4-(N,N-dimethlyamino)pyridine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride in tetrahydrofuran 18 h; Ambient temperature;

1: 1.) t-BuOK, 18-crown-6 / 1.) THF, 15 min, 2.) THF, RT, 3.5 h 2: 36 percent / 2 N aq. KOH / ethanol; tetrahydrofuran / Ambient temperature 3: 51 percent / N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, 4-dimethylaminopyridine / tetrahydrofuran / 18 h / Ambient temperature View Scheme

1: 1.) t-BuOK, 18-crown-6 / 1.) THF, 15 min, 2.) THF, RT, 3.5 h 2: 36 percent / 2 N aq. KOH / ethanol; tetrahydrofuran / Ambient temperature 3: 51 percent / N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, 4-dimethylaminopyridine / tetrahydrofuran / 18 h / Ambient temperature View Scheme

1: 36 percent / 2 N aq. KOH / ethanol; tetrahydrofuran / Ambient temperature 2: 51 percent / N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, 4-dimethylaminopyridine / tetrahydrofuran / 18 h / Ambient temperature View Scheme