1.1: triethylamine / dichloromethane / 3 h / 0 - 10 °C 2.1: 4-(N,N-dimethlyamino)pyridine / toluene / 0 - 30 °C 3.1: hydrogenchloride / water; tetrahydrofuran / 24 h / 0 - 30 °C 3.2: 24 h / 25 - 30 °C View Scheme