The invention provides novel compounds having the general formula (I) wherein R1, R2, R3, R4, R5, R6, R7, A1, A2 and A3 are as described herein, compositions including the compounds and methods of using the compounds. These compounds are useful for therapy or prophylaxis in a mammal, and in particular as aldosterone synthase (CYP11B2 or CYP11B1) inhibitors for the treatment or prophylaxis of chronic kidney disease, congestive heart failure, hypertension, primary aldosteronism and Cushing syndrome.