Compounds of formula I wherein: one of X or Y represents N and the other represents C； R1 represents hydrogen, methyl, halogen, cyano, nitro, -CHO, -COCH3 or -COOR4； R2 represents optionally-substituted aryl or heteroaryl； R3 represents C1-8 alkyl, C1-8 haloalkyl or -NR4R6； R4 represents hydrogen, C1-8 alkyl or arylC0-8 alkyl； R6 represents hydrogen, C1-8 alkyl, arylC1-8 alkyl, -COR8 or -COOR8； R8 represents C1-8 alkyl or C1-8 haloalkyl； aryl in the above definitions represents phenyl or naphthyl； and heteroaryl in the above definitions represents pyridine, pyrazine, pyrimidine or pyridazine, which can be optionally fused to a benzene ring. These compounds are useful as cyclooxygenase-2 inhibitors. <；CHEM>；
