PEPTIDE COMPOUND AND ITS PRODUCTION

PURPOSE:To obtain the subject new compound, having endothelin antagonistic action and useful for treating hypertension, angina pectoris, cardiac infarction, etc., by a method for successively reacting amino acids, etc., having protected functional groups other than those required for reaction and then removing the protecting groups. CONSTITUTION:A compound expressed by formula I [R is H or acyl ; R is lower alkyl, (substituted) ar(lower)alkyl, (substituted) heterocyclic (lower)alkyl, etc.; A is O, NH, lower alkylimino or lower alkylene] or its reactive derivative at the carboxyl group or salt thereof is reacted with a compound expressed by formula II [R is (substituted) heterocyclic (lower)alkyl or ar(lower)alkyl; R is H or (substituted) lower alkyl; R is (protected) carboxy, etc.; R is H or (substituted) lower alkyl; R is H or lower alkyl] or its reactive derivative at the amino group or salt thereof to afford the objective peptide compound (salt) expressed by formula III.