19578-70-2Relevant articles and documents
Synergism of low energy microwave irradiation and solid-liquid phase transfer catalysis for selective alkylation of phenols to phenolic ethers
Yadav, Ganapati D.,Bisht, Priyal M.
, p. 2885 - 2892 (2004)
A 100% selectivity with an order of magnitude rate enhancement is obtained in the synthesis of phenolic ethers when synergistic combination of solid-liquid phase transfer catalysis and low energy microwave irradiation (MISL-PTC) is employed. As against conventional microwave heating with 600 W power input, the current work demonstrates that a low input of 40 W leads to remarkable enhancement in rates without any destruction of the catalyst.
Towards ortho-selective electrophilic substitution/addition to phenolates in anhydrous solvents
Lopu?anskaja, Eleana,Kooli, Anni,Paju, Anne,J?rving, Ivar,Lopp, Margus
, (2021/02/16)
Alkyl-substituted Li-phenolates with BnBr in water solution lead to a mixture of o- and p-Bn-substituted phenols together with a substantial amount of phenol Bn ether. In CPME, and especially in toluene with 1–2 equivalents of ether or alcohol additives, ortho-selective alkylation is achieved. In the case of o,o,p-tri- and o,o-di-substituted phenols dearomatization occurs affording o-Bn-substituted alkyl cyclohexadienones with yields up to 92% with an o/p ratio up to 90/1.
Choline Hydroxide as a Versatile Medium for Catalyst-Free O-Functionalization of Phenols
Joo, Seong-Ryu,Kim, Seung-Hoi,Kwon, Gyu-Tae,Park, Soo-Youl
, p. 1200 - 1205 (2020/11/30)
A versatile synthetic protocol for benzyl phenyl ether preparation via O-alkylation of phenolic oxygen with readily available benzyl derivatives was demonstrated. The newly designed procedure was carried out using an eco-friendly medium, room-temperature ionic liquid (choline hydroxide), under metal- and base-catalyst-free aerobic conditions. The reaction platform was also successfully applied to phenol protection strategy.
An alternative route for boron phenoxide preparation from arylboronic acid and its application for C[sbnd]O bond formation
Joo, Seong-Ryu,Kim, Seung-Hoi,Lim, In-Kyun
, (2020/08/06)
An efficient synthetic route to benzyl phenyl ether preparation has been successfully developed via a one-pot synthetic protocol utilizing a combination of arylboronic acids, hydrogen peroxide (H2O2), and benzyl halides. The whole procedure consists of two consecutive reactions, formation of boron phenoxide from arylboronic acids and its nucleophilic attack. A simple operation under mild conditions such as room-temperature ionic liquid (choline hydroxide), aerobic environment, and absence of metal- and base-catalysts has been employed. Expansion to utilize benzyl surrogates was also successfully accomplished.
Control of tandem isomerizations: Flow-assisted reactions of: O -lithiated aryl benzyl ethers
Lee, Hyune-Jea,Kim, Heejin,Yoshida, Jun-Ichi,Kim, Dong-Pyo
supporting information, p. 547 - 550 (2018/01/19)
Tandem chemical changes are often difficult to control at will, because they proceed rapidly through multiple unstable reactive intermediates. It is desirable to develop a novel method for controlling such tandem changes to obtain desired products with high selectivity. Herein, we report a flow microreactor platform for controlling tandem isomerizations of o-lithiated aryl benzyl ethers based on precise residence time control.
Tetrabutyl ammonium bromide-mediated benzylation of phenols in water under mild condition
Wang, Hailei,Ma, Yuping,Tian, Heng,Yu, Ajuan,Chang, Junbiao,Wu, Yangjie
, p. 2669 - 2673 (2014/04/03)
Benzylation of phenol was successfully achieved in water under room temperature mediated by tetrabutylammonium bromide (TBAB) for only 2 h affording the corresponding benzyl phenyl ether with good to excellent yields. This protocol is very efficient, simple, avoiding catalysts, easy to work-up after reaction, and especially 'green'.
C,N-chelated organotin(IV) compounds as catalysts for transesterification and derivatization of dialkyl carbonates
Weidlich, Tomas,Dusek, Libor,Vystrcilova, Barbora,Eisner, Ales,Svec, Petr,Ruzicka, Ales
, p. 293 - 300 (2012/10/07)
The potential catalytic activity of selected C,N-chelated organotin(IV) compounds (e.g. halides and trifluoroacetates) for derivatization of both dimethyl carbonate (DMC) and diethyl carbonate (DEC) was investigated. Some tri-, di- and monoorganotin(IV) species (LCN(n-Bu)2SnCl (1), LCN(n-Bu)2SnCl.HCl (1a), LCN(n-Bu) 2SnI (2), LCNPh2SnCl (3), LCNPh 2SnI (4), LCN(n-Bu)SnCl2 (5), L CNSnBr3 (6) and [LCNSn(OC(O)CF 3)]2(μ-O)(μ-OC(O)CF3)2 (7)) bearing the LCN moiety (LCN = 2-(N,N-dimethylaminomethyl) phenyl-) were assessed as catalysts for reactions of both DMC and DEC with various substituted anilines. The catalytic activities of 4 and 7 for derivatization of DMC with p-substituted phenols were studied for comparison with the standard base K2CO3/Silcarbon K835 catalyst (catalyst 8). The composition of resulting reaction mixtures was monitored by multinuclear NMR spectroscopy, GC and GC-MS techniques. In general, catalysts 1, 3 and 7 exhibited the highest catalytic activity for all reactions studied, while some of them yielded selectively carbonates, carbamates, lactam or substituted urea. Copyright
Ti-catalyzed homolytic opening of ozonides: A sustainable C-C bond-forming reaction
Rosales, Antonio,Munoz-Bascon, Juan,Lopez-Sanchez, Cristobal,Alvarez-Corral, Miriam,Munoz-Dorado, Manuel,Rodriguez-Garcia, Ignacio,Oltra, J. Enrique
experimental part, p. 4171 - 4176 (2012/06/18)
The unprecedented homolytic opening of ozonides promoted and catalyzed by titanocene(III) is reported. This novel reaction proceeds at room temperature under neutral, mild conditions compatible with many functional groups and provides carbon radicals suitable to form C-C bonds via both homocoupling and cross-coupling processes. The procedure has been advantageously exploited for the straightforward synthesis of the natural product brittonin A.
A general and efficient catalyst for palladium-catalyzed C-O coupling reactions of aryl halides with primary alcohols
Gowrisankar, Saravanan,Sergeev, Alexey G.,Anbarasan, Pazhamalai,Spannenberg, Anke,Neumann, Helfried,Beller, Matthias
supporting information; experimental part, p. 11592 - 11598 (2010/10/02)
An efficient procedure for palladium-catalyzed coupling reactions of (hetero)aryl bromides and chlorides with primary aliphatic alcohols has been developed. Key to the success is the synthesis and exploitation of the novel bulky di-1-adamantyl-substituted bipyrazolylphosphine ligand L6. Reaction of aryl halides including activated, nonactivated, and (hetero)aryl bromides as well as aryl chlorides with primary alcohols gave the corresponding alkyl aryl ethers in high yield. Noteworthy, functionalizations of primary alcohols in the presence of secondary and tertiary alcohols proceed with excellent regioselectivity.
Ginger and its bioactive component inhibit enterotoxigenic Escherichia coli heat-labile enterotoxin-induced diarrhea in mice
Chen, Jaw-Chyun,Huang, Li-Jiau,Wu, Shih-Lu,Kuo, Sheng-Chu,Ho, Tin-Yun,Hsiang, Chien-Yun
experimental part, p. 8390 - 8397 (2009/09/29)
Ginger is one of the most commonly used fresh herbs and spices. Enterotoxigenic Escherichia coli heat-labile enterotoxin (LT)-induced diarrhea is the leading cause of infant death in developing countries. In this study, we demonstrated that ginger significantly blocked the binding of LT to cell-surface receptor GM1, resulting in the inhibition of fluid accumulation in the closed ileal loops of mice. Biological-activity-guided searching for active components showed that zingerone (vanillylacetone) was the likely active constituent responsible for the antidiarrheal efficacy of ginger. Further analysis of chemically synthesized zingerone derivatives revealed that compound 31 (2-[(4-methoxybenzyl)oxy]benzoic acid) significantly suppressed LT-induced diarrhea in mice via an excellent surface complementarity with the B subunits of LT. In conclusion, our findings provide evidence that ginger and its derivatives may be effective herbal supplements for the clinical treatment of enterotoxigenic Escherichia coli diarrhea.
