- Investigating the microwave-accelerated Claisen rearrangement of allyl aryl ethers: Scope of the catalysts, solvents, temperatures, and substrates
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The microwave-accelerated Claisen rearrangement of allyl aryl ethers was investigated, in order to gain insight into the scope of the catalysts, solvents, temperatures, and substrates. Among the catalysts examined, phosphomolybdic acid (PMA) was found to greatly accelerate the reaction in NMP, at temperatures ranging from 220 to 300 °C. This method was found to be useful for preparing several intermediates previously reported in the literature using precious metal catalysts such as Au(I), Ag(I), and Pt(II). Additionally, substrates bearing bromo and nitro groups on the aryl portion required careful tailoring of the reaction conditions to avoid complex product profiles.
- Hui, Zi,Jiang, Songwei,Qi, Xiang,Ye, Xiang-Yang,Xie, Tian
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- Method for preparing hydrocarbyl phenol by catalytic conversion of phenolic compound in presence of molybdenum-based catalyst
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The invention discloses a method for preparing hydrocarbyl phenol by catalytic conversion of a phenolic compound in the presence of a molybdenum-based catalyst. The method comprises mixing a phenoliccompound, a molybdenum-based catalyst and a reaction solvent, adding the mixture into a sealed reactor, feeding gas into the reactor, heating the mixture to 150-350 DEG C, carrying out stirring for areaction for 0.5-2h, then filtering to remove a solid catalyst and carrying out rotary evaporateion to obtain a liquid product. The phenolic compound has a wide source, a cost is low, product alkyl phenol selectivity is high, an added value is high, alcohol or an alcohol-water mixture is used as a reaction solvent, environmental friendliness is realized, pollution is avoided, any inorganic acids and alkalis are avoided in the reaction process, the common environmental pollution problems in the biomass processing technology are solved, the reaction conditions are mild, the process can be carried out at a low temperature, high-efficiency conversion of the reactants can be realized without consuming hydrogen gas and the method is suitable for large-scale industrial trial production.
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Paragraph 0046; 0070
(2018/04/02)
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- Method for compounding benzofuran derivatives by adding C-O bonds into olefin molecules through non-metallic Lewis acid catalysis
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The invention provides a method for compounding benzofuran derivatives by adding C-O bonds into olefin molecules through non-metallic Lewis acid catalysis. The method includes step 1, subjecting raw materials, namely phenol derivatives, to three-step reactions to obtain olefin serving as a reaction substrate; step 2, adding non-metallic Lewis acid and methylbenzene into the reaction substrate obtained in the step 1, and obtaining the benzofuran derivatives after reaction. The method has the advantages that the non-metallic Lewis acid is taken as a catalyst during reaction, so that pollution ofresidual metal catalysts to products is avoided, and troubles in post-treatment are omitted.
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- Development and Mechanistic Study of Quinoline-Directed Acyl C-O Bond Activation and Alkene Oxyacylation Reactions
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The intramolecular addition of both an alkoxy and acyl substituent across an alkene, oxyacylation of alkenes, using rhodium catalyzed C-O bond activation of an 8-quinolinyl ester is described. Our unsuccessful attempts at intramolecular carboacylation of ketones via C-C bond activation ultimately informed our choice to pursue and develop the intramolecular oxyacylation of alkenes via quinoline-directed C-O bond activation. We provide a full account of our catalyst discovery, substrate scope, and mechanistic experiments for quinoline-directed alkene oxyacylation.
- Hoang, Giang T.,Walsh, Dylan J.,McGarry, Kathryn A.,Anderson, Constance B.,Douglas, Christopher J.
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p. 2972 - 2983
(2017/03/23)
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- Pd-Catalyzed regioselective hydroesterification of 2-allylphenols to seven-membered lactones without external CO gas
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Effective Pd-catalyzed regioselective hydroesterification of 2-allylphenols with phenyl formate is described. A variety of seven-membered lactones can be obtained in good yields under mild conditions without the use of toxic CO gas.
- Chang, Wenju,Li, Jingfu,Ren, Wenlong,Shi, Yian
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supporting information
p. 3047 - 3052
(2016/03/19)
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- Improved and scalable synthesis of building blocks for the modular synthesis of teraryl-based alpha-helix mimetics
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The modular synthesis of teraryl-based alpha-helix mimetics can be accomplished by sequential Suzuki-couplings of arylboronic acid building blocks with 4-iodophenyltriflate core-fragments. We report about new synthetic accesses to core fragments featuring
- Trobe, Melanie,Breinbauer, Rolf
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p. 509 - 521
(2016/03/19)
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- Insertion of an Alkene into an ester: Intramolecular oxyacylation reaction of alkenes through acyl C-O bond activation
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Atom economy and esters: compatible now! The first catalytic insertion of a C-C bond into an acyl C-O bond was achieved using rhodium catalysts (see scheme). The products are β-alkoxy ketones with a fully substituted carbon center. Quinoline chelating groups were employed to stabilize the Rh-alkoxide intermediate.
- Hoang, Giang T.,Reddy, Venkata Jaganmohan,Nguyen, Huy H. K.,Douglas, Christopher J.
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supporting information; scheme or table
p. 1882 - 1884
(2011/04/16)
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- Pd-Catalyzed intramolecular oxyalkynylation of alkenes with hypervalent iodine
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(Figure presented) The first example of intramolecular oxyalkynylation of nonactivated alkenes using oxidative Pd chemistry is reported. Both phenol and aromatic or aliphatic acid derivatives could be used under operator-friendly conditions (room temperature, technical solvents, under air). The discovery of the superiority of benzlodoxolone-derlved hypervalent iodine reagent 3d as an alkyne transfer reagent further expands the rapidly increasing utility of hypervalent iodine reagents in catalysis and is expected to have important implications for other similar processes.
- Nicolal, Stefano,Erard, Stephane,Gonzalez, Davinla Fernandez,Waser, Jerome
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supporting information; experimental part
p. 384 - 387
(2010/03/04)
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- Regio- and stereoselective copper-induced isomerization of 2-alkenyl 2-lithiophenyl ethers to 2-(2-alkenyl)phenols
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N-Allyl-N-(2-lithioallyl)aniline undergoes intramolecular carbometallation via 5-exo addition on treatment with CuCN. 2-Alkenyl 2-bromophenyl ethers rearrange to 2-(2-alkenyl)phenols by bromine-lithium exchange and further transmetallation with CuCN.
- Barluenga, Jose,Sanz, Roberto,Fananas, Francisco J.
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p. 6103 - 6106
(2007/10/03)
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- -SIGMATROPIC REARRANGEMENTS OF THE ACETOACETATES OF ALLYL ALCOHOLS (CARROLL REACTION) AND ALLYLPHENYL ETHERS (CLAISEN REACTION) ON THE SURFACE OF ADSORBENTS
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A method has been developed for effecting rearrangements of allylacetoacetates to γ,δ-unsaturated ketones (Carroll rearrangement) and allylaryl ethers to the corresponding allylphenols (Claisen rearrangement) under conditions of adsorption on aluminum oxide and silica gel.The method provides a sharp reduction of the temperature of these reactions and improvement of their efficiency.
- Pogrebnoi, S. I.,Kal'yan, Yu. B.,Krimer, M. Z.,Smit, V. A.
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p. 733 - 739
(2007/10/02)
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- α-Adrenoreceptor Reagents. 2. Effects of Modification of the 1,4-Benzodioxan Ring System on α-Adrenoreceptor Activity
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Modification of the 1,4-benzodioxan ring present in RX 781094 (1) has not previously been considered.This paper describes a number of analogues of this ring system, including compounds in which one of the oxygen atoms has been replaced by a methylene group and also those in which the ring size has been changed to give, for example, furan and thiophene derivatives.The dihydroxybenzofuranylimidazoline compound 7 is the only analogue possesing presynaptic antagonist potency and selectivity comparable to that of 1.In view of this result, a number of derivatives was prepared to determine the structure-activity relationships within this series.Many derivatives, as well as the parent compound 7, were found to possess presynaptic α2-adrenoreceptor antagonist and postsynaptic α1-adrenoreceptor partial agonist properties.Two of the selective presynaptic antagonists,13 and 14, possess greater potency and selectivity than that possessed by 1.The 5-chloro derivative 25 is twice as potent as 1 after oral administration but only about half as potent when given intravenously.
- Chapleo, Christopher B.,Myers, Peter L.,Butler, Richard C. M.,Davis, John A.,Doxey, John C.,et al.
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p. 570 - 576
(2007/10/02)
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