Trifluoroacetamide

383-63-1

354-38-1

Example 5: Synthesis of the blocking isomer trifluoroacetamide 3a The block trans isomer 2a (0.93 g, 1.84 mmol, 503.4 g/mol) as a sulfate was dissolved in 15 mL of ethanol. Under argon protection, triethylamine (1.8 mL, 13 mmol) and ethyl trifluoroacetate (2.2 mL, 18 mmol) were slowly added (Figure 2a). The reaction mixture was stirred for 2.5 h at room temperature. Upon completion of the reaction, the volatiles were removed by distillation under reduced pressure. The resulting residue was dissolved in 300 mL of ethyl acetate and washed sequentially with 2 x 50 mL of 5% hydrochloric acid solution. The organic phase was dried with anhydrous Na2SO4, filtered and concentrated under reduced pressure to afford block-transfer isomerized trifluoroacetamide 3a as an orange solid (0.92 g, 100% yield, 501.4 g/mol). 1H NMR (methanol-d4) δ 8.35 (1H, d); 8.15 (1H, d); 7.80 (1H, s); 6.82 (1H, s); 6.65 (4H, m); 4.82 (2H, s).