Synthesis of Pyrazoles by a One-Pot Tandem Cyclization-Dehydrogenation Approach on Pd/C/K-10 Catalyst

Shainaz M. Landge; Allison Schmidt; Verona Outerbridge; Béla Török

doi:10.1055/s-2007-982545

LETTER

Synthesis of Pyrazoles by a One-Pot Tandem Cyclization-Dehydrogenation Approach on Pd/C/K-10 Catalyst

Shainaz M. Landge, Allison Schmidt, Verona Outerbridge, Béla Török*
Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
Fax: +1(617)2876030; e-Mail: bela.torok@umb.edu;

Abstract

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Abstract

A novel one-pot synthesis of substituted pyrazoles from chalcones and hydrazines via a tandem cyclization-dehydrogenation approach is described. This process is based on the use of a bifunctional noble-metal/solid-acid catalyst, Pd/C/K-10 montmorillonite and microwave irradiation under solvent-free conditions. The cyclization of chalcones with hydrazines readily takes place on the strong solid acid while the presence of the metal ensures the formation of the aromatic product through dehydrogenation. The reactions are complete in 30 minutes providing good yields and high selectivities.

Key words

chalcones - hydrazines - bifunctional catalysis - microwave heating - pyrazoles

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References

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