1: diphenyl phosphoryl azide / 1,3-dimethyl-imidazolidin-2-one; toluene / 2 h / 140 °C 2: 140 °C 3: trifluoroacetic acid / dichloromethane / 0.5 h / 20 °C 4: methylamine / ehanol / 2 h / 90 °C View Scheme