596229 Provided are compounds of formula I, where R5, R6, Z1 and Z2 are as described in the specification. Examples of preferred compounds include 6-({ 4-[2-hydroxy-2-(4-methyl-1-oxo-1,3-dihydro-2-benzofuran-5-yl)ethyl)piperazin-1-yl} methyl)-8,9-dihydro-1H-furo[3,4-f]isochromen-3(6H)-one, 5,5'-{ piperazine-1,4-diylbis[(1R)-1-hydroxyethane-2,1-diyl]bis(4-methyl-2-benzofuran-1-(3H)-one) and 6-[(1S)-1-hydroxy-2-{ 4-[(2R)-2-hydroxy-2-(4-methyl-1-oxo-1,3-dihydro-2-benzofuran-5-yl)ethyl]piperazin-1-yl} ethyl]pyridine-3-carbonitrile. The compounds inhibit renal outer medullary potassium (ROMK) channel (Kir1.1). The compounds are useful as diuretics, natriuretics and in the therapy of cardiovascular diseases such as hypertension, and disorders resulting from excessive salt and water retention.
