1: TFA / CH2Cl2 / 1 h / Ambient temperature; stoppered flask 2: 1-ethyl-3-<3-(dimethylamino)propyl>carbodiimide hydrochloride / dimethylformamide / 40 °C 3: TFA / CH2Cl2 4: EDC / dimethylformamide / 40 °C 5: H2 / 5percent Pd/C / dimethylformamide / 2 h / 3102.9 Torr / Ambient temperature 6: 88 percent / DCC / dimethylformamide / 1.) 70 min, 0 deg C, 2.) 40 deg C, overnight 7: 1.) NaHCO3, 2.) HCl / H2O; dioxane / 1.) 15 min, ice-cooled, 2.) room temperature, overnight View Scheme

1: TFA / CH2Cl2 / 1 h 2: 1.) dicyclohexylcarbodiimide, HOBt, 2.) TEA / 1) CH2Cl2, 1 h; 2) CH2Cl2, 2 h, 0 deg C, 20 deg C (15 h) 3: 95 percent / H2 / Pd/C / ethanol / 12 h View Scheme

1: TFA / CH2Cl2 / 1 h 2: 1.) dicyclohexylcarbodiimide, HOBt, 2.) TEA / 1) CH2Cl2, 1 h; 2) CH2Cl2, 2 h, 0 deg C, 20 deg C (15 h) 3: 95 percent / H2 / Pd/C / ethanol / 12 h 4: 59 percent / TFA, EDC / dimethylformamide / Ambient temperature 5: 77 percent / H2 / Pd/C / dimethylformamide / 6 h / Ambient temperature View Scheme