Reaction of quercetin (QR) (1) with bromine under various conditions was studied. Interaction of QR with 2-3 equiv. of bromine in glacial acetic acid at 35-40°C for 2-4 h and 20-22°C for 24 h led to the formation of QR 6,8-dibromide (2) (52-54% yields, 96-98% purity by HPLC). Interaction of QR with 2-5 equiv. bromine in absolute ethanol at 0-5°C and 20-22°C for 24 h led to the formation of 3-O-ethyl-QR-2,3,6,8,5'-pentabromide (3) (95-97% purity by HPLC) the output of which depends on the quantity of bromine. It was shown in MDCK cell culture that compound 2 exhibits a moderate inhibitory activity against pandemic influenza virus A/H1N1/pdm09 (EC50 6.0 µg/mL, CTD50 97.7 µg/mL, SI 16). Compound 3 was inactive.
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J Org Chem
October 2024
Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany.
Herein, we describe the investigation of electrochemical bromination of electron-rich arenes in a 200% cell. For this application, at first, the influence of an excess of supporting electrolyte (BuNBr) on chemical bromination was investigated. The application of >4.
View Article and Find Full Text PDFJ Am Chem Soc
October 2023
State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin 300071, People's Republic of China.
The synthesis, structures, and reactivity of the first neutral 2π-aromatic Si rings [LSiSiAr(X)] (: X = Br; : X = Cl; L = PhC(NBu), Ar = 2,4,6-MeCH) were described. Compounds and were obtained by 1,3-halogenation of tetrasilacyclobutadiene (LSiSiAr) (), which was prepared by the reductive cross-coupling of trisilane (ArSiCl)SiHAr with two equiv of chlorosilylene LSiCl. The reaction of with two equiv of PhLi yielded the corresponding substitution Si ring [LSiSiAr(Ph)] ().
View Article and Find Full Text PDFJ Org Chem
July 2023
Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Senbaru 1, Nakagami, Nishihara 903-0213, Okinawa, Japan.
Herein, we report the highly enantioselective α-fluorination of both cyclic and acyclic β-dicarbonyl compounds, including β-diketones, β-ketoesters, and β-ketoamides. The reactions with β,β-diaryl serines as primary amine organocatalysts were enhanced by adding alkali carbonates, such as NaCO or LiCO, and enabled the reaction to be conducted with only 1.1 equiv of Selectfluor.
View Article and Find Full Text PDFInorg Chem
June 2023
Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
The oxidative chlorination of the plutonium metal was achieved through a reaction with gallium(III) chloride (GaCl). In DME (DME = 1,2-dimethoxyethane) as the solvent, substoichiometric (2.8 equiv) amounts of GaCl were added, which consumed roughly 60% of the plutonium metal over the course of 10 days.
View Article and Find Full Text PDFBeilstein J Org Chem
August 2022
Department of Chemistry, BITS Pilani, K. K. Birla Goa Campus, Goa 403 726, India.
A simple electrical mortar-pestle was used for the development of a green and facile mechanochemical route for the catalyst-free halogenation of phenols and anilines via liquid-assisted grinding using PEG-400 as the grinding auxiliary. A series of mono-, di-, and tri-halogenated phenols and anilines was synthesized in good to excellent yields within 10-15 min in a chemoselective manner by controlling the stoichiometry of -halosuccinimides (NXS, X = Br, I, and Cl). It was observed that PEG-400 plays a key role in controlling the reactivity of the substrates and to afford better regioselectivity.
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