1.1: 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; benzotriazol-1-ol / tetrahydrofuran / 0.5 h 1.2: 20 °C 2.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / methanol; tetrahydrofuran / 12 h / |Reflux 3.1: trifluoroacetic acid; methoxybenzene; sulfuric acid / 0.5 h / 90 °C 4.1: hydrogenchloride; water / acetonitrile / 10 h / |Reflux View Scheme