1: With methanol; potassium carbonate T=20°C; 0.5 h; 2: With Dess-Martin periodane in dichloromethane T=20°C;

1: benzotriazol-1-ol; diisopropyl-carbodiimide; copper dichloride / N,N-dimethyl-formamide / 5 h / 0 - 20 °C 2: sodium hydroxide; water / tetrahydrofuran / 18 h / 20 °C 3: benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; triethylamine / dichloromethane / 6 h / 20 °C / |Cooling with ice 4: sodium hydrogencarbonate; potassium bromide; 2,2,6,6-tetramethyl-1-piperidinyloxy, free radical; sodium hypochlorite / dichloromethane / 20 h / 20 °C / |Cooling with ice View Scheme

1: benzotriazol-1-ol; diisopropyl-carbodiimide; copper dichloride / N,N-dimethyl-formamide / 5 h / 0 - 20 °C 2: sodium hydroxide; water / tetrahydrofuran / 18 h / 20 °C 3: benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; triethylamine / dichloromethane / 6 h / 20 °C / |Cooling with ice 4: sodium hydrogencarbonate; potassium bromide; 2,2,6,6-tetramethyl-1-piperidinyloxy, free radical; sodium hypochlorite / dichloromethane / 20 h / 20 °C / |Cooling with ice View Scheme

1.1: (benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate; triethylamine / dichloromethane / 48 h / 20 °C / Inert atmosphere 2.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 2.2: pH 3.5 3.1: 1-hydroxy-7-aza-benzotriazole; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / N,N-dimethyl-formamide / 72 h 4.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 4.2: pH 3.5 5.1: dichloromethane / 72 h / 20 °C 6.1: potassium carbonate; methanol / 0.5 h / 20 °C 6.2: 20 °C View Scheme

1.1: 20 - 80 °C 1.2: 1 h 1.3: DOWEX50wx8 / pH 7 2.1: Dess-Martin periodane / dichloromethane / 1 h / 20 °C 2.2: 48 h 3.1: bis(trichloromethyl) carbonate; 4-methyl-morpholine / dichloromethane / 3.08 h / -78 - -30 °C 4.1: dichloromethane / 72 h / 20 °C 5.1: potassium carbonate; methanol / 0.5 h / 20 °C 5.2: 20 °C View Scheme

1.1: (benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate; triethylamine / dichloromethane / 48 h / 20 °C / Inert atmosphere 2.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 2.2: pH 3.5 3.1: 1-hydroxy-7-aza-benzotriazole; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / N,N-dimethyl-formamide / 72 h 4.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 4.2: pH 3.5 5.1: dichloromethane / 72 h / 20 °C 6.1: potassium carbonate; methanol / 0.5 h / 20 °C 6.2: 20 °C View Scheme

1.1: 1-hydroxy-7-aza-benzotriazole; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / N,N-dimethyl-formamide / 72 h 2.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 2.2: pH 3.5 3.1: dichloromethane / 72 h / 20 °C 4.1: potassium carbonate; methanol / 0.5 h / 20 °C 4.2: 20 °C View Scheme

1.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 1.2: pH 3.5 2.1: 1-hydroxy-7-aza-benzotriazole; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / N,N-dimethyl-formamide / 72 h 3.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 3.2: pH 3.5 4.1: dichloromethane / 72 h / 20 °C 5.1: potassium carbonate; methanol / 0.5 h / 20 °C 5.2: 20 °C View Scheme

1.1: sodium hydroxide / tetrahydrofuran; methanol / 0 - 20 °C 1.2: pH 3.5 2.1: dichloromethane / 72 h / 20 °C 3.1: potassium carbonate; methanol / 0.5 h / 20 °C 3.2: 20 °C View Scheme

1.1: Dess-Martin periodane / dichloromethane / 1 h / 20 °C 1.2: 48 h 2.1: bis(trichloromethyl) carbonate; 4-methyl-morpholine / dichloromethane / 3.08 h / -78 - -30 °C 3.1: dichloromethane / 72 h / 20 °C 4.1: potassium carbonate; methanol / 0.5 h / 20 °C 4.2: 20 °C View Scheme