644-35-9Relevant academic research and scientific papers
Ortho-selective alkylation of phenol with 1-propanol catalyzed by CeO2-MgO
Sato, Satoshi,Takahashi, Ryoji,Sodesawa, Toshiaki,Matsumoto, Kotaro,Kamimura, Yoichiro
, p. 180 - 188 (1999)
Vapor-phase alkylation of phenol with 1-propanol was investigated over CeO2-MgO catalysts prepared utilizing a molten mixture of the corresponding nitrates and citric acid. The CeO2-MgO had a stable catalytic activity at 475°C, and had an excellent selectivity to 2-propylphenol, higher than 82% based on phenol. Although a portion of the 2-propylphenol produced was decomposed into o-cresol and 2-ethylphenol, a sum of selectivities to the monoalkylated phenols exceeded 97%. During the alkylation, propanal and 3-pentanone was observed. In the results of 1-propanol conversion without phenol, it was found that 1-propanol was dehydrogenated to propanal and that the propanal produced was dimerized to 3-hydroxy-2-methylpentanal via aldol addition, followed by the deformylation into 3-pentanone. Namely, in the reaction of phenol and 1-propanol, the propylation of phenol and the dehydrogenation of 1-propanol occurred concurrently over the CeO2-MgO. The pure CeO2, having both the redox property with Ce4+-Ce3+ and weak basic sites, catalyzed both the propylation of phenol and the 1-propanol transformation into 3-pentanone, while the pure MgO with strong basicity was less active for the 1-propanol transformation and had a low reaction rate in the alkylation. The reaction mechanism of the ortho-propylation over the CeO2-MgO catalyst is speculated as follows. The ortho position of phenol adsorbed perpendicularly on weak basic sites of the catalyst is selectively alkylated by 1-propanol, which is possibly activated in the form of 1-hydroxypropyl radical on CeO2 species rather than as a form of n-propyl cation. The redox property of CeO2 is probably attributed to the homolitic activation of 1-propanol to produce 1-hydroxypropyl radical.
Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
supporting information, p. 18591 - 18598 (2021/06/28)
A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
CATALYTIC FUNNELING OF PHENOLICS
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Paragraph 0034; 0089-0090; 0167, (2021/04/30)
In general, present invention concerns an integrated wood-to-xylochemicals biorefinery, enabling production of renewable phenol, phenolic oligomers, propylene, and carbohydrate pulp from lignocellulosic biomass.
Aromatic C?H Hydroxylation Reactions with Hydrogen Peroxide Catalyzed by Bulky Manganese Complexes
Masferrer-Rius, Eduard,Borrell, Margarida,Lutz, Martin,Costas, Miquel,Klein Gebbink, Robertus J. M.
, p. 3783 - 3795 (2021/03/09)
The oxidation of aromatic substrates to phenols with H2O2 as a benign oxidant remains an ongoing challenge in synthetic chemistry. Herein, we successfully achieved to catalyze aromatic C?H bond oxidations using a series of biologically inspired manganese catalysts in fluorinated alcohol solvents. While introduction of bulky substituents into the ligand structure of the catalyst favors aromatic C?H oxidations in alkylbenzenes, oxidation occurs at the benzylic position with ligands bearing electron-rich substituents. Therefore, the nature of the ligand is key in controlling the chemoselectivity of these Mn-catalyzed C?H oxidations. We show that introduction of bulky groups into the ligand prevents catalyst inhibition through phenolate-binding, consequently providing higher catalytic turnover numbers for phenol formation. Furthermore, employing halogenated carboxylic acids in the presence of bulky catalysts provides enhanced catalytic activities, which can be attributed to their low pKa values that reduces catalyst inhibition by phenolate protonation as well as to their electron-withdrawing character that makes the manganese oxo species a more electrophilic oxidant. Moreover, to the best of our knowledge, the new system can accomplish the oxidation of alkylbenzenes with the highest yields so far reported for homogeneous arene hydroxylation catalysts. Overall our data provide a proof-of-concept of how Mn(II)/H2O2/RCO2H oxidation systems are easily tunable by means of the solvent, carboxylic acid additive, and steric demand of the ligand. The chemo- and site-selectivity patterns of the current system, a negligible KIE, the observation of an NIH-shift, and the effectiveness of using tBuOOH as oxidant overall suggest that hydroxylation of aromatic C?H bonds proceeds through a metal-based mechanism, with no significant involvement of hydroxyl radicals, and via an arene oxide intermediate. (Figure presented.).
Preparation method of alkyl aromatic compound based on alkenyl ether Friedel-Crafts reaction
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Paragraph 0042-0044; 0055-0057, (2020/07/24)
The invention discloses a preparation method of an alkyl aromatic compound based on an alkenyl ether Friedel-Crafts reaction, and belongs to the technical field of pharmaceutical and chemical intermediates and related chemistry. According to the method, alkenyl ether and an aromatic compound are used as raw materials, and green and efficient synthesis of the alkyl-substituted aromatic compound isrealized under the catalytic action of Lewis acid or protonic acid. The method has the advantages of high selectivity, mild reaction conditions, good functional group compatibility, the wide substraterange, environmental friendliness and the like. The alkyl-substituted aromatic compound is an important organic synthesis intermediate and has very wide application in the fields of organic synthesisand pharmacy, so that the alkyl-substituted aromatic compound has relatively high application value and social and economic benefits.
Synthesis of Highly Substituted Phenols and Benzenes with Complete Regiochemical Control
Zhang, Xiaojie,Beaudry, Christopher M.
supporting information, p. 6086 - 6090 (2020/08/12)
Substituted phenols are requisite molecules for human health, agriculture, and diverse synthetic materials. We report a chemical synthesis of phenols, including penta-substituted phenols, that accommodates programmable substitution at any position. This method uses a one-step conversion of readily available hydroxypyrone and nitroalkene starting materials to give phenols with complete regiochemical control and in high chemical yield. Additionally, the phenols can be converted into highly and even fully substituted benzenes.
Hydrogenation reaction method
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Paragraph 0034; 0097-0100, (2020/05/14)
The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
supporting information, p. 4119 - 4129 (2020/08/10)
A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
Benzylic C?H Functionalisation by [Et3SiH+KOtBu] leads to Radical Rearrangements in o-tolyl Aryl Ethers, Amines and Sulfides
Arokianathar, Jude N.,Kolodziejczak, Krystian,Bugden, Frances E.,Clark, Kenneth F.,Tuttle, Tell,Murphy, John A.
supporting information, p. 2260 - 2267 (2020/05/06)
Reaction of Et3SiH+KOtBu with diaryl ethers, sulfides and amines that feature an ortho alkyl group leads to rearrangement products. The rearrangements arise from formation of benzyl radicals, likely formed through hydrogen atom abstraction by triethylsilyl radicals. The rearrangements involve cyclisation of the benzyl radical onto the partner arene, which, from computation, is the rate determining step. In the case of diaryl ethers, Truce-Smiles rearrangements arise from radical cyclisations to form 5-membered rings, but for diarylamines, cyclisations to form dihydroacridines are observed. (Figure presented.).
Synthesis of bisphenol neolignans inspired by honokiol as antiproliferative agents
Cardullo, Nunzio,Barresi, Vincenza,Muccilli, Vera,Spampinato, Giorgia,D’Amico, Morgana,Condorelli, Daniele Filippo,Tringali, Corrado
, (2020/02/18)
Honokiol (2) is a natural bisphenol neolignan showing a variety of biological properties, including antitumor activity. Some studies pointed out 2 as a potential anticancer agent in view of its antiproliferative and pro-apoptotic activity towards tumor cells. As a further contribution to these studies, we report here the synthesis of a small library of bisphenol neolignans inspired by honokiol and the evaluation of their antiproliferative activity. The natural lead was hence subjected to simple chemical modifications to obtain the derivatives 3–9; further neolignans (12a-c, 13a-c, 14a-c, and 15a) were synthesized employing the Suzuki–Miyaura reaction, thus obtaining bisphenols with a substitution pattern different from honokiol. These compounds and the natural lead were subjected to antiproliferative assay towards HCT-116, HT-29, and PC3 tumor cell lines. Six of the neolignans show GI50 values lower than those of 2 towards all cell lines. Compounds 14a, 14c, and 15a are the most effective antiproliferative agents, with GI50 in the range of 3.6–19.1 μM, in some cases it is lower than those of the anticancer drug 5-fluorouracil. Flow cytometry experiments performed on these neolignans showed that the inhibition of proliferation is mainly due to an apoptotic process. These results indicate that the structural modification of honokiol may open the way to obtaining antitumor neolignans more potent than the natural lead.
