potassium carbonate in acetone 5 h; Heating;

1: 55 percent / NaN3 / dimethylformamide / 24 h / Ambient temperature 2: 67 percent / HBr(g), phenol, 99percent AcOH / 1.5 h / 80 °C 3: 60 percent / K2CO3 / acetone / 5 h / Heating View Scheme