Discovery of Novel 2-Carbamoyl Morpholine Derivatives as Highly Potent and Orally Active Direct Renin Inhibitors

The renin-angiotensin-aldosterone system (RAAS) plays a key role in the regulation of blood pressure. Renin, the first and rate-limiting enzyme of the RAAS, is an attractive target for the treatment of hypertension and cardiovascular/renal diseases. Therefore, various direct renin inhibitors (DRIs) have been researched over recent decades; however, most exhibited poor pharmacokinetics and oral bioavailability due to the peptidomimetic or nonpeptidomimetic structures with a molecular weight (MW) of >600, and only aliskiren is approved. This study introduces a novel class of DRIs comprised of a 2-carbamoyl morpholine scaffold. These compounds have a nonpeptidomimetic structure and a MW of <500. The representative compound 26 was highly potent despite not occupying S1'-S2' sites or the opened flap region used by other DRIs and exerted a significant antihypertensive efficacy via oral administration on double transgenic mice carrying both the human angiotensinogen and the human renin genes.