Molecules 2007, 12(7), 1482-1495; doi:10.3390/12071482
Article

New “Green” Approaches to the Synthesis of Pyrazole Derivatives

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Received: 31 May 2007; in revised form: 16 July 2007 / Accepted: 16 July 2007 / Published: 19 July 2007
(This article belongs to the Special Issue Heterocycles)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: A novel approach to the synthesis of pyrazole derivatives from tosylhydrazones of α,β-unsaturated carbonyl compounds possessing a β-hydrogen is proposed, exploiting microwave (MW) activation coupled with solvent free reaction conditions. The cycloaddition was studied on three ketones (trans-4-phenyl-3-buten-2-one, β-ionone and trans-chalcone). The corresponding 3,5-disubstitued-1H-pyrazoles were obtained in high yields and after short reaction times. In order to simplify and point out the green chemistry features of the method, a further improvement was achieved under the same catalytic conditions with a “one pot” synthesis of these heterocyclic compounds, starting directly from their carbonyl precursors via tosylhydrazones generated in situ. For an exhaustive study, the dielectric properties of the solid reaction mixtures were also measured, in order to obtain input data for the numerical simulation of their heating behaviour in the single mode MW cavity which was used for experimental work. In order to supply a valid methodology and tool for measuring the environmental impact, a comparative study between the synthetic route proposed and the classical synthetic route has been carried out.
Keywords: Pyrazole derivatives; solvent free cycloaddition; microwaves
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MDPI and ACS Style

Corradi, A.; Leonelli, C.; Rizzuti, A.; Rosa, R.; Veronesi, P.; Grandi, R.; Baldassari, S.; Villa, C. New “Green” Approaches to the Synthesis of Pyrazole Derivatives. Molecules 2007, 12, 1482-1495.

AMA Style

Corradi A, Leonelli C, Rizzuti A, Rosa R, Veronesi P, Grandi R, Baldassari S, Villa C. New “Green” Approaches to the Synthesis of Pyrazole Derivatives. Molecules. 2007; 12(7):1482-1495.

Chicago/Turabian Style

Corradi, Anna; Leonelli, Cristina; Rizzuti, Antonino; Rosa, Roberto; Veronesi, Paolo; Grandi, Romano; Baldassari, Sara; Villa, Carla. 2007. "New “Green” Approaches to the Synthesis of Pyrazole Derivatives." Molecules 12, no. 7: 1482-1495.

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