trifluoroacetic acid in dichloromethane T=20°C; 0.5 h;

1: 4-(N,N-dimethlyamino)pyridine / dichloromethane / 3 h / 20 °C 2: n-butyllithium / tetrahydrofuran / 1 h / -78 °C 3: trifluoroacetic acid / dichloromethane / 0.5 h / 20 °C View Scheme

1: n-butyllithium / tetrahydrofuran / 1 h / -78 °C 2: trifluoroacetic acid / dichloromethane / 0.5 h / 20 °C View Scheme

1: trifluoroacetic acid / acetic acid / 24 h / 140 °C 2: diphenyl phosphoryl azide / 1,3-dimethyl-imidazolidin-2-one; toluene / 2 h / 140 °C 3: 140 °C 4: trifluoroacetic acid / dichloromethane / 0.5 h / 20 °C 5: methylamine / ehanol / 2 h / 90 °C View Scheme

trifluoroacetic acid in dichloromethane T=20°C; 0.5 h;

1: 4-(N,N-dimethlyamino)pyridine / dichloromethane / 3 h / 20 °C 2: n-butyllithium / tetrahydrofuran / 1 h / -78 °C 3: trifluoroacetic acid / dichloromethane / 0.5 h / 20 °C View Scheme

1: n-butyllithium / tetrahydrofuran / 1 h / -78 °C 2: trifluoroacetic acid / dichloromethane / 0.5 h / 20 °C View Scheme