Compounds selected from the group of compounds represented by formula I: ##STR1## where: R.sub.10 is represented by the formula (A), (B), or (C): ##STR2## R.sub.20 is represented by the formula (U), (V), or (W): ##STR3## and the other substituents are as defined in the specification; and their pharmaceutically acceptable salts; are inhibitors of prostaglandin G/H synthase and are anti-inflammatory and analgesic agents.