPI catalyst was researched through the anhydride method, acyl halide method and lipid amidation method, but the NCQNHPI catalyst could not be obtained because of the naphthalene quinone ring and activity of chlorine substituent effect.During the synthsis of2-AQNHPI, on one hand, the Gomberg-Bachmann reaction of anthraquinone were studied, on the other hand, the intermediates2-(3,4-dimethylphenyl)-9,10-anthraquinone (DMPAQ) and4-(9,10-anthraquinone-2-yl)phthalic acid (AQPA), which were no literature reported, were prepared. The reaction of diethyl4-aminophthalate as meterial and aromatic compounds via Gomberg-Bachmann reaction was occurred to form biphenyl-3,4-dicarboxylic acid and3’,4’-dimethylbiphenyl-3,4-dicarboxylic acid, which was then reacted via F-C reaction catalyzed by AlCl3, cyclization reaction and oxidation to genetate DMPAQ and AQPA. The single acylation product was obtained by controling the Friedel-Crafts alkylation selectivity using3,3’,4,4’-Biphenyl tetracarboxylic diandhydride as raw material. Then the further product4-(6-chloro-9,10-anthraquinone-2-yl)-diethyl phthalate (CAQDEP) was generated by the cyclization reaction and esterification reaction of the single acylation product. These synthetic steps was a basis of the synthesis of latter catalyst.