Takeda Chemical Industries, Inc.

Akira Kawada

Mitsuhiro Wakimasu

Takashi Kikuchi

Hideo Shirafuji

Masaaki Mori

A cyclic hexapeptide represented by the formula:

Cyclic hexapeptides, their production and use

Disclosed are (1) a cyclic hexapeptide represented by formula I or a salt thereof: ##STR1## wherein X and Y each represent .alpha.-amino acid residues, A represents a D-acidic-.alpha.-amino acid residue, B represents a neutral-.alpha.-amino acid residue, C represents an L-.alpha.-amino acid residue and D represents a D-.alpha.-amino acid residue having an aromatic ring group; and (2) a pharmaceutical composition comprising the peptide represented by formula I or a pharmaceutically aceptable salt thereof as an active ingredient.

Cyclic endothelin antagonists

Cyclic peptides and their salts have antagonistic activity on endothelin receptors and antagonistic activity on NK2 receptors. The peptides have the formula ##STR1## wherein X and Y each represent .alpha.-amino acid residues, A represents a D-acidic-.alpha.-amino acid residue, B represents a neutral .alpha.-amino acid residue, C represents an L-.alpha.-amino acid residue and D represents a D-.alpha.-amino acid residue having an aromatic ring group; wherein hydroxy, thiol, amino, imino and carboxyl groups can be substituted or unsubstituted. Pharmaceutical compositions containing such peptides are also described.

Cyclic peptides and use thereof

A phosphonic acid derivative compound represented by formula [I ] or a pharmaceutically acceptable salt thereof: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 each represent hydrocarbon groups which may be substituted, except cases in which (1) R.sub.2 is unsubstituted methyl, ( 2 ) R.sub.3 is an unsubstituted hydrocarbon group having 1 to 3 carbon atoms, and (3) R.sub.1 is benzyloxycarbonylaminomethyl, R.sub.2 is isobutyl and R.sub.3 is isobutyl or phenylmethyl, which has endothelin-converting enzyme inhibiting activity and is useful as pharmaceutical drugs such as therapeutic agents for hypertension, cardiac or cerebral circulatory diseases and renal diseases.

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Ibaraki, Japan

Akira Kawada