Unveiling the chemistry behind bromination of quercetin: the ‘violet chromogen’

Autor:	Mario C. Foti, Concetta Rocco
Rok vydání:	2014
Předmět:	Aqueous solution Bromine Organic Chemistry chemistry.chemical_element Regioselectivity Halogenation Photochemistry Biochemistry NMR spectra database chemistry.chemical_compound Deprotonation chemistry Drug Discovery Electrophile Methanol
Zdroj:	Tetrahedron Letters. 55:1602-1607
ISSN:	0040-4039
DOI:	10.1016/j.tetlet.2014.01.081
Popis:	Bromination of quercetin with N-bromosuccinimide in neutral aqueous methanol occurs surprisingly in the electron-deficient A-ring only. Deprotonation of the acidic 7-OH is a major driver of this regioselective reaction. The increase of electron density makes in fact the quercetin anion suitable for an electrophilic attack by bromine at positions 8 and 6. Several pieces of evidence (NMR spectra and H/D exchange) are presented to substantiate the mechanism advanced. Bromoquinones/quinomethides produced in excess of N-bromosuccinimide are responsible for the formation of a stable ‘violet chromogen’.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::a7f30c9652372dd1259b046c29f832dd https://doi.org/10.1016/j.tetlet.2014.01.081 Zobrazit plný text záznamu Full Text from ScienceDirect