Isoxazole

OBJECTIVE: Considerable interest have been focused on isoxazole and pyrazole structures, which has been known to possess a broad spectrum of biological
activities such as analgesic, anti-inflammatory, anticancer,etc, (1). All the isoxazole and pyrazole derivatives were prepared from the appropriate b-diketones by
reaction with Hydroxylamine Hydrochloride and Hydrazine hydrate respectively.ABSTRACT : In view of the biological importance it was proposed to prepare
some Diaryl isoxazoles and pyrazoles and study their biological activities. All the isoxazole and pyrazole derivatives were prepared from the appropriate b-
diketones by reaction with Hydroxylamine Hydrochloride and Hydrazine hydrate respectively, (2). The structures of the synthesized compounds were determined
by using different analytical techniques like 1HNMR, IR and Mass spectroscopy. Almost all the non steroidal anti-inflammatory drugs (NSAID’S) under current
clinical usage are highly acidic in nature and suffer from a common drawback of gastrointestinal toxicity, thus indicating a clear need to develop a non-acidic nonsteroidal
anti-inflammatory agent, (3). Among all the compounds tested, compounds 4, 5, 6, 7, 8, 9, showed significant anti inflammatory activity. It was concluded
that pyrazoles showed significant anti inflammatory activity than that of Isoxazoles.PRINCIPLE CONCLUSION: Di chloro substituted benzene ring at
position 3 of the Pyrazoles and Isoxazoles exhibited moderate antibacterial activity and antifungal activity when compared to that of mono chloro substituted
benzene ring at position 3 of Isoxazole and pyrazoles. 3, 4 di chloro substituted benzene ring at position 3 of the pyrazoles and Isoxazoles showed significant
antifungal activity.
Key words: Isoxazole, pyrazole, anti inflammatory, bactericidal and fungicidal

This microreview summarizes data published over the past 10 years devoted to the synthesis of substituted 2,1-benzisoxazoles. The major synthetic approaches aim at increasing either the electrophilicity or nucleophilicity of ortho substituents or other substrates. Ortho-substituted aryl azides, anilines, nitroso- and nitrobenzenes were used as starting compounds.

Aromatic aldehydes upon reaction with aromatic ketones in presence of sodium hydroxide yield Chalcones (1a-l) which upon bromination in presence of glacial acetic acid formed chalcone dibromide (2a-l), which undergoes a subsequent cyclization on reaction with hydroxalamine hydrochloride in presence of TEA affording substituted diphenyl isoxazoles (3a-l) in high yield. These compounds were characterized by UV, FTIR, 1 HNMR,