Abstract: Compounds of formula I provide pharmacological agents which are inhibitors of the P450 enzyme, aldosterone synthase, and thus may be employed for the treatment of aldosterone mediated conditions. Accordingly, the compounds of formula I may be employed for prevention, delay of progression, or treatment of hypokalemia, hypertension, congestive heart failure, renal failure, in particular, chronic renal failure, restenosis, atherosclerosis, syndrome X, obesity, nephropathy, post myocardial infarction, coronary heart diseases, increased formation of collagen, fibrosis, and remodeling following hypertension and endothelial dysfunction. Preferred are the compounds of formula I which are selective inhibitors of aldosterone synthase devoid of undesirable side effects due to general inhibition of cytochrome P450 enzymes.