Assembly of Pyrano[2,3-c]pyrazol-5-ol from Electron-Deficient Bifunctional Peroxides via Michael
Jiaxu Feng1,2, Yingying Wu1, Yuze Cui1
1Department of Chemistry, College of Sciences, Tianjin University of Science and Technology, Tianjin 300457, People's Republic of China.
None:
A base-mediated formal [3+3] annulation between electron-deficient bifunctional peroxides and pyrazolones was disclosed, delivering various pyrano[2,3-c]pyrazol-5-ols in good yields. This cascade annulation method exhibits mild conditions and good substrate tolerance. Preliminary mechanistic studies and DFT calculations provide strong evidence supporting the Michael addition/cyclization/ring-opening process. In vitro cytotoxicity experiments reveal that this simple protocol establishes a useful framework for synthesizing potential candidate molecules of antitumor drugs.
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