1: 86.7 percent / HOBT, 1-ethyl-3-<3-(N,N-dimethylamino)propyl>carbodiimide (WSCD) / dimethylformamide / 3 h / 0 - 20 °C 2: HCl / dioxane; CH2Cl2 / 1.17 h / 0 - 20 °C 3: 94.7 percent / HOBT, 1-ethyl-3-<3-(N,N-dimethylamino)propyl>carbodiimide (WSCD) / dimethylformamide / 3.5 h / 0 - 20 °C 4: 100 percent / HCl / CH2Cl2; dioxane / 1.17 h / 0 - 20 °C 5: 82.4 percent / Et3N / CH2Cl2 / 0.33 h / -15 °C View Scheme