The present invention provides compounds of formula (I): ##STR00001## and pharmaceutically acceptable salts thereof, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5r.sup.6, m and n are defined as described herein. The invention also provides methods of making the compounds of formula (I), and methods of treating inflammatory diseases, such as rheumatoid arthritis, in a mammal comprising administering a therapeutically effective amount of a compound of formula (I) to the mammal.