119.44 mg of ethyl 3-amino-3-(3,5-dichlorophenyl)propionate, 0.164 g of 3-benzyloxy-2-[3-(pyridin-2-ylamino)propoxycarbonylamino]propionic acid, 10.00 ml of DMF, 0.084 g of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride and 0.097 ml of 4-methylmorpholine are reacted together with stirring firstly for 1.5 hours at 50° C. and subsequently overnight at room temperature. After removal of the DMF by distillation, the residue is taken up in ethyl acetate, washed with water, evaporated to dryness and purified by chromatography over a short silica column (eluent ethyl acetate), giving ethyl 3-{3-benzyloxy-2-[3-(pyridin-2-ylamino)propoxycarbonylamino]propanoylamino}-3-(3,5-dichlorophenyl)propionate, RT 1.552 min, FAB-MS (M+H)+ 618.
