Indole derivatives useful as endothelin receptor antagonists

A compound of formula I

• wherein
• R1 and R2 are optional substituents and independently represent C1-6 alkyl, C2-6 alkenyl C2-6 alkynyl, halogen C1-3 perfluoroalkyl, (CH2)mAr1. (CH2)mHer1, (CH2)mCONR7R8, (CH2)mCO2R8, O(CH2)qCO2R8, (CH2)mCOR8. (CH2)mOR8. O(CH2)pOR8. (CH2)mNR7R8, CO2(CH2)qNR7R8, (CH2)mCN, S(O)nR8, SO2NR7R8, CONH(CH2)mAr1 or CONH(CH2)mHer1;
• R3 represents H, C1-6 alkyl, (CH2)pNR9R10, SO2R10, SO2NR9R10, (CH2)mCOR10, C2-6 alkenyl, C2-6 alkynyl, (CH2)mCONR9R10, (CH2)mCO2R10, (CH2)pCN, (CH2)pR10 or (CH2)pOR10;
• R4 and R9 independently represent H or C1-6 alkyl;
• R7 represents H, C1-6 alkyl or C1-6 alkoxy;
• R5 represents H or OH;
• R6 represents methylenedioxyphenyl, alkoxy and halogen,
• R8 and R10 independently represent H, C1-6 alkyl, Ar2 , Het2 or C1-6 alkyl substituted by Ar2 or Het2;
• Z represents CO2H, COHN(tetrazol-5-yl), CONHSO2O(C1-4alkyl), CO2Ar3, CO2(C1-6 alkyl), tetrazol-5-yl, CONHSO2Ar3. CONHSO2(CH2)qAr3 or CONHSO2 (C1-6alkyl);
• m represents 0, 1, 2 or 3;
• n represents 0, 1 or 2;
• p represents 2, 3 or 4;
• q represents 1, 2 or 3;
• Ar1-3 independently represent phenyl, naphthyl, or an aromatic heterocycle having 5 ring members 2 to 4 which are selected from N, S and O, which aromatic heterocycle is optionally fused to a benzene ring, and which phenyl group is optionally fused to an aromatic heterocycle as defined immediately above, the group as a whole being optionally substituted by one or more groups falling within the definition of R1 above;
• and
• Het1 and Het2 independently represent a non-aromatic heterocycle having 5 ring members 2 to 4 of which are selected from N, S and O, which group is optionally substituted by one or more groups falling within the definition of R1 above, and is further optionally substituted by ═O or ═S;
• or a pharmaceutically acceptable salt thereof.