Glycyrrhetinic acid derivatives for treating hyperkalemia

A compound of formula I or a salt thereof:

• wherein,
• X is a bond, —O—, —C(O)—, —N(Rx)—, —C(O)N(Rx)—, —N(Rx)—C(O)—, —S(O)n—N(Rx)— or —N(Rx)—S(O)n—;
• V is —C(O)O—, —C(O)N(R5)—, —C(O)N(R5)O—, —NH—C(O)—N(R5)— or NH—S(O)n—;
• L is a bond, alkylene wherein one or more non-adjacent methylene groups of said alkylene are replaced with —O—;
• divalent aryl or divalent heteroaryl;
• or L is alkylene-Y-alkylene wherein Y is O, NRx, S, SO, SO2 or a divalent heterocycle;
• wherein said alkylene groups are optionally substituted with OH, —C(O)O—R1, alkyl or alkyl substituted with OH or —C(O)O—R1;
• and wherein a carbon of said alkylene groups and Rx optionally together form a heterocycle;
• provided that when X is other than a bond, then L is other than a bond;
• R1 is alkyl optionally substituted with halogen, OH, amino, oxo, carboxy, acyloxy, alkoxycarbonyl, alkoxyacyloxy, alkoxycarbonyloxy, aminocarbonyl, a carbocycle optionally substituted with alkyl, haloalkyl, oxo, amino and halogen and a heterocycle optionally substituted with alkyl, oxo, amino and halogen;
• and a carbocycle or heterocycle optionally substituted with alkyl, haloalkyl, oxo, amino and halogen;
• wherein one or more non-adjacent methylene groups in any of the foregoing alkyl groups is replaced with O;
• R2 is H or R1;
• R3 is absent, Me;
• provided that when —X-L-C(O)O—R1 depends from the carbon to which R3 depends then R3 is absent;
• or R3 is —Z-L-C(O)O—R1 wherein Z is a bond, —O—, —N(Rx)—, —C(O)N(Rx)—, —N(Rx)—C(O)—, —S(O)n—N(Rx)— or —N(Rx)—S(O)n—;
• and
• R4 is absent, H or OH;
• provided that when —X-L-C(O)O—R1 depends from the carbon to which R4 depends then R4 is H or absent;
• R5 is H or alkyl;
• Rx is H, —C(O)O—R1, or alkyl optionally substituted with —C(O)O—R1;
• and
• n is 1 or 2.