1: With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride in tetrahydrofuran; dichloromethane T=20°C; 1 h; 2: With ammonia in tetrahydrofuran; dichloromethane T=20°C; 4.25 h; 3: With ammonium hydroxide in tetrahydrofuran; dichloromethane; water T=20°C; 20 h;

1.1: tetrahydrofuran / 1.5 h / -40 °C 1.2: 1 h / 20 °C 2.1: tert.-butyl lithium / hexane; tetrahydrofuran / 2 h / -78 - 5 °C 2.2: 1.25 h / -78 - 20 °C 3.1: 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; benzotriazol-1-ol / dichloromethane; tetrahydrofuran / 1 h / 20 °C 3.2: 4.25 h / 20 °C 3.3: 20 h / 20 °C View Scheme

1.1: tert.-butyl lithium / hexane; tetrahydrofuran / 2 h / -78 - 5 °C 1.2: 1.25 h / -78 - 20 °C 2.1: 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; benzotriazol-1-ol / dichloromethane; tetrahydrofuran / 1 h / 20 °C 2.2: 4.25 h / 20 °C 2.3: 20 h / 20 °C View Scheme