(X) __. _ u. The amide X was synthesized analogously to compound V from 0.3 g (0.0006 mole) of the pentafluorophenyl ester of di-tert-butyloxycarbonyl-L-ornithine, 0.08 ml (0.0006 mole) triethylamine, and 0.32 g (0~ mole) of the tripeptide trifluoroacetate VIII. After evaporation of the reaction mixture, the residue was dissolved in an ethyl acetate-water mixture, i: io The organic layer was removed and washed with a 5% solution of KHSO~, ...