1: With trifluoroacetic anhydride in benzene T=20°C; Pummerer reaction; 0.5 h; 2: With boron trifluoride diethyl etherate in benzene T=20°C; Pummerer reaction; 24 h;

1.1: TFAA / benzene / 0.5 h / 20 °C 1.2: 13 percent / BF3*Et2O / benzene / 24 h / 20 °C 2.1: 67 percent / p-TsOH*H2O / toluene / 19 h / Heating View Scheme

1: With trifluoroacetic anhydride in benzene T=20°C; Pummerer reaction; 0.5 h; 2: With boron trifluoride diethyl etherate in benzene T=20°C; Pummerer reaction; 24 h;