[F:1][C:2]1[CH:3]=[C:4](N)[C:5](=[CH:9][C:10]=1[F:11])[C:6]([OH:8])=[O:7].FC1C=C2C(=O)OC(=O)C2=CC=1F.FC1C=C(C(O)=O)C(=CC=1F)C(O)=O>FC1C=C2C(=O)OC(=O)C2=CC=1F.FC1C=C(C(O)=O)C(=CC=1F)C(O)=O.CN1CCCC1=O.N1C2C(=CC=CC=2)C=CC=1.CC(N(C)C)=O.[Cu].[Cu]=O.[Zn].[Ni]>[F:11][C:10]1[CH:9]=[C:5]([CH:4]=[CH:3][C:2]=1[F:1])[C:6]([OH:8])=[O:7]
According to the present invention, 4,5-difluoroanthranilic acid may be prepared from either 4,5 difluorophthalic anhydride or 4,5-difluorophthalic acid. The process of this invention comprises the decarboxylation of either 4,5-difluorophthalic anhydride and 4,5-difluorophthalic acid in N-methyl-2-pyrrolidone, quinoline, or dimethyl acetamide solution optionally using copper, copper oxide, copper salts, or halides and salts of Zn, Cd, Ag and Ni as a catalyst, to yield 3,4-difluorobenzoic acid; the nitration of the 3,4-difluorobenzoic acid in a mixture of nitric and sulfuric acids to form 2-nitro-4,5-difluorobenzoic acid; and the reduction of the 2-nitro-4,5-difluorobenzoic acid to form 4,5-difluoroanthranilic acid.
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