Triethylamine → (2'-{[Benzyloxycarbonyl-(2,2,2-trifluoro-ethyl)-amino]-methyl}-6-fluoro-4'-trifluoromethyl-biphenyl-3-yl)-acetic acid methyl ester

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Reaction Steps

{6-Fluoro-2′-[(2,2,2-trifluoro-ethylamino)-methyl]-4′-trifluoromethyl-biphenyl-3-yl}-acetic acid methyl ester (0.26 g, 0.62 mmol), benzyl chloroformate (0.13 mL, 0.93 mmol), and triethylamine (0.13 mL, 0.93 mmol) were combined in CH2Cl2 (2.1 mL), and the reaction was stirred at room temperature for 2 hours. Additional benzyl chloroformate (0.13 mL, 0.93 mmol), and triethylamine (0.13 mL, 0.93 mmol) were added, and the reaction was stirred for 1 hour. Starting material was still present, so an aqueous work-up was performed, and the residue was dissolved in DMF and cooled to 0° C. Sodium hydride (60% in mineral oil; 0.030 g, 0.75 mmol) was added, followed by benzyl chloroformate (0.13 mL, 0.93 mmol), and the reaction was stirred for 20 minutes. The mixture was worked up with CH2Cl2 and H2O, and the organic layer was dried over MgSO4, filtered, and concentrated. The residue was purified by silica gel chromatography to give (2′-{[benzyloxycarbonyl-(2,2,2-trifluoro-ethyl)-amino]-methyl}-6-fluoro-4′-trifluoromethyl-biphenyl-3-yl)-acetic acid methyl ester. The ester was hydrolyzed according to the procedure described in Example 17, Step 3.

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