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. 2011 Aug 5;76(15):5915-23.
doi: 10.1021/jo201042c. Epub 2011 Jun 27.

Synthesis of substituted pyrazoles via tandem cross-coupling/electrocyclization of enol triflates and diazoacetates

David J Babinski  1 , Hector R Aguilar, Raymond Still, Doug E Frantz
Affiliations

Synthesis of substituted pyrazoles via tandem cross-coupling/electrocyclization of enol triflates and diazoacetates

David J Babinski et al. J Org Chem. .

Abstract

The synthesis of 3,4,5-trisubstituted pyrazoles via a tandem catalytic cross-coupling/electrocyclization of enol triflates and diazoacetates is presented. The initial scope of this methodology is demonstrated on a range of differentially substituted acyclic and cyclic enol triflates as well as an elaborated set of diazoacetates to provide the corresponding pyrazoles with a high degree of structural complexity.

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Figures

Scheme 1
Scheme 1
Pericyclic Approaches to Azoles
Scheme 2
Scheme 2
Electrocyclization Strategies Towards Pyrazoles
Scheme 3
Scheme 3
Unprecedented Rearrangement of 3H-Pyrazoles
Scheme 4
Scheme 4
Diverging Sigmatropic Rearrangements of Propargyl Substituted 3H-Pyrazoles
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References

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    1. A simple online search for new patent applications to the U.S. Patent and Trademark Office involving the use of pyrazoles as therapeutic agents resulted in over 30 hits in the year 2010 alone.

    1. Selected examples of pyrazoles as potential therapeutics agents: (a) As antimicrobials: Haque TS, Tadesse S, Marcinkeviciene J, Rogers MJ, Sizemore C, Kopcho LM, Amsler K, Ecret LD, Zhan DL, Hobbs F, Slee A, Trainor GL, Stern AM, Copeland RA, Combs AP. J Med Chem. 2002;45:4669.As HMG-CoA reductase inhibitors: Pfifferkorn JA, et al. J Med Chem. 2008;51:31.As inhibitors of HIV-1 reverse transcriptase: Sweeney ZK, et al. J Med Chem. 2008;51:7449.

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