Molecules 2010, 15(7), 4722-4736; doi:10.3390/molecules15074722
Article

Regioselective O-Derivatization of Quercetin via Ester Intermediates. An Improved Synthesis of Rhamnetin and Development of a New Mitochondriotropic Derivative

Received: 10 June 2010; in revised form: 22 June 2010 / Accepted: 2 July 2010 / Published: 6 July 2010
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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: The regioselective synthesis of several quercetin (3,3’,4’,5,7-pentahydroxy flavone) tetraesters bearing a single free OH on 5-C was achieved in good yield by proper choice of reaction conditions using common esterification procedures. Tetracetylated quercetin with the free OH on 7-C was selectively obtained instead via imidazole-promoted deacylation of the corresponding pentaester. Unambiguous structural characterization of the two isomeric tetraacetyl quercetin derivatives was obtained by combined HSQC and HMBC 2D-NMR analysis. These molecules can be used as starting materials for the regioselective synthesis of other derivatives. High yield syntheses of the natural polyphenol rhamnetin (7-O-methylquercetin) and of the new mitochondriotropic compound 7-(4-triphenylphosphoniumbutyl) quercetin iodide are reported as examples.
Keywords: regioselective alkylation; mitochondrial targeting; quercetin; rhamnetin; polyphenols
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MDPI and ACS Style

Mattarei, A.; Biasutto, L.; Rastrelli, F.; Garbisa, S.; Marotta, E.; Zoratti, M.; Paradisi, C. Regioselective O-Derivatization of Quercetin via Ester Intermediates. An Improved Synthesis of Rhamnetin and Development of a New Mitochondriotropic Derivative. Molecules 2010, 15, 4722-4736.

AMA Style

Mattarei A, Biasutto L, Rastrelli F, Garbisa S, Marotta E, Zoratti M, Paradisi C. Regioselective O-Derivatization of Quercetin via Ester Intermediates. An Improved Synthesis of Rhamnetin and Development of a New Mitochondriotropic Derivative. Molecules. 2010; 15(7):4722-4736.

Chicago/Turabian Style

Mattarei, Andrea; Biasutto, Lucia; Rastrelli, Federico; Garbisa, Spiridione; Marotta, Ester; Zoratti, Mario; Paradisi, Cristina. 2010. "Regioselective O-Derivatization of Quercetin via Ester Intermediates. An Improved Synthesis of Rhamnetin and Development of a New Mitochondriotropic Derivative." Molecules 15, no. 7: 4722-4736.

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