rofecoxib [Chemical/Ingredient] 232158 C116926 C23406 rofecoxib 4-(4-methylsulfonylphenyl)-3-phenyl-5H-furan-2-one C0762662 rofecoxib N0000006529 M0300376 rofecoxib Lactones [Chemical/Ingredient] Sulfones [Chemical/Ingredient]