Endothelin antagonistic peptide

A peptide derivative of the formula:

• ##STR26## wherein R.sup.2 is a hydrogen atom or a lower alkyl group;
• R.sup.3 is a lower alkyl group which is unsubstituted or substituted with a lower alkylthio group, a lower alkenyl group, a cycloalkyl group or a cycloalkyl lower alkyl group wherein optional one to four hydrogen atoms on the ring may independently be replaced by a lower alkyl group, an aryl group, a heteroaryl group, an aryl lower alkyl group or a heteroaryl lower alkyl group;
• R.sup.4 is a hydrogen atom, a lower alkyl group or an acyl group;
• X and Y are mutually dependent;
• when X is a group of the formula R.sup.11 --O--C(.dbd.O) or a group of the formula R.sup.12 R.sup.13 N--C(.dbd.O), Y is a group of the formula:
• ##STR27## wherein R.sup.11 is a lower alkyl group or an aryl group, R.sup.12 is a lower alkyl group, a cycloalkyl group, a cycloalkyl lower alkyl group, a 1-adamantyl group, or an aryl group or a heteroaryl group wherein optional one or two hydrogen atoms on the ring may independently be replaced by an optional group selected from the group consisting of a lower alkyl group, a lower alkoxy group, a halogen atom, a trifluoromethyl group, a nitro group, an amino group and a formyl amino group, R.sup.13 is a hydrogen atom, a lower alkyl group which is unsubstituted or substituted with a hydroxyl group, a cycloalkyl group or a cycloalkyl lower alkyl group, or R.sup.12 and R.sup.13 form, together with the adjacent nitrogen atom, a 5- to 9-membered nitrogen-containing saturated heterocyclic ring having 4 to 8 carbon atoms (wherein among methylene groups forming the ring, optional one methylene group may be replaced by a thio group, optional one to four hydrogen atoms on the carbon atoms of the heterocyclic ring may independently be replaced by a lower alkyl group or a hydroxy lower alkyl group, and further two adjacent carbon atoms in the heterocyclic ring may form a benzo fused ring), R.sup.5 is a hydrogen atom, or a lower alkyl group or a lower alkenyl group which may have one to three substituents selected from the group consisting of a hydroxyl group, a lower alkoxy group, a lower alkylthio group, an aryl group and a heteroaryl group, n is 0 or 1, Z is a hydroxymethyl group, a group of the formula CO.sub.2 R.sup.61 (wherein R.sup.61 is a hydrogen atom or a lower alkyl group), a group of the formula CONR.sup.62 R.sup.63 (wherein each of R.sup.62 and R.sup.63 is independently a hydrogen atom, an aryl group, a heteroaryl group, or a lower alkyl group which may have one to three substituents selected from the group consisting of a hydroxyl group, a carboxyl group and a sulfo group), a 1H-tetrazol-5-yl group, a sulfo group or a phosphono group, and when X is a group of the formula:
• ##STR28## , Y is a group of the formula:
• ##STR29## wherein R.sup.71 is a hydrogen atom, R.sup.72 is a lower alkyl group which is unsubstituted or substituted with a lower alkylthio group, a cycloalkyl group, an aryl group or a heteroaryl group, or R.sup.71 and R.sup.72 together form an alkylene group having 2 to 5 carbon atoms, m is 0, 1 or 2, Q is a group of the formula COOR.sup.8 (wherein R.sup.8 is a hydrogen atom or a lower alkyl group), a sulfo group or a 1H-tetrazol-5-yl group, each of R.sup.91 and R.sup.92 is independently a hydrogen atom, or a lower alkyl group or a lower alkenyl group which may have one to three substituents selected from the group consisting of a hydroxyl group, a lower alkoxy group, a mercapto group, a lower alkylthio group, a carboxyl group, a carbamoyl group, an amino group, a guanidino group, an aryl group and a heteroaryl group, or R.sup.91 and R.sup.92 together form an alkylene group having 2 to 4 carbon atoms wherein optional one hydrogen atom in the alkylene group may be replaced by a hydroxyl group, and one sulfur atom may be present, and U and W together form a single bond;
• or a pharmaceutically acceptable salt thereof.