Inhibitors of the renal outer medullary potassium channel

A compound of the formula

• or a pharmaceutically acceptable salt thereof,
• wherein:
• Z is
• where is a single or double bond;
• R is independently H, alkyl or haloalkyl;
• R1 is H, alkyl, —F, —OR, or —N(R13)(R14);
• R2 is H or alkyl optionally substituted by 1-5 halogen atoms or —OR;
• R3 is H or alkyl;
• R4 is H or alkyl optionally substituted by 1-5 halogen atoms or —OR;
• R5 is H or alkyl optionally substituted by 1-5 halogen atoms or —OR;
• or R4 and R5 are joined together to represent —CH2CH2-, —CH2NCH2-, —CH2N(CH3)CH2- or —CH2OCH2-;
• R6 is H, halo, alkyl optionally substituted by 1-5 halogen atoms or —OR, cycloalkyl or —OR;
• or R6 and R1 are joined together to represent —CH2CH2O—;
• R7 is H, halo, alkyl optionally substituted by 1-5 halogen atoms or —OR, cycloalkyl or —OR;
• R8 is independently H or alkyl;
• R8′ is H or alkyl;
• R9 is —CN, tetrazolyl, or —S(O)2R13;
• R10 is halo, —OR, alkyl optionally substituted by 1-5 halogen atoms or —OR, —S-alkyl, —N-alkyl or —O-cyclopropyl;
• R11 is —CN, —S(O)2R13, or optionally substituted heteroaryl wherein the optional substituent is halogen or alkyl;
• R12 is H, halo, alkyl, cycloalkyl, or —OR;
• R13 is H, alkyl, allyl or cycloalkyl;
• R14 is H, alkyl or cycloalkyl;
• R15 independently oxo, —F, —CN, alkyl optionally substituted by 1-5 fluroine atoms or —OR, cycloalkyl, heteroaryl optionally substituted by halogen, —CN, alkyl or haloalkyl;
• a is 1 or 2;
• and
• n is 0, 1 or 2.