1: 1.) 1-hydroxybenzotriazole hydrate (HOBT), N-methylmorpholine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) / 1 a.) DMF, from -20 deg C to 0 deg C, 1 h, b.) 0 deg C, 24 h, 2 a.) DMF, 0 deg C, 4 h, b.) from 0 deg C to RT, 20 h 2: TFA / 1.) CH2Cl2, from -10 deg C to 0 deg C, 4 h,2.) THF, water, RT, 18 h 3: 68 percent / HOBT, N-methylmorpholine, EDC / dimethylformamide / 24 h / Ambient temperature View Scheme