D-Fenylalanyl-L-prolyl-L-arginine-aldehydederivaat, werkwijze voor de bereiding hiervan

Novel peptidyl-arginine aldehyde derivatives and their salts of formula I, wherein X represents a hydrogen atom, benzoyl or tert-butyloxycarbonyl group, and Y is a D-phenylalanine, beta -phenyl-D-lactic acid or D-allo-isoleucine moiety, are prepared from peptidyl-arginine aldehydes protected by an urethane type protecting group on their N- or O-terminal and/or a guanidino group, by removing the protecting group in a mixture of lower alkanols and water by means of hydrogenolysis, and eventually converting the product formed into a salt. The compounds of formula I possess valuable antithrombin activity.