2,3,4-Trifluorobenzoic acid → 3,4-Difluoro-2-[[2-fluoro-4-(methylthio)phenyl]amino]benzoic acid

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Reaction Steps

2,3,4-Trifluorobenzoic acid and the product of Example 26, Step B, 2-fluoro-4-methylthioaniline, were reacted in the presence of LiHMDS solution in THF by the general procedure of Example 1, Step B. After workup, this material was purified by dry flash column chromatography on silica (0.5% Et2O in 1:1 CH2Cl2/hexanes as eluant) to afford 3,4-difluoro-2-[[2-fluoro-4-(methylthio)phenyl]amino]benzoic acid as a cream solid (52%); m.p. (Et2O/hexanes) 210–220° C. 1H NMR (400 MHz, CDCl3) δ 13.70 (br s, 1 H), 9.24 (br s, 1 H), 7.81 (ddd, J=9.0, 6.1, 2.1 Hz, 1 H), 7.20 (dd, J=11.8, 1.9 Hz, 1 H), 7.03–6.99 (m, 3 H), 2.47 (s, 3 H). Anal. Calcd for C14H10F3NO2S.0.125 Et2O: C, 54.0; H, 3.5; N, 4.3. Found: C, 54.2; H, 3.3; N, 4.5.

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