Closely related isoxazoles may exhibit opposite immunological activities.

Advances of modern medicine require constant supply of new drugs displaying specific therapeutic actions. Bio-accessibility and lack of side-effects are highly desired features of new therapeutics. Modifications of the isoxazole structure offer a possibility of generating potential drugs exhibiting a wide array of biological activities, as described by us during the last decade (1-10). A majority of compounds from the isoxazole family are immunosuppressive or anti-inflammatory (8, 10-12). However, even a minor modification of the isoxazole structure may lead to unexpected biological activity (5). Among compounds, synthesized recently in the Department of Organic Chemistry, two isoxazoles require special attention and were the subject of more detailed investigations (5, 8, 10). These compounds exhibited strong, directional, immunotropic actions and may be potentially applied for various therapeutic goals.