Oxalyl chloride → 2-Ethoxybenzoyl chloride

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A solution of 2-ethoxybenzoic acid (0.75 g, 4.5 mmol) in 23 mL of methylene chloride at 0° C. was treated with oxalyl chloride (0.44 mL, 4.9 mmol) followed by 2 drops of dimethylformamide. The solution was stirred at ambient temperature for 1 hour and then concentrated under reduced pressure to provide 0.83 g of 2-ethoxybenzoyl chloride. To a solution of 4-trifluoromethylthiazol-2-ylamine (0.50 g, 3.0 mmol) in 10 mL THF at 0° C. was added a solution of the freshly prepared acid chloride in 5 mL of THF and 2 mL of methylene chloride, followed by triethylamine (1.0 mL, 6.6 mmol). The reaction mixture was warmed to 65° C. and stirred 8 hours. The mixture was diluted with ethyl acetate and washed twice with water, then brine. The organic extract was dried over magnesium sulfate, filtered, and concentrated under reduced pressure. Purification by column chromatography (SiO2, 30-50% ethyl acetate/hexanes gradient) afforded 0.47 g (50%) of the title compound. 1H NMR (CDCl3, 300 MHz) δ ppm 1.66 (t, J=6.95 Hz, 3H), 4.38 (q, J=6.89 Hz, 2H), 7.03-7.10 (m, 2H), 7.17 (d, J=7.80 Hz, 1H), 7.42 (s, 1H), 8.29 (dd, J=7.97, 1.86 Hz, 1H). MS (DCI/NH3) m/z 317 (M+H)+.

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