Abstract: The invention relates to new peptidyl-arginine aldehyde compounds of formula (I) Q-D-Xaa-Pro-Arg-H  (I) wherein Q represents an acyl group of formula Q′—OCO, wherein Q′ represents an alkyl-group with 1-3 carbon atoms, D-Xaa represents a 3-cyclobutyl-D-alanyl- or 3-cyclopentyl-D-alanyl group, Pro represents an L-prolyl group, and Arg represents an L-arginyl group, and acid-addition salts thereof, and pharmaceutical compositions comprising them, which are suitable for the prevention and cure of thrombosis and accelerated blood clotting.

Abstract: This invention relates to peptide aldehyde derivatives of formula (I): D-Xaa-Pro-Arg-H, wherein Xaa represent a 2-cycloheptyl-2-hydroxyacetyl or 2-cyclopentyl-2-hydroxyacetyl group, Pro represents an L-prolyl residue and Arg represents an L-arginyl residue, their acid-additon salts formed with an organic or inorganic acid and pharmaceutical compositions containing the same. The compounds of formula (I) of the invention have therapeutic, particularly anticoagulant, antiplatelet and antithrombotic properties.

Abstract: The invention relates to t-butyloxy-carbonyl-D-phenylalanyl-L-prolyl-L-arginine aldehyde hemisulfate and D-phenylalanyl-L-prolyl-L-arginine aldehyde sulfate, which is highly stable in aqueous solution, and to a process for preparing D-phenylalanyl-L-prolyl-L-arginine aldehyde sulfate from D-phenylalanyl-L-prolyl-L-arginine aldehyde hemisulfate or N.sup.G -carboxy derivative containing an acid-sensitive protecting group at its amino terminal, wherein the acid sensitive amino terminal protecting group or optionally the N.sup.G -carboxy group is removed with 1 to 12 N sulfuric acid, applied in 1 to 12 equivalent amounts and the resulting free tripeptide aldehyde sulfate isolated. The D-phenylalanyl-L-prolyl-L-arginine aldehyde sulfate of the invention possesses valuable anti-coagulant activity.

Abstract: The invention relates to D-phenylalanyl-L-prolyl-L-arginine aldehyde sulfate, highly stable in aqueous solution, and to a process for preparing it from D-phenylalanyl-L-prolyl-L-arginine aldehyde hemisulfate or N.sup.G -carboxy derivative containing an acid-sensitive protecting group at its amino terminal, wherein the acid sensitive amino terminal protecting group or optionally the N.sup.G -carboxy group is removed with 1 to 12 N sulfuric acid, applied in 1 to 12 equivalent amounts and the resulting free tripeptide aldehyde sulfate is isolated. The D-phenylalanyl-L-prolyl-L-arginine aldehyde sulfate of the invention possesses valuable anticoagulant activity.

Abstract: Anti-coagulants of the formula X-Pro-Agm(HB) (.sub.n) whereinX is an alpha-amino acid moiety of the configuration having a phenyl, phenyl-(lower)-alkyl or phenyl-(heteroatom-containing) lower alkyl side chain,Agm is an agmatine group (1-amino-4-guanidino-butane),B is an acid residue, andn is an integer from 0-2, are disclosed.

Abstract: Novel peptidyl-arginine aldehyde derivatives and their salts of formula I, ##STR1## 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.