compounds of the formula wherein : x is selected from the group consisting of trihalomethyl , c 1 - c 6 alkyl , and a group of formula ii : wherein : r 3 and r 4 are independently selected from the group consisting of hydrogen ; halogen ; hydroxyl ; nitro ; c 1 - c 6 alkyl ; c 1 - c 6 alkoxy ; carboxy ; c 1 - c 6 trihaloalkyl ; and cyano ; z is selected from the group consisting of substituted and unsubstituted aryl ; or a pharmaceutically acceptable salt thereof . the compounds are inhibitors of cyclooxygenase - 2 activity . they are useful for treating cyclooxygenase - mediated disorders , including , for example , inflamation , neoplastic disorders and angiogenesis - mediated disorders .