This invention relates to compounds having structural Formula I: and pharmaceutically acceptable salts thereof which are inhibitors of the Renal Outer Medullary Potassium (ROMK) channel (Kir1.1). The compounds of Formula I are useful as diuretics and natriuretics and therefore are useful for the therapy and prophylaxis of disorders resulting from excessive salt and water retention, including cardiovascular diseases such as hypertension and chronic and acute heart failure.本發明係關於具有結構式I之化合物:及其醫藥學上可接受之鹽,其為腎外髓質鉀(Renal Outer Medullary Potassium,ROMK)通道(Kir1.1)之抑制劑。該等式I化合物適用作利尿劑及鈉利尿劑,且因此適用於治療及預防由過量鹽及水滯留所致之病症,包括心血管疾病,諸如高血壓以及慢性及急性心臟衰竭。