1: HCl / ethyl acetate / 0.5 h / Ambient temperature 2: 1.) EDC; 2.) Et3N / 1.) DMF, 25 deg C, 24 h; 2.) acetonitrile, water, r.t. View Scheme

With  1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride in  various solvent(s)  

With  N'-(3-dimethylaminopropyl)-N-ethylcarbodiimide in  N,N-dimethyl acetamide 3 h;   

Multi-step reaction with 7 steps 1: 3.4 M REDAL / tetrahydrofuran; toluene / 0.5 h / 85 °C2: triethylamine / tetrahydrofuran / 90 h3: pyridine / 6 h / Ambient temperature4: lithium chloride / dimethylformamide / 0.42 h / 80 °C5: ammonium formate / 10percent Pd/C / tetrahydrofuran; methanol / 0.33 h / Ambient temperature6: hydrogen chloride gas / ethyl acetate / 0.67 h7: 58 percent / EDC / N,N-dimethyl-acetamide / 3 h  

Multi-step reaction with 5 steps 1: pyridine / 6 h / Ambient temperature2: lithium chloride / dimethylformamide / 0.42 h / 80 °C3: ammonium formate / 10percent Pd/C / tetrahydrofuran; methanol / 0.33 h / Ambient temperature4: hydrogen chloride gas / ethyl acetate / 0.67 h5: 58 percent / EDC / N,N-dimethyl-acetamide / 3 h  

Multi-step reaction with 3 steps 1: ammonium formate / 10percent Pd/C / tetrahydrofuran; methanol / 0.33 h / Ambient temperature2: hydrogen chloride gas / ethyl acetate / 0.67 h3: 58 percent / EDC / N,N-dimethyl-acetamide / 3 h  

Multi-step reaction with 2 steps 1: HCl2: 1.) HCl; 2.) EDC / 1.) EtOAc, 25 deg C, 15-30 min; 2.) DMF, 25 deg C, 24 h