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

Molecules

Andrea Mattarei¹  Lucia Biasutto¹  Federico Rastrelli¹  Spiridione Garbisa¹  Ester Marotta¹  Mario Zoratti¹ 

[1] ¹Department of Chemical Sciences, Università di Padova, via Marzolo 1, 35131 Padova, Italy ²Department of Biomedical Sciences, Università di Padova, viale G. Colombo 3, 35121 Padova, Italy ³CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy

关键词: regioselective alkylation;    mitochondrial targeting;    quercetin;    rhamnetin;    polyphenols;   

DOI  :  10.3390/molecules15074722

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.