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:及其藥學上可接受之鹽,其係為腎外髓質鉀(ROMK)通道(Kir1.1)之抑制劑。式I化合物可作為利尿劑與利鈉尿劑使用,因此可用於治療與預防由於過量鹽與水保留所造成之病症,包括心血管疾病,譬如高血壓及慢性與急性心臟衰竭。