Iodobenzene-Catalyzed Synthesis of Fully Functionalized NH-Pyrazoles and Isoxazoles from α,β-Unsaturated Hydrazones and Oximes via 1,2-Aryl Shift
Vikram Singh, Deepak Kumar, Bal Krishna Mishra, Bhoopendra Tiwari*
*Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India,
Email: btiwari
cbmr.res.in
V. Singh, D. Kumar, B. K. Mishra, B. Tiwari, Org. Lett., 2024, 26, 385-389.
DOI: 10.1021/acs.orglett.3c04057
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Abstract
An iodine(III)-catalyzed synthesis of fully functionalized NH-pyrazoles and isoxazoles from α,β-unsaturated hydrazones and oximes, respectively, includes cyclization, 1,2-aryl shift, aromatization, and detosylation. The reaction gives direct access to an advanced intermediate for the preparation of valdecoxib and parecoxib, drugs used for COX-inhibition.
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proposed mechanism
Key Words
ID: J54-Y2024
