Used as a key intermediate in the synthesis of valdecoxib, a selective COX-2 inhibitor for treating osteoarthritis and rheumatoid arthritis. The reactive sulfonyl chloride group facilitates the formation of sulfonamides by reaction with amines, yielding potent anti-inflammatory agents with high specificity for the COX-2 enzyme. Widely employed in medicinal chemistry to develop non-steroidal anti-inflammatory drugs (NSAIDs) that reduce gastrointestinal side effects. The isoxazole moiety provides structural stability and enhances the selectivity and pharmacokinetic profile of the resulting pharmaceuticals.