3-tribromoacetic benzoic acid or its ester of manufacturing method

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PROBLEM TO BE SOLVED : To obtain a new 3-bromobenzoic acid derivative used as an intermediate for medicines, agrochemicals, etc., and especially useful as an intermediate for a fluoroquinoline-based synthetic antimicrobial agent. SOLUTION : This derivative is shown by the formula (X1 and X2 are each a halogen; R is H or a 1-6C alkyl), for example, methyl 3-bromo-2, 4-difluoro-5- nitrobenzoate. The compound of the formula is obtained by bromination of a 2, 4-dihalogeno-5-nitrobenzoic acid derivative with a bromate as a bromine source in an equivalent amount of preferably 1.0-3 times that of an aromatic compound of a raw material in 70-100 wt.% sulfric acid at preferably -20 to 100 deg.C for 0.1-10 hrs. A 2, 4-dihalogeno-5-nitrobenzoic acid derivative as a starting material can be obtained by nitration of a 2, 4-dihalogenobenzoic acid derivative, etc. An alkali metal bromate such as potassium bromate or sodium bromate or an alkaline earth metal bromate can be used as the bromate.