- Contribution of microwaves in organic synthesis: Statement of a methodology for the microwave-induced preparation of benzofuran-2(3H)-one and its comparison with classical heating
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The intramolecular cyclisation of 2-hydroxyphenylacetic acid 1 into coumaran-2-one 2 was studied under both microwave irradiation and classical heating for comparison purposes. The use of a monomode oven allowed an accurate consideration of the temperature distribution in the microwave reaction vessel, which revealed a very strong and unexpected thermal heterogeneity. The reaction was facilitated by the presence of a trace of toluene-n-sulfonic acid, the catalytic role of which is demonstrated.
- Goncalo, Paulo,Roussel, Christophe,Melot, Jean Marie,Vebrel, Joel
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Read Online
- Palladium-catalyzed carbonylative synthesis of benzofuran-2(3H)-ones from 2-hydroxybenzyl alcohols using formic acid as the CO source
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A palladium-catalyzed carbonylative intramolecular synthesis of benzofuran-2(3H)-ones from 2-hydroxybenzyl alcohols has been developed. In this procedure, formic acid was utilized as the CO source, and various benzofuran-2(3H)-one derivatives were obtained in moderate to good yields.
- Li, Hao-Peng,Ai, Han-Jun,Qi, Xinxin,Peng, Jin-Bao,Wu, Xiao-Feng
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Read Online
- Pd(II)-catalyzed ortho -C-H oxidation of arylacetic acid derivatives: Synthesis of benzofuranones
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Pd(II)-catalyzed ortho-C-H acetoxylation of arylacetic acid derivatives is demonstrated with the aid of a novel S-methyl-S-2-pyridylsulfoximine (MPyS) directing group (DG). The α-mono- and α-unsubstituted arylacetic acid derivatives were readily employed in the ortho-C-H acetoxylations. The oxidation products are hydrolyzed, and the MPyS-DG is easily recovered, providing ready access to o-hydroxyarylacetic acids. 3-Mono- and 3-unsubstituted benzofuranones are synthesized from o-hydroxyarylacetic acids.
- Rit, Raja K.,Yadav, M. Ramu,Sahoo, Akhila K.
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Read Online
- Exploring the Electronic Properties of Extended Benzofuran-Cyanovinyl Derivatives Obtained from Lignocellulosic and Carbohydrate Platforms Raw Materials
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Two series of linear extended benzofuran derivatives associating cyanovinyl unit and phenyl or furan moieties obtained from benzaldehyde-lignocellulosic (Be series) or furaldehyde –saccharide (Fu series) platforms were prepared in order to investigate their emission and electrochemical properties. For the fluorescence in solution and solid states, contrasting results between the two series were demonstrated. For Be series a net aggregation induced emission effect was observed with high fluorescence quantum yield for the solid state. A [2+2] cycloaddition under irradiation at 350 nm was also revealed for one derivative of Be series. In contrast, for Fu series the fluorescence in solution is higher than in the solid state. The X-ray crystallography studies for the compounds reveal the formation of strong π-π stacking for the derivatives without emissive property in the solid state and the presence of essentially lateral contacts for emissive compounds. Taking advantage of the propensity to develop 2D π-stacking mode for the more extended derivative with a central furan cycle, organic field effect transistors presenting hole mobility have been made.
- Ibrahim, Nagham,Moussallem, Chady,Allain, Magali,Segut, Olivier,Gohier, Frédéric,Frère, Pierre
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p. 475 - 482
(2021/03/31)
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- Regioselective Synthesis of Benzofuranones and Benzofurans
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Reaction of 3-hydroxy-2-pyrones with nitroalkenes bearing ester groups gives benzofuranones. The reaction allows regioselective preparation of the benzofuranones with programmable substitution at any position. Complex substitution patterns are readily cre
- Zhang, Xiaojie,Beaudry, Christopher M.
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supporting information
p. 6931 - 6936
(2021/05/06)
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- Method for improving conversion rate of azoxystrobin
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The invention discloses a method for improving the conversion rate of azoxystrobin. The method comprises the following steps: preparing methyl (E)-2-[2-(6-chloropyrimidin-4-yloxy)phenyl]-3-methoxy acrylate; preparing o-hydroxybenzonitrile; mixing methyl (E)-2-[2-(6-chloropyrimidin-4-yloxy)phenyl]-3-methoxy acrylate, o-hydroxybenzonitrile, potassium carbonate and ketene chloride according to a molar ratio of 30: 35: 50: 1.1, and dissolving the obtained mixture in dimethylformamide to obtain a mixed product; and heating the prepared mixed product, keeping the mixed product at a certain temperature, conducting filtering, carrying out reduced-pressure distillation, performing cooling, separating out crystals, carrying out filtering and washing and performing drying to obtain azoxystrobin. On the basis of the prior art, the synthesis of azoxystrobin is improved in the invention, so the yield of azoxystrobin is effectively increased, the conversion rate of the raw materials including methyl(E)-2-[2-(6-chloropyrimidin-4-yloxy)phenyl]-3-methoxy acrylate and o-hydroxybenzonitrile for azoxystrobin in the process of preparing azoxystrobin is effectively improved, and the production benefit of azoxystrobin is improved.
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Paragraph 0066-0069
(2021/03/31)
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- Synthetic method of benzofuranone
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The invention provides a synthetic method of benzofuranone. According to the method, o-cresol which is relatively easy to obtain is used as an initial raw material, and the target product benzofuranone is prepared through four-step reaction; and the whole preparation process is mild in condition, high in yield, easy to operate, small in environmental pollution and suitable for large-scale industrial production.
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Page/Page column 8-10
(2020/06/16)
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- Method for synthesizing benzofuranone by taking O-chlorotoluene as raw material
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The invention provides a method for synthesizing benzofuranone by taking o-chlorotoluene as a raw material. According to the method, the target product benzofuranone is prepared by taking the easily-available o-chlorotoluene as the initial raw material, and the whole preparation process is mild in condition, high in yield and suitable for large-scale industrial production.
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Page/Page column 6-8
(2020/06/16)
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- Preparation method of benzofuranone (by machine translation)
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To the preparation method . o-hydroxyacetophenone as a starting material, firstly undergoes Willgerodt - Kindler reaction to obtain phenylacetic acid, and then undergoes intramolecular esterification to obtain the final product benzofuranone, the reaction yield is higher, more efficiently . and compared with the traditional synthesis method, the reaction yield is higher, operation is easy. (by machine translation)
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Paragraph 0008-0019
(2020/05/05)
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- One-step method for synthesizing benzofuranone (by machine translation)
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The synthetic method can be used for skillfully avoiding the generation of polluted by-products without adding other reactants, and is mild in reaction condition, high in yield and suitable for industrial mass production. (by machine translation)
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Paragraph 0047-0054
(2020/06/16)
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- Preparation method of benzofuran -2-(3H)- ketone (by machine translation)
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The preparation method of the benzofuran, 2-(3H)- ketone takes the phenol, as the raw material, and the α - chloroacetyl chloride in the esterification reaction to react itself to form benzofuran - Friedel - Crafts, 2 (Benzofuran-2.(3H)-one. The method greatly shortens, the reaction conditions of the reaction path which is reported in, the art and the chloroacetyl chloride . The method does, not need to add, highly toxic compound sodium cyanide to form benzofuran-2-(-(H)-one in a, simple, and easily available raw. material. The invention greatly shortens the reaction cost and has high industrial application value in the synthesis step. (by machine translation)
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Paragraph 0021; 0024-0026; 0029-0031; 0034-0036; 0039-0041
(2020/03/06)
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- Benzofuran -2 - (3 H) - ketone
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The invention discloses a benzofuran - 2 - (3 H) - one of the preparation method, is divided into two steps: (1) preparation of O-hydroxy acetic acid: in acidic conditions or under alkaline conditions, the cyclohexyl - 2 - enone, glyoxalic acid, solvent in the reactor reaction, after the completion of the reaction, the solvent is recovered, by the re-crystallization O-hydroxy acetic acid pure product; (2) benzofuran - 2 - (3 H) - ketone preparation: the belt water trap is added into the reactor in step (1) preparation of ortho-hydroxy acetic acid, then adding solid catalyst and solvent, heating reflux reaction, to no longer have a water drop, cooling to room temperature, filter, to filter the solid catalyst, pressure reducing and recovering the solvent, by recrystallization to obtain benzofuran - 2 - (3 H) - one. In the invention of the cheap raw material, the main material cyclohex - 2 - enone by cyclohexanone in the non-water system and be prepared by chlorine chloride 2 - [...], again obtained by eliminating the; a commercialization of the glyoxylic acid 50% aqueous solution, synthetic route of this invention short and simple operation, high yield, low cost, three waste is greatly reduced.
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Paragraph 0032; 0033; 0038; 0039; 0044; 0045; 0050; 0051
(2019/07/04)
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- PPh3/Selectfluor-Mediated Transformation of Carboxylic Acids into Acid Anhydrides and Acyl Fluorides and Its Application in Amide and Ester Synthesis
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By taking the advantage of PPh3/Selectfluor system, carboxylic acids are efficiently converted into the pivotal intermediates acyloxyphosphonium ions that can selectively react with a second carboxylic acid or fluoride to in situ yield the corresponding acid anhydrides or acyl fluorides. The developed protocol features commercially availabile reagents, no involvement of base, room temperature conditions, and simple experimental procedure. Additionally, various amides or esters are readily achieved, respectively, with the addition of amines or alcohols.
- Yang, Zhen,Chen, Siwei,Yang, Fang,Zhang, Chenxi,Dou, You,Zhou, Qiuju,Yan, Yizhe,Tang, Lin
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p. 5998 - 6002
(2019/08/21)
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- Palladium-catalysed ring-opening [3 + 2]-annulation of spirovinylcyclopropyl oxindole to diastereoselectively access spirooxindoles
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A novel palladium-catalysed ring-opening [3 + 2]-annulation of spirovinylcyclopropyl oxindole with α,β-unsaturated nitroalkenes is reported. A series of spirooxindole derivatives were synthesized in high yields and good to excellent diastereoselectivities. This developed protocol offers a new and efficient pathway for the assembly of spirooxindoles.
- Xiao, Jun-An,Cheng, Xiu-Liang,Li, Yu-Chun,He, Yi-Miao,Li, Jin-Lian,Liu, Zhi-Ping,Su, Wei,Xia, Peng-Ju,Yang, Hua
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supporting information
p. 103 - 107
(2019/01/22)
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- Synthesis method of benzofuran-2(3H)-one
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The invention relates to a synthesis method of benzofuran-2(3H)-one, which comprises the following steps: by using tert-butyl phenol and glyoxal as raw materials, acetic acid as a solvent and liquid acid as a catalyst, performing a synthesis reaction to obtain tert-butyl benzofuran, and carrying out tert-butyl removal reaction on the tert-butyl benzofuran to obtain the target product benzofuran-2(3H)-one. The method has the advantages of simple synthesis route, mild reaction conditions, no use of chlorine or other toxic substances, and no need of multiple acid-base neutralization, and can satisfy the requirements of discoloration and environmental protection.
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Paragraph 0028; 0031-0033; 0036-0038; 0041-0043
(2020/01/08)
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- Iron-catalyzed oxidative functionalization of C(sp3)-H bonds under bromide-synergized mild conditions
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An efficient oxidation and functionalization of C-H bonds with an inorganic-ligand supported iron catalyst and hydrogen peroxide to prepare the corresponding ketones was achieved using the bromide ion as a promoter. Preliminary mechanistic investigations indicated that the bromide ion can bind to FeMo6 to form a supramolecular species (FeMo6·2Br), which can effectively catalyze the reaction.
- Yu, Han,Zhao, Qixin,Wei, Zheyu,Wu, Zhikang,Li, Qi,Han, Sheng,Wei, Yongge
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supporting information
p. 7840 - 7843
(2019/07/12)
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- Design and synthesis of novel senkyunolide analogues as neuroprotective agents
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A class of senkyunolide analogues bearing benzofuranone fragment were designed, synthesized and evaluated for their neuroprotective effect in models of oxygen glucose deprivation (OGD) and oxidative stress. All tested compounds showed neuroprotection profile based on the cell viability assay. In particular, derivatives 1f–1i possessing furoxan-based nitric oxide releasing functionality exhibited significant biological activities in OGD models. More importantly, compound 1g containing short linker with furoxan displayed the most potent neuroprotection at the concentration of 100 μM (cell survival up to 145.2%). Besides, 1g also showed the middle level neuroprotective effect in model of oxidative stress.
- Fang, Yuanying,Wang, Rikang,Wang, Qi,Sun, Yongbing,Xie, Saisai,Yang, Zunhua,Li, Min,Jin, Yi,Yang, Shilin
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p. 668 - 672
(2018/01/27)
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- Benzobutyrolactone derivatives, synthetic method and application thereof in preparation of bactericides
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The invention discloses benzobutyrolactone derivatives, a synthetic method and application thereof in preparation of bactericides. The method comprises the following steps: taking sesquiterpene lactone pharmacophore alpha-methylene-gamma-butyrolactone as a lead compound, integrating benzofuranone pharmacophore, modifying at an alpha-methylene position, and performing directional derivative synthesis to obtain a series of alpha-alkenylene benzobutyrolactone compounds. The antibacterial activities of the compounds are determined, and two high-activity compounds with excellent industrialization development prospects are synthesized on the structure-effect basis. The compounds are used for controlling plant diseases caused by pathogenic bacteria such as wheat powdery mildew, wheat scab, take-all disease of wheat, wheat sharp eyespot, corn northern leaf blight, rice sheath blight disease, rice blast, cotton damping-off, phytoph-thora capsici leonian, botrytis cinerea, tomato leaf mould, tomato early/late blight, cucumber anthracnose, fusarium wilt of cucumber, sclerotinia rot of colza and the like.
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Paragraph 0041; 0042; 0043
(2018/04/03)
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- [(6 - Substituted - pyrimidine -4 - oxyacetyl) phenyl] -3 - methoxy methyl acrylate (by machine translation)
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The invention has the activity of inhibiting crop bacteria [(6 - substituted - pyrimidine - 4 - oxyacetyl) phenyl] - 3 - methoxy methyl acrylate, relates to the technical field of biochemistry. It has the following general structure: It is inhibiting the cucumber wilt disease, peanut pinguis bacteria, germ, galenical wheat, maize leaf spot, watermelon anthrax bacteria, donor bacteria and other applications has good activity. (by machine translation)
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Paragraph 0020; 0021
(2018/11/04)
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- (2-Benzyloxyphenyl)acetyl (BnPAc): A Participating Relay Protecting Group for Diastereoselective Glycosylation and the Synthesis of 1,2-trans Glycosyl Esters
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The (2-benzyloxyphenyl)acetyl group has been identified as a new protecting group for hydroxyl functions. Various alcohols could be easily protected with high yields, and deprotection was achieved by a relay approach using Pd/H 2 in combination with 1,8-bis(dimethylamino)naphthalene, conditions that are orthogonal to ester groups. The new protecting group is stable in glycosylation reactions demonstrating an effective neighboring group participation leading to the exclusive formation of 1,2-trans glycosides and glycosyl esters.
- Weber, Julia,Krauter, Simon,Schwarz, Theresa,Hametner, Christian,Mikula, Hannes
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p. 2265 - 2268
(2018/10/20)
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- Directed ortho-Metalation of O-Aryl N,N-Dialkylcarbamates: Methodology, Anionic ortho-Fries Rearrangement, and Lateral Metalation
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The directed ortho-lithiation reactions of O-aryl N,N-dialkylcarbamates as well as O-1-naphthyl and O-2-naphthyl N,N-dialkylcarbamates with sec-butyllithium/tetramethylethylenediamine (sBuLi/TMEDA) followed by quenching with various electrophiles afford a range of polysubstituted aromatic compounds. If the solutions of the ortho-lithiated carbamates are warmed to room temperature without the addition of external electrophiles, salicylamide and 1- and 2-hydroxynaphthamide derivatives are formed through anionic ortho-Fries rearrangements. The relative stabilities and reactivities of different O-aryl N,N-dialkylcarbamates were investigated. The lateral metalation of 2-tolyl carbamates with lithium diisopropylamide (LDA) provides a route to benzo[b]furan-2(3H)-ones. Previously reported results are used in a comparison of seven O-based directed metalation groups in reactions with several electrophiles. The described methodology is useful for the preparation of 1,2,3-substituted aromatic compounds.
- Miah, M. A. Jalil,Sibi, Mukund P.,Chattopadhyay,Familoni, Oluwole B.,Snieckus, Victor
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p. 440 - 446
(2017/12/15)
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- Synthetic method of benzofuran-2(3H)-one
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The invention discloses a synthetic method of benzofuran-2(3H)-one. The method comprises the following steps: hydrolyzing o-clorophenylacetic acid by using a sodium hydroxide solution under the catalysis of a catalyst to generate sodium 2-hydroxyphenylacetate, adding hydrochloric acid to acidify the above obtained reaction solution, cooling for crystallizing the above obtained acidification product, filtering obtained crystals to obtain sodium chloride-containing 2-hydroxyphenylacetic acid, and carrying out a lactonization reaction in a water carrying agent under the catalysis of iron sulfate to generate benzofuran-2(3H)-one. The method has the advantages of simplicity, easiness in implementation, good economic property, high yield, realization of operation simplification, 2-hydroxyphenylacetic acid loss avoiding and yield increase due to omission of the 2-hydroxyphenylacetic acid purifying process by carrying out the lactonization reaction on sodium chloride-containing crude 2-hydroxyphenylacetic acid directly used as a raw material, and realization of small corrosion to a reaction device, difficult in product carbonization, small catalysis use amount, no complex post-treatment, production cost saving and reduction of generation of three wastes due to iron sulfate being a neutral substance.
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Paragraph 0021
(2017/05/25)
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- Compounding method for azoxystrobin
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The invention discloses a compounding method for azoxystrobin. The method comprises the following steps: compounding 3-(-methoxy)-methanoisobenzofuran-2(3-hydrogen-)-hydrogen; compounding 3-((alpha)-2-(2-(6-chloropyrimidine-4-oxygen) phenyl)-3-methyl methoxyacrylate; compounding (E)-2-(2-(6-chloropyrimidine-4-oxygen) phenyl)-3-methyl methoxyacrylate; and compounding azoxystrobin. The compounding method for azoxystrobin, provided by the invention, is characterized by simple operation steps, mild reaction conditions, low operation difficulty, low energy consumption, environment-friendly compounding process, less wastewater and waste emission, easiness in treatment, high yield of obtained azoxystrobin, reusable reagent, reduction of reagent consumption, low compounding cost, capability of realizing clean production and being worthy of popularization.
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Paragraph 0013
(2017/10/22)
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- Synthesis process of azoxystrobin intermediate compound benzofuranone
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The invention discloses a synthesis process of an azoxystrobin intermediate compound benzofuranone. The synthesis process comprises the following steps: 1) putting a raw material o-chlorophenylacetic acid into a synthesis kettle, adding a catalyst and liquid caustic soda into the synthesis kettle, and performing heating; 2) after the reaction in the synthesis kettle is completed, cooling the synthesis kettle; 3) filtering the material in the synthesis kettle cooled to room temperature, and recovering the catalyst through filtration; 4) transferring the filtrate into a cyclization kettle, inputting a catalyst and toluene, performing heating, and performing a reflux reaction; 5) adding water into the material after the reflux is completed, washing impurities therein, transferring the organic phase into a concentration kettle, and performing concentration; and 6) after the concentration is completed, obtaining a quantitative amount of toluene which is a benzofuranone toluene solution. The production process disclosed by the invention is relatively simple to operate and more friendly to the environment.
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Paragraph 0031; 0032; 0033; 0034; 0035; 0036; 0037-0044
(2018/03/24)
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- Nucleo-Palladation-Triggering Alkene Functionalization: A Route to γ-Lactones
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An unprecedented strategy for the highly effective synthesis of γ-lactones from homoallylic alcohols was achieved by palladium catalysis in one step. The protocol affords aryl, alkyl, and spiro γ-lactones directly from readily available homoallylic alcohols in good yields with excellent functional group tolerance and high chemoselectivity under mild conditions.
- Zheng, Meifang,Chen, Pengquan,Huang, Liangbin,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 5756 - 5759
(2017/11/10)
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- Synthesis of Oxindoles and Benzofuranones via Oxidation of 2-Heterocyclic BMIDAs
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The synthesis of functionalized oxindoles and benzofuranones via oxidation of 2-BMIDA indoles and benzofurans, respectively, is described. Interconversion of boron species (BMIDA→BF3K) was necessary to enable oxidation and overcome boronic acid stability issues associated with a difficult BMIDA hydrolysis. Overall, a robust process was developed that allowed access to a small library of oxindole and benzofuranone products and facilitated the step-efficient synthesis of biologically active compounds containing the oxindole pharmaco-phore.
- Seath, Ciaran P.,Fyfe, James W. B.,Molloy, John J.,Watson, Allan J. B.
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p. 891 - 898
(2017/02/15)
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- One for Many: A Universal Reagent for Acylation Processes
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This work describes acylation reactions facilitated by a type of heterocycle-based acyl transfer agent, 2-acyloxypyridazinone. Reactions of 2-acyloxypyridazinone with carboxylic acids yield mixed carbonic anhydride intermediates, which are reactive and could be coupled with a wide range of substrates including acids, amines, alcohols, and thiols. The wide substrate scope, ease of operation (no additive or catalyst), storage and handling stability, and atom-efficiency from recycling the heterocycle carrier make the reported acylating agent attractive for acylation-based coupling reactions.
- Moon, Hyun Kyung,Sung, Gi Hyeon,Kim, Bo Ram,Park, Jong Keun,Yoon, Yong-Jin,Yoon, Hyo Jae
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supporting information
p. 1725 - 1730
(2016/06/09)
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- Synthesis of 2-BMIDA 6,5-bicyclic heterocycles by Cu(i)/Pd(0)/Cu(II) cascade catalysis of 2-iodoaniline/phenols
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A one-pot cascade reaction for the synthesis of 2-BMIDA 6,5-bicyclic heterocycles has been developed using Cu(i)/Pd(0)/Cu(ii) catalysis. 2-Iodoanilines and phenols undergo a Cu(i)/Pd(0)-catalyzed Sonogashira reaction with ethynyl BMIDA followed by in situ Cu(ii)-catalyzed 5-endo-dig cyclization to generate heterocyclic scaffolds with a BMIDA functional group in the 2-position. The method provides efficient access to borylated indoles, benzofurans, and aza-derivatives, which can be difficult to access through alternative methods.
- Seath, Ciaran P.,Wilson, Kirsty L.,Campbell, Angus,Mowat, Jenna M.,Watson, Allan J.B.
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supporting information
p. 8703 - 8706
(2016/07/15)
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- Unusual hydroxyl effect on fulvene endoperoxide decompositions
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The thermal decomposition of fulvene endoperoxides ordinarily proceeds via an allene oxide intermediate affording oxepin-2(3H)-one derivatives. We have now uncovered new, unusual pathways in these decompositions where the presence of a hydroxyl group on the alkyl or aryl attached to the fulvene exocyclic double bond has a profound effect on the fate of the reactive intermediates derived from the unstable endoperoxides. Computational work supports the proposed mechanistic pathways.
- Erden, Ihsan,Basada, John,Poli, Daniela,Cabrera, Gabriel,Xu, Fupei,Gronert, Scott
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p. 2190 - 2193
(2016/05/02)
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- A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
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A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Nguyen, Thanh V.,Lyons, Demelza J.M.
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supporting information
p. 3131 - 3134
(2015/06/17)
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- Recent developments in the chemistry of heteroaromatic N -oxides
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Selected developments in the chemistry of heteroaromatic N-oxides since 2001 are presented in this review. The use of these N-oxides, both in late-transition-metal-catalyzed oxidations of carbon-carbon triple bonds and in regioselective C-H functionalizations of the heteroarene, are contemporary topics of interest and the focus of the discussion. 1 Introduction 2 Synthesis of Heteroaromatic N-Oxides 2.1 Direct Oxidation of Hindered Heteroarenes 2.2 Through Construction of Heteroaromatic Rings 3 Heteroaromatic N-Oxides as Oxidants 3.1 Alkyne Oxidation 3.2 Allene Oxidation 3.3 Carbene Oxidation 4 Heteroaromatic N-Oxides as Substrates 4.1 Deoxygenative ortho-C-H Functionalization with Prior Activation 4.2 Deoxygenative ortho-C-H Functionalization with Nonstabilized Carbanions 4.3 Nondeoxygenative C-H Functionalization 4.3.1 ortho-C-H Functionalization 4.3.2 N-Oxide Directed ortho-Alkyl C-H Functionalization 4.3.3 N-Oxide Directed Remote C-H Functionalization 4.4 1,3-Dipolar Cycloaddition 5 Conclusion and Outlook.
- Wang, Youliang,Zhang, Liming
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- Developing the scope of o→c aryl migrations: Exploring amide substrates as potential precursors for asymmetric reactions
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A new and mild method for the production of diasteromerically enriched α-aryl carbonyl compounds has been achieved. Although only modest diastereoselectivies are observed, they demonstrate the potential of the method for further optimisation. It also appears that reactions that proceed through a five-membered spirocyclic transition state rearrange, whereas those proceeding through a six-membered transition state do not, but stop at the diaryl ether stage.
- Ameen, Dana,Snape, Timothy J.
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p. 1925 - 1934
(2014/04/03)
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- Developing the Scope of O→C Aryl Migrations: Exploring Amide Substrates as Potential Precursors for Asymmetric Reactions
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A new and mild method for the production of diasteromerically enriched α-aryl carbonyl compounds has been achieved. Although only modest diastereoselectivies are observed, they demonstrate the potential of the method for further optimisation. It also appears that reactions that proceed through a five-membered spirocyclic transition state rearrange, whereas those proceeding through a six-membered transition state do not, but stop at the diaryl ether stage. A mild O→C aryl migration (Truce-Smiles rearrangement reaction) has been expanded to include amides as precursors, and it has been shown that the product ratios are dependent on the structure of the starting amides. Chiral auxiliaries have been incorporated in attempts to make the rearrangement asymmetric and modest diastereoselectivities were obtained.
- Ameen, Dana,Snape, Timothy J.
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p. 1925 - 1934
(2015/10/05)
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- Metal-free oxidative cyclization of alkynyl aryl ethers to benzofuranones
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Readily available phenols can be converted into substituted aryl alkynyl ethers, which react with an N-oxide as an oxidant and catalytic amounts of a Bronsted acid to provide benzofuranones. If non-terminal alkynyl ethers are applied, a 1,2-hydride shift takes place and phenyl acrylates are obtained. Thus activated alkynes can serve as α-oxy carbene precursors even in the absence of a metal catalyst. Copyright
- Graf, Katharina,Ruehl, Carmen L.,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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p. 12727 - 12731
(2013/12/04)
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- METHOD FOR MANUFACTURING ESTER
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The present invention relates to a method for manufacturing an ester from a ketone or an aldehyde, which is a reactive substrate, by a Baeyer-Villiger oxidation reaction using hydrogen peroxide, and in this method, as a catalyst, M(BAr4)n, which is a metal borate, is used (M represents an alkali metal or an alkaline earth metal; Ar represents an aryl; and n is the same number as the valence of M). For example, when cyclohexanone was used as the reactive substrate, and Sr[B(3,5-CF3C6H3)4]2 was used as the catalyst, ε-caprolactone was obtained at an isolated yield of 82%.
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Paragraph 0070; 0075; 0098; 0099
(2013/08/28)
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- Highly efficient and stable Au/Mn2O3 catalyst for oxidative cyclization of 1,4-butanediol to γ-butyrolactone
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In this work, gold nanoparticles deposited on manganese sesquioxide (Mn2O3) showed high activity in the oxidative lactonization of 1,4-butanediol to γ-butyrolactone with air as the oxidant. On the contrary, nano-sized gold supported on manganese dioxide (MnO2) and manganese oxide (MnO) presented much lower activities. XRD, TEM and XPS characterizations revealed that the superior catalytic performance of Au/Mn2O3 could be ascribed to the highest dispersion of gold particles and unique intrinsic properties of Mn 2O3, which possesses the appropriate point of zero charge for deposition-precipitation method, the most quantity of oxygen vacancies and the appropriate gold-support interaction. Au/Mn2O3 exhibited selectivity of 100%, which could facilitate the purification of target product from the reaction mixture. Furthermore, the as-prepared Au/Mn 2O3 catalyst could be recovered by simple filtration, and used repetitively or preserved for a long period without apparent loss of activity.
- Li, Xian,Cui, Yuanyuan,Yang, Xinli,Dai, Wei-Lin,Fan, Kangnian
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- Mild and rapid hydroxylation of aryl/heteroaryl boronic acids and boronate esters with N-oxides
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Aryl and heteroaryl boronic acids and boronate esters are rapidly, often within minutes, transformed into the corresponding phenols by N-oxides in an open flask at ambient temperature. This transformation has broad compatibility with a variety of functional groups.
- Zhu, Chen,Wang, Rui,Falck
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supporting information; experimental part
p. 3494 - 3497
(2012/08/28)
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- Electron-rich PNP-and PNN-type ruthenium(ii) hydrido borohydride pincer complexes. synthesis, structure, and catalytic dehydrogenation of alcohols and hydrogenation of esters
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Electron-rich PNP-and PNN-type ruthenium(II) hydrido borohydride pincer complexes, [RuH(BH4)(tBu-PNP)] (tBu-PNP = (2,6-bis(di-tert-butylphosphinomethyl)pyridine) (5) and [RuH(BH 4)(tBu-PNN)] (tBu-PNN = 2-di-tert- butylphosphinomethyl-6-diethylaminomethylpyridine) (6), were prepared from their corresponding N2-bridged dinuclear Ru(II) complexes [(tBu-PNP) RuCl2]2(μ-N2) (3) and [(tBu-PNN) RuCl2]2(μ-N2) (4), respectively. The X-ray structure of 5 reveals a BH4 -anion η2 coordinated to ruthenium through two bridging hydrides. A variable-temperature 1H NMR study of 6 exhibits interesting fluxional behavior of the BH4 -ligand. Similarly, the Ru(II) hydrido borohydride complex 9, in which the BH4 -moiety is coordinated in a η1 bonding mode, was obtained by reaction of [RuCl 2(PPh3)(iPr-PNP)] (iPr-PNP = 2,6-bis(diisopropylphosphinomethyl)pyridine) (8) with two equivalents of NaBH4 at room temperature. The hydrido borohydride pincer complexes 5, 6, and 9 catalyze the acceptorless dehydrogenative coupling of primary alcohols to esters and the dehydrogenation of secondary alcohols to the corresponding ketones, accompanied by evolution of hydrogen gas. The reactivity follows the order 6 > 9 > 5. With the hydrido borohydride complex 6 as catalyst, high yields (up to 98%) and high turnover numbers (TON~1000) were obtained in the dehydrogenation of primary alcohols under mild and neutral conditions. In addition, 6 effectively catalyzes the hydrogenation of nonactivated aromatic and aliphatic esters to the corresponding alcohols with TON ~200 under a relatively mild pressure of dihydrogen and neutral and homogeneous conditions. Thus, an efficient homogeneous catalytic system for the dehydrogenation- hydrogenation reactions of alcohols is developed, which is relevant to the current interest in hydrogen storage.
- Zhang, Jing,Balaraman, Ekambaram,Leitus, Gregory,Milstein, David
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experimental part
p. 5716 - 5724
(2012/01/14)
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- Oxidation of organotrifluoroborates via oxone
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A method for the oxidation of organotrifluoroborates using Oxone was developed. A variety of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates were converted into the corresponding oxidized products in excellent yields. This method proved to be tolerant of a broad range of functional groups, and in secondary alkyl substrates it was demonstrated to be completely stereospecific.
- Molander, Gary A.,Cavalcanti, Livia N.
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experimental part
p. 623 - 630
(2011/03/20)
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- Enzymatic Baeyer-Villiger oxidation of Benzo-Fused ketones: Formation of regiocomplementary lactones
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Baeyer-Villiger monooxygenases (BVMOs) are enzymes that are known to catalyse the Baeyer-Villiger oxidation of ketones in aqueous media using O2 as oxidant. Herein, we describe the oxidation of a set of diverse benzo-fused ketones by three different BVMOs
- Rioz-Martinez, Ana,De Gonzalo,Torres Pazmino, Daniel E.,Fraaije, Marco W.,Gotor, Vicente
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experimental part
p. 2526 - 2532
(2009/09/25)
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- Tandem catalysis: Direct catalytic synthesis of imines from alcohols using manganese octahedral molecular sieves
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Tandem processes involving catalysts can offer unique and powerful strategies for converting simple starting materials into more complex products in a single reaction vessel. Imines were synthesized directly from alcohols via a tandem catalytic process using manganese octahedral molecular sieves (OMS-2) as catalyst. The synthesis proceeds through two steps: an oxidation of the alcohols to carbonyls followed by the nucleophilic attack by an amine on the carbonyl to form the imine. OMS-2 acts as a bifunctional catalyst and catalyzes two mechanistically distinct processes in a single reaction vessel under the same conditions. Conversions up to 100% were obtained for benzylic alcohols with this efficient, environmentally friendly catalytic reaction. The advantages of this process are that the intermediates need not be isolated and the catalysts can be reused upon simple filtration without loss of activity.
- Sithambaram, Shanthakumar,Kumar, Ranjit,Son, Young-Chan,Suib, Steven L.
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p. 269 - 277
(2008/09/17)
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- Dichlororuthenium(IV) complex of meso-Tetrakis(2,6-dichlorophenyl) porphyrin: Active and robust catalyst for highly selective oxidation of arenes, Unsaturated steroids, and electron-deficient alkenes by using 2,6-dichloropyridine N-oxide
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[RuIV(2,6-Cl2tpp)Cl2], prepared in 90% yield from the reaction of [RuVI(2,6-Cl2tpp)O2] with Me3SiCl and structurally characterized by X-ray crystallography, is markedly superior to [RuIv(tmp)Cl2], [RuIV(ttp)Cl2], and [RuII(por)(CO)] (por = 2,6-Cl2tpp, F20-tpp, F28-tpp) as a catalyst for alkene epoxidation with 2,6-Cl2pyNO (2,6Cl2tpp = meso-tetrakis(2,6-dichlorophenyl)porphyrinato dianion; tmp = meso-tetramesitylporphyrinato dianion; ttp = meso-tetrakis(p-tolyl)porphyrinato dianion; F20-tpp = meso-tetrakis(pentafluorophenyl)porphyrinato dianion; F28-tpp = 2,3,7,8,12,13,17,18-octafluoro-5,10,15,20- tetrakis(pentafluorophenyl)-porphyrinato dianion). The "[Ru IV(2,6-Cl2tpp)Cl2] + 2,6-Cl 2pyNO" protocol oxidized, under acid-free conditions, a wide variety of hydrocarbons including 1) cycloalkenes, conjugated enynes, electron-deficient alkenes (to afford epoxides), 2) arenes (to afford quinones), and 3) Δ5-unsaturated steroids, Δ4-3- ketosteroids, and estratetraene derivatives (to afford epoxide/ketone derivatives of steroids) in up to 99% product yield within several hours with up to 100% substrate conversion and excellent regio- or diastereoselectivity. Catalyst [RuIv(2,6-Cl2tpp)Cl2] is remarkably active and robust toward the above oxidation reactions, and turnover numbers of up to 6.4 × 103, 2.0 × 104, and 1.6 × 104 were obtained for the oxidation of α,β-unsaturated ketones, arenes, and Δ5-unsaturated steroids, respectively.
- Zhang, Jun-Long,Che, Chi-Ming
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p. 3899 - 3914
(2007/10/03)
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- Process for the preparation of lactones and aromatic hydroxycarboxylic acids
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Verfahren zur Herstellung von gegebenenfalls substituierten Hydroxyphenylessigs?uren der Formel in der n 0, 1 2 oder 3 sein kann, R H oder einen C1-C6-Alkylrest, C1-C6-Alkoxyrest, Phenyl, Phenoxy, CN, NO2, SO3H, NH2, F, Cl, I oder Br oder einen 5- oder 6-gliedrigen Ring mit einem N-Atom, der an den Phenylring anelliert ist bedeutet und die Reste X und Y OH, H, ein C1-C6-Alkylrest, ein C1-C6-Alkoxyrest, Phenyl, Phenoxy, CN, NO2, SO3H, NH2, F, Cl, I oder Br sein k?nnen, wobei mindestens einer der Reste X oder Y OH bedeutet oder von gegebenenfalls substituierten Lactonen der Formel bei welchem ein Allylphenol der Formel in Wasser, einem C1-C6-Alkohol oder einem Wasser/Alkoholgemisch mit Ozon korrespondierenden Aldehyd umgesetzt wird, der durch Erw?rmen mit den bei der Ozonolyse entstehenden Peroxiden zur entsprechenden Hydroxyphenylessigs?ure der Formel (I) aufoxidiert wird, die gegebenenfalls, für den Fall, dass X gleich OH ist, zum Lacton der Formel (II) cyclisiert werden kann.
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- Increased enantioselectivity in the addition of diethylzinc to benzaldehyde by the use of chiral ligands containing the α-phenylethylamino group in combination with achiral ligands
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Chiral ligands (S,S)-1, (S,S)-2, (S,S)-3, (S)-4, (S)-5, (S,S)-6, (S,S)-7, and (S,S)-8 turned out to be effective promoters in the enantioselective addition of diethylzinc to benzaldehyde. Interestingly, diamine (S,S)-3 and amino alcohols (S)-5 and (S,S)-7 induce the preferential formation of carbinol (R)-10 (unlike stereoinduction) whereas amido analogues (S,S)-2, (S)-4, and (S,S)-6 favor (S)-10 (like stereoinduction). Molecular modeling at the semiempirical PM3 level provided a reasonable interpretation based on conformational effects in the corresponding transition structures. Combinations of chiral ligands 1-8 with an achiral, flexible ligand (9) gave rise to an activated catalytic system that resulted in faster and higher yielding reactions. Furthermore, substantial increases in the observed enantiomeric excesses of product 10 confirmed the relevant role of achiral bis-(sulfonamide) 9 as activator and "chiral environment amplifier".
- Munoz-Muniz, Omar,Juaristi, Eusebio
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p. 3781 - 3785
(2007/10/03)
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- Enantioselective alkylation and protonation of prochiral enolates in the asymmetric synthesis of β-amino acids
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Achiral 1-benzoyl-3-methylperhydropyrimidin-4-one (1) was deemed a useful, potential precursor for the enantioselective synthesis of α-substituted β-amino acids. Pyrimidinone 1 was prepared from inexpensive β-aminopropanoic acid in 62% overall yield. Prochiral enolate derivative 1 -Li was alkylated in good yield and moderate enantioselectivity in the presence of chiral amines (S)-8, (S,S)-9, (S,S)-10, or (-)-sparteine. The enantioselectivity of the alkylation process is highest in toluene as the solvent and in the presence of lithium bromide as additive. The racemic alkylated derivatives 2 and 3 were readily metallated with LDA to give prochiral enolates 2-Li and 3-Li, that were reprotonated with novel chiral phenolic acids (S)-11, (S,S)-12, (S)-13, and (S,S)-14 in moderate enantioselectivity in the case of 2-Li and good enantioselectivity in the case of 3-Li. The acid (6N HCl) hydrolysis of enantioenriched 2 and 3 proceeded in good yield and without racemization to afford α-alkyl-β-amino acids 4 and 5, respectively.
- Mu?oz-Mu?iz, Omar,Juaristi, Eusebio
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p. 4223 - 4229
(2007/10/03)
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- Substituted cyclic compounds, preparation method and pharmaceutical compositions containing them
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The invention concerns compounds of formula (I): R—A—R′ wherein: A is as defined in the description; R represents a group (V), (VI), (VII) or (VIII), where E, Q, R1, R2, R3, v and R4are as defined in the description; R′ represents a —(CH2)t—R5group wherein t and R5are as defined in the description
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- New synthetic methods: Part I - Regioselective 1, 2-transposition of carbonyl group in carbocyclic and heterocyclic ketones
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A convenient and simple synthetic method for 1, 2- transposition of keto group in pyrazol-5-ones, indan-1,3-dione and benzofuran-3-one is described.
- Chande, Madhukar S.,Amle, Anand P.
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p. 2625 - 2627
(2007/10/03)
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- Designing a non-volatile imaging switch for mass-persistent, chemically amplified photolithography: A model study
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An acid catalysed rearrangement that transforms a bicyclic lactone into a phenolic carboxylic acid has been tested for potential use in chemically amplified microlithographic imaging.
- Klopp, John M.,Bensel, Nicolas,Fresco, Zachary M.,Frechet, Jean M. J.
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p. 2956 - 2957
(2007/10/03)
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- Intramolecular acylation of aryl- and aroyl-aliphatic acids by the action of pyrophosphoryl chloride and phosphorus oxychloride
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Both pyrophosphoryl chloride and phosphorus oxychloride react with aryl aliphatic acids to form mixed anhydrides which undergo intramolecular acylation to afford cyclic ketones without the addition of a Friedel-Crafts catalyst. Aryl and aroyl-benzoic acids could be cyclized to the corresponding anthrones and anthraquinones respectively.
- El-Sayrafi, Sami,Rayyan, Saleh
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p. 279 - 286
(2007/10/03)
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- Lactone-derived carbon-centered radicals: Formation and reactivity with oxygen
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matrix presented Several lactones were examined to test the reactivity of carbon-centered radicals toward oxygen. Notably, the radical derived from 2-coumaranone (4) is unreactive toward oxygen, while 2-cuomaranone itself shows enhanced reactivity toward hydrogen abstraction by alkoxyl radicals. We propose that five parameters influence diminished reactivity toward oxygen, i.e., (a) benzylic resonance stabilization, (b) unpaired spin delocalization on oxygen, (c) favorable stereoelectronic effects, (d) electron-withdrawing effects, and (e) steric effects.
- Bejan, Elena V.,Font-Sanchis, Enrique,Scaiano
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p. 4059 - 4062
(2007/10/03)
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