potassium hydrogencarbonate in N,N-dimethyl-formamide 3 h; Ambient temperature;

1: 0 °C 2: triethylamine, ethyl chloroformate / CHCl3 / 3.5 h / Ambient temperature 3: 1.) sodium hydride / 1.) THF, RT, 1 h, 2.) THF, RT, 1 h 4: 70 percent / potassium bicarbonate / dimethylformamide / 3 h / Ambient temperature View Scheme

1: 1.) sodium hydride / 1.) THF, RT, 1 h, 2.) THF, RT, 1 h 2: 70 percent / potassium bicarbonate / dimethylformamide / 3 h / Ambient temperature View Scheme

PPA T=120°C; 2 h;