1: oxalyl chloride / CH2Cl2 / 3.5 h / Ambient temperature 2: NaN3 / dimethylformamide; CH2Cl2; H2O / 1.5 h / 0 °C 3: toluene / Heating View Scheme

1: NaN3 / dimethylformamide; CH2Cl2; H2O / 1.5 h / 0 °C 2: toluene / Heating View Scheme

in toluene Heating;