- A 2, 4, 5-trifluorophenylacetic acid method for the preparation of
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The invention discloses a preparation method 2,4,5-trifluorophenylacetic acid. The method is characterized by consisting of four reaction steps of: A, reaction of 2,4,5-trifluoronitrobenzene (I) and diethyl malonate which are condensed to prepare 2,5-difloro-4-nitrobenzophenone diethyl malonate; B, hydrolysis, acidification and decarboxylic reaction of dibasic ester; C, reduction reaction of nitryl; and D, diazotization fluoridation of amino. The four reaction steps can be sequentially carried out according to A, B, C and D, or A, C, B and D, or A, C, D and B. According to the preparation method provided by the invention, condensation of 2,4,5-trifluoronitrobenzene (I) and diethyl malonate is easy to realize by means of high substituting activity of nitryl p-fluorine, and the raw material 2,4,5-trifluoronitrobenzene (I) is low in cost and easy to obtain and can be easily prepared by nitration and fluorination of 2,4-dichlor fluorbenzene. Compared with the prior art, the preparation method provided by the invention has the characteristics of low-cost and easily obtained raw materials, mild reaction condition, high total yield, low production cost and the like, and is comparatively suitable for industrialized production.
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- BENZAMIDE DERIVATIVES AS EP4 RECEPTOR AGONISTS
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A compound of formula (I) or a pharmaceutically acceptable derivative thereof, wherein, R1, R2, R3, R4, R5, m, n and X are as defined in the specification; a process for preparing such compounds; a pharmaceutical composition comprising such compounds; and the use of such compounds in medicine.
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Page/Page column 43
(2008/12/06)
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