o-Iodoxy Benzoic Acid–Mediated Synthesis of 3,5-Diarylisoxazoles and Isoxazole-3-carboxylic Acids

Abstract

A new, convenient, ecofriendly synthesis of 3,5-diarylisoxazoles is reported from α,β-unsaturated ketoximes. Similarly, a novel synthesis of isoxazole carboxylic acids is also reported. Both the methods use efficient, environmentally friendly, and nontoxic iodoxybenzoic acid (IBX) as an oxidative cyclizing reagent. Easy procedure, environmentally benign reaction conditions, and nontoxicity are advantages to the methodology.

GRAPHICAL ABSTRACT

Keywords:

• Chalcone
• isoxazoles
• o-iodoxybenzoic acid
• oxidative cyclization
• α,β-unsaturated ketoxime

Notes

^a All products were characterized by ¹H NMR, ¹³C NMR, and IR data.

^b Yields after purification by chromatography.

^c Identified by comparison with authentic samples (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 37).

^a All products were characterized by ¹H NMR, ¹³C NMR, and IR data.

^b Yields after purification by chromatography.

^c Identified by comparison with authentic samples (31, 33, 34, and 36).