Exorbitant aldosterone is closely associated with various severe diseases,including congestive heart failure and chronic kidney disease.As aldosterone synthase is the pivotal enzyme in aldosterone biosynthesis,its inhibition constitutes a promising treatment for these diseases.Via a structure-based approach,a series of pyridyl substituted 3,4-dihydrobenzo [f] [1,4]oxazepin-5(2 H)-ones were designed as inhibitors of aldosterone synthase.Six compounds(5 j,5 l,5 m 5 w,5 x and 5 y) distinguished themselves with potent inhibition(IC50<100 nmol/L) and high selectivity over homogenous 11β-hydroxylase.As the most promising compound,5 x exhibited an IC50of 12 nmol/L and an excellent selectivity factor(SF) of157,which are both superior to those of the re ference fadrazole(IC50=21 nmol/L,SF=7).Importantly,5 x showed no inhibition against steroidogenic CYP17,CYP19 and a panel of hepatic CYP enzymes indicating an outstanding sa fety profile.As it manifested satis factory pharmacokinetic pro perties in rats,compound5 x was considered as a drug candidate for further development.