This invention offers isoxazole derivatives represented by thefollowing formula (I)(see formula I)in which R1 and R2 each stands for hydrogen, lower alkyl,amino and the like； R3 stands for substituted or unsubstitutedaryl or hetero aryl； R4 stands for hydrogen or lower alkyl； R5stands for substituted or unsubstituted phenyl, furyl and thelike； and Y stands for -CH2-, -CO-, -O-, -NH- and the like,or pharmaceutically acceptable salts thereof which exhibit excellentp38MAPkinase-inhibiting action with reduced side-effects, anduseful for treating such diseases as chronic rheumatoid arthritis,ulcerative colitis and the like.
