As an important class of heterocycles, isoxazole is a five membered heterocyclic compound with various pharmacological actions, which is found in some natural products, such as ibotenic acid. It is used in the formation of the basis for a number of drugs, such as the COX-2 inhibitor valdecoxib and anti-inflammatory drugs. Isoxazoles are largely applied in the area of pharmaceuticals and therapeutics, including insecticidal, antibacterial, antibiotic, antitumour, antifungal, antituberculosis, anticancer and ulcerogenic. Besides, it has a great effect on reducing blood glucose, eliminating pain, resisting inflammation, killing harmful bacteria, controlling and reducing the risk of HIV.
The isoxazole ring is an essential pharmacophore in modern drug discovery. Some beta-lactamase-resistant antibiotics contain an isoxazole group, including cloxacillin, dicloxacillin, flucloxacillin, and the isoxazole group is also found in some steroid drug such as danazol.