Example 163 STR185 Step 1. Preparation of N-(4-trifluoromethylphenyl)-2,2-dimethylpropionamide. Dichloromethane (200 mL), 4-aminobenzotrifluoride (32.0 g, 199 mmol), and triethylamine (40 g, 396 mmol) were added to a reaction flask under dry nitrogen protection, and the mixture was cooled to 0°C. Trimethylacetyl chloride (32.9 g, 273 mmol) was slowly added dropwise over a period of 2 hours, controlling the reaction temperature to no more than 10°C. The reaction temperature was then adjusted to the temperature of the reaction. After the dropwise addition, the reaction mixture was gradually warmed up to room temperature and stirring was continued for 2 hours. After the reaction was completed, the reaction mixture was washed with water (2×200 mL) and saturated ammonium chloride solution (2×200 mL) sequentially, and the organic phase was dried over anhydrous sodium sulfate and filtered. The solvent was removed by distillation under reduced pressure to afford N-(4-trifluoromethylphenyl)-2,2-dimethylpropionamide (48.0 g, 98% yield) as a white solid: melting point 157-159 °C. 1H NMR (CDCl3, 300 MHz) δ 7.61 (ab, 4H, J = 8.7 Hz, Δν= 28.6 Hz), 7.47 (br s, 1H), 1.33 (s, 9H).ESHRMS m/z 246.1123 ([M + H]+, calculated value 246.1106). Elemental analysis (C12H14F3NO) Calculated values: C, 58.77; H, 5.75; N, 5.71. measured values: C, 58.28; H, 5.79; N, 5.65.
