Disclosed are compounds of formula (I) Where Ar.sub.1, X, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are defined herein. The compounds of the invention inhibit production of cytokines involved in inflammatory processes and are thus useful for treating diseases and pathological conditions involving inflammation such as chronic inflammatory disease. Also disclosed are processes for preparing these compounds and pharmaceutical compositions comprising these compounds.