| 摘要 |
PURPOSE:To obtain the peptide useful as a therapeutic agent for hypertension or pulmonary hypertension, showing antagonism on an endothelin receptor, especially on an endothelin B receptor, by subjecting a specific straight-chain pentapeptide to ring closure condensation. CONSTITUTION:This peptide of formula I {A is D-neutral-alpha-amino acid residue; X is alpha-amino acid residue; Y is amino acid residue [with the proviso that an alpha-amino acid sequence of formula II (R<10> is H or 1-8C alkyl; R<11> is 1-8C alkyl)]; B is neutral-alpha-amino acid residue; C is L-alpha-amino acid residue; D is aromatic group-containing D-alpha-amino acid residue} is obtained by condensing a raw material containing a reactive carboxyl group corresponding to one of two fragments prepared by dividing the peptide of formula I at an arbitrary position with a raw material containing a reactive amino group corresponding to the other fragment to form a straight-chain pentapeptide and further subjecting the resulting substance to ring-closure condensation. |
