5-substituted 4-isoxazoleacetic acids with analgesic activity

The synthesis of some 5-substituted 4-isoxazoleacetic acids starting from 5-substituted 4-isoxazolemethanols via their conversion to 4-(bromomethyl)isoxazoles, 4-isoxazoleacetonitriles and acid hydrolysis of the latter is described. 5-Ethyl- and 5-propyl-4-isoxazoleacetic acids showed in the writhing test an analgesic activity comparable to that of aspirin.