- Convenient Approach to 3,4-Diarylisoxazoles Based on the Suzuki Cross-Coupling Reaction
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The Suzuki cross-coupling reaction was found effective for rapid access to a series of 3,4-diarylisoxazoles of pharmacological interest. The efficiency of this approach was demonstrated by the synthesis of the highly potent COX-2-selective inhibitor, 4-(5-methyl-3-phenyl-4-isoxazolyl)benzenesulfonamide (valdecoxib), and its analogues. Thus, the coupling reaction between (3-aryl-5-methyl-4-isoxazolyl)boronic acids, prepared in situ from the corresponding bromides using triisopropyl borate, and aryl bromides containing a 4-sulfonamide or 4-methylsulfonyl group under the standard conditions [Pd(PPh3)4, Na2CO3, EtOH-H2O, reflux] yielded the target 3,4-diarylisoxazoles in good yields.
- Dileep Kumar,Ho, ManKit M.,Leung, Jennifer M.,Toyokuni, Tatsushi
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p. 1146 - 1151
(2007/10/03)
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