Discovery of Novel Cyanodihydropyridines as Potent Mineralocorticoid Receptor Antagonists

A new 1,4-dihydropyridine 5a, containing a cyano group at the C3 position, was recently reported to possess excellent mineralocorticoid receptor (MR) antagonist in vitro potency and no calcium channel-blocker (CCB) activity. In the present study, we report the structure activity relationships of this novel series of cyano ester dihydropyridines that resulted in R-6 substituted analogues with improved metabolic stability while maintaining excellent MR antagonist activity and selectivity against other nuclear receptors. Further structure optimization with the introduction of five-membered ring heterocycles at R-6 resulted in compounds with excellent MR antagonist potency and a suitable pharmacokinetic profile. In vivo studies of a promising tool compound in the Dahl salt-sensitive rat model of hypertension showed similar blood pressure (BP) reduction as the steroidal MR antagonist eplerenone, providing proof-of-concept (POC) for a nonsteroidal, orally efficacious MR antagonist.