ENDOTHELIN ANTAGONISTIC SUBSTANCE

摘要

Disclosed is a peptide derivative of the formula: (see formula I) (wherein: A is R11O-CO- (wherein R11 is alkyl or phenyl) , or R12R13N-C(=O)- (wherein R12 is alkyl, cycloalkyl, 1-adamantyl, optionally substituted phenyl, pyridyl or thienyl and R13 is H, alkyl or cycloalkyl or R12 and R13 form, together with the adjacent nitrogen atom, a 5- to 9-membered nitrogen-containing saturated heterocyclic ring having 4 to 8 carbon atoms, optionally methylene replaced by thio and optionally having substituent or being benzo-fused); B is O or -NR2- (wherein R2 is H or alkyl); R3 is alkyl, cycloalkyl, aryl, heterocyclic, cycloalkyl-alkyl, aryl-alkyl or heterocyclic-alkyl; X1 is O or -NR4- (wherein R4 is H or alkyl); R5 is a 3-indolylmethyl, 3-benzothienylmethyl, 1- naphthylmethyl or benzyl group, each optionally substituted; X3 is O or S; R6 is H, alkyl or alkenyl; n is 0 or 1; Y is CH2OH, CO2R71 (wherein R71 is H or alkyl) , CONHR72 (wherein R72 is H or alkyl), 1H-tetrazol-5-yl, sulfo or phosphono) or a pharmaceutically acceptable salt thereof, which has endothelin antagonistic activity and is useful as a drug.