- Solid supported Ru(0) nanoparticles: An efficient ligand-free heterogeneous catalyst for aerobic oxidation of benzylic and allylic alcohol to carbonyl
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Polymer immobilized stable, spherical ruthenium nanoparticles were prepared, characterized, and acted as a heterogeneous catalyst for the selective benzylic and allylic alcohol oxidation into the corresponding carbonyls using molecular oxygen. The solid supported Ru(0) (SS-Ru) as a heterogeneous catalyst exhibits good reusability and easy separation from the reaction mixture by filtration.
- Das, Pralay,Aggarwal, Nidhi,Guha, Nitul Ranjan
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Read Online
- Design, synthesis and docking study of pyridine and thieno[2,3-b] pyridine derivatives as anticancer PIM-1 kinase inhibitors
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A series of pyridine and thieno[2,3-b]pyridine derivatives have been designed and synthesized as anticancer PIM-1 kinase inhibitors. Thirty-seven compounds were selected by NCI to be tested initially at a single dose (10 μM) in the full NCI 60 cell line panel. Compound 5b showed potent anticancer activity and was tested twice in the five-dose assay which confirmed its potent antitumor activity (GI50 values 0.302–3.57 μM) against all tested tumor cell lines except six cell lines where they showed moderate sensitivity. This compound was sent to NCI biological evaluation committee and still under consideration for further testing. In addition, the most active anticancer compounds in each series, 5b, 8d, 10c, 13h, and 15e, were evaluated for their PIM-1 kinase inhibitory activity. Compound 8d was the most potent one with IC50 = 0.019 μM followed by 5b, 15e, 10c and 13h with IC50 values 0.044, 0.083, 0.128 and 0.479 μM respectively. Moreover, docking study of the most active compounds in PIM-1 kinase active site was consistent with the in vitro activity.
- Abdelaziz, Marwa E.,El-Miligy, Mostafa M.M.,Fahmy, Salwa M.,Mahran, Mona A.,Hazzaa, Aly A.
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Read Online
- Solid-supported Pd(0): An efficient heterogeneous catalyst for aerobic oxidation of benzyl alcohols into aldehydes and ketones
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Solid-supported nano- and microparticles of Pd(0) (SS-Pd) were used as heterogeneous catalysts for aerobic oxidation of benzyl alcohols. Primary and secondary benzyl alcohols gave the corresponding products in good yields. In addition, the catalysts could be reused up to five runs without significant loss of activities.
- Bandna,Aggarwal, Nidhi,Das, Pralay
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Read Online
- Phytochemistry of Genus Gentiana. XXVI. Identification of a New Di-O-glucosyl Cinnamoyl-C-glucosylflavone in the Leaves of Gentiana X marcailhouana RY.
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A new di-O-glucosyl cinnamoyl-C-glucosylflavone has been identified as 4'-O-β-D-glucosyl-2''-O-isoorientin (1).
- Luong, Minh Duc,Saeby, Jan,Fombasso, Pierre,Jacot-Guillarmod, Andre
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Read Online
- Preparation method of 2, 5-dimethoxyphenylacetic acid
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The invention belongs to the technical field of drug synthesis, and particularly relates to a preparation method of 2, 5-dimethoxyphenylacetic acid, which comprises the following steps: A. Reacting 1,4-dimethoxybenzene with formaldehyde under the action of hydrogen halide, extracting by the reaction system, merging with organic phases, drying, concentrating under reduced pressure, and purifying the crude product to obtain 2-halon methyl-1, 4-dimethoxybenzene ; and B, under the protection of inert gas, putting the 2-halo methyl-1, 4-dimethoxybenzene obtained in the step A, magnesium or butyl lithium and carbon dioxide into a solvent, and then carrying out extraction and deactivation, reduced pressure distillation, extraction, organic phase combination and reduced pressure concentration toobtain the 2, 5-dimethoxyphenylacetic acid. The yield and the total yield of the 2, 5-dimethoxyphenylacetic acid obtained by the method disclosed by the invention are both higher than those of the 2,5-dimethoxyphenylacetic acid synthesized by a Willgerodt-Kindler method.
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Paragraph 0063-0066
(2021/01/29)
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- Preparation method of 2,5-dimethoxyphenylacetic acid
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The invention belongs to the technical field of drug synthesis, and particularly relates to a preparation method of 2,5-dimethoxyphenylacetic acid, wherein the preparation method comprises the following steps: A, reacting 1,4-dimethoxybenzene with formaldehyde under the action of hydrogen halide to obtain 2-halomethyl-1,4-dimethoxybenzene; B, reacting 2-halomethyl-1,4-dimethoxybenzene obtained inthe step A with a cyanation reagent, then diluting, washing, drying and concentrating under reduced pressure, and finally carrying out reduced pressure distillation to obtain 2(2,5-dimethoxyphenyl)acetonitrile; and C, hydrolyzing the 2(2,5-dimethoxyphenyl)acetonitrile obtained in the step B, cooling, extracting, merging, drying, concentrating under reduced pressure and purifying to finally obtainthe 2,5-dimethoxyphenylacetic acid. The yield and the total yield of the 2,5-dimethoxyphenylacetic acid obtained by the method disclosed by the invention are both higher than those of the 2,5-dimethoxyphenylacetic acid synthesized by a Willgerodt-Kindler method, and the yield and the total yield of the 2,5-dimethoxyphenylacetic acid are higher than those of 2,5-dimethoxyphenylacetic acid synthesized by the Willgerodt-Kindler method.
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Paragraph 0071; 0072
(2021/02/06)
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- Preparation method of 2,5-dimethoxyphenylacetic acid
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The invention belongs to the technical field of drug synthesis, and particularly relates to a preparation method of 2,5-dimethoxyphenylacetic acid, wherein the method comprises the following steps: A,reacting 1,4-dimethoxybenzene in a formylation system to obtain 2,5-dimethoxybenzaldehyde; B, reacting the 2,5-dimethoxybenzaldehyde obtained in the step A with a reducing agent, extracting a reaction system, then combining organic phases, drying, concentrating under reduced pressure and distilling a crude product to obtain 2,5-dimethoxybenzyl alcohol; C, reacting the 2,5-dimethoxybenzyl alcoholobtained in the step B with a bromination reagent to obtain 2-bromomethyl-1,4-dimethoxybenzene; and D, reacting the 2-bromomethyl-1,4-dimethoxybenzene obtained in the step C with magnesium or butyl lithium and carbon dioxide in a solvent to obtain the 2,5-dimethoxyphenylacetic acid. The yield and the total yield of the 2,5-dimethoxyphenylacetic acid obtained by the method disclosed by the invention are both higher than those of 2,5-dimethoxyphenylacetic acid synthesized by a Willegerdt-Kindler method.
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Paragraph 0096-0097
(2021/02/06)
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- Hydrogen bond donor solvents enabled metal and halogen-free Friedel–Crafts acylations with virtually no waste stream
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We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.
- Liu, Guangchang,Xu, Bo
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supporting information
p. 869 - 872
(2018/02/09)
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- Hypervalent Iodine as a Terminal Oxidant in Wacker-Type Oxidation of Terminal Olefins to Methyl Ketones
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A mimic of the Wacker process for C=O bond formation in terminal olefins can be initiated by a combination of the Pd(II) and hypervalent iodine reagent, Dess-Martin periodinane to generate methyl ketones. This operationally simple and scalable method offers Markovnikov selectivity, has good functional group compatibility, and is mild and high yielding.
- Chaudhari, Dipali A.,Fernandes, Rodney A.
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p. 2113 - 2121
(2016/03/15)
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- Catalysis of the acylation of aromatic derivatives by metallic tosylates
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A series of metallic tosylates were prepared by ultrasonic metal activation and were further used as efficient catalysts for the acylation of aromatic derivatives.
- Morizur, Vincent,Szafranek, Jessica,Bonhomme, Dominique,Olivero, Sandra,Desmurs, Jean Roger,Du?ach, Elisabet
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supporting information
p. 6813 - 6817
(2015/08/24)
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- Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
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Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
- Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
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p. 129 - 141
(2015/09/28)
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- Synthesis of methyl ketones from terminal olefins using PdCl 2/CrO3 system mimicking the Wacker process
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An efficient synthesis of methyl ketones from terminal olefins using PdCl2/CrO3 system mimicking the Wacker process is developed. The method shows good functional groups compatibility, no aldehyde by-products and is operationally simple. CrO3 is the sole oxidant and replaces both Cu-salts and molecular oxygen, traditionally used in this process. The method holds potential for future applications in organic synthesis.
- Fernandes, Rodney A.,Bethi, Venkati
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p. 4760 - 4767
(2014/06/24)
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- Hypervalent iodine mediated direct one pot transformation of aldehydes to ketones
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An environmentally benign, step economical synthesis of ketones directly from aldehydes has been developed using hypervalent iodine as an oxidant. The key features of this protocol are its mild conditions without the use of any heavy and toxic metals for the synthesis of a wide range of ketones. the Partner Organisations 2014.
- Sagara, Prateep Singh,Chebolu, Rajesh,Bahuguna, Ashish,Ravikumar
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p. 15011 - 15013
(2014/04/17)
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- Attempts directed towards the synthesis of intermediate (aryne)chromium complexes from aryl triflates and from (haloarene)chromium complexes
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The generation of (I·6-aryne)chromium complexes as reactive intermediates was investigated in two ways. Although earlier attempts directed towards triflate eliminations from a variety of tricarbonyl(phenyl triflate)chromium complexes had failed, more electron-rich phenyl triflate complexes were considered. This was accomplished either by substitution with two methoxy groups in the arene ligand or by replacement of one of the three carbonyl ligands of the tricarbonylchromium complex with triphenylphosphane. However, the attempted elimination still did not take place; in spite of the increased electron densities in the aromatic ligands, anionic thia-Fries rearrangements were observed in high yields at -78 °C. As an alternative, elimination of lithium fluoride was tested. Tricarbonyl(2-lithiofluorobenzene) chromium(0) was generated by tin/lithium exchange. After hydrolytic workup, tricarbonyl(fluorobenzene)chromium was obtained as the main product, indicating that the lithiation step had been successful. A dimeric side product provided evidence for the intermediacy of (benzyne)tricarbonylchromium. Copyright
- Werner, Georg,Butenschoen, Holger
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body text
p. 3132 - 3141
(2012/06/30)
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- Polyaniline-supported zinc oxide (ZnO) nanoparticles: An active and stable heterogeneous catalyst for the Friedel-Crafts acylation reaction
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We report herein the synthesis of zinc oxide (ZnO) nanoparticles incorporating a polyaniline (PANI) matrix in aqueous medium and its catalytic performance toward Friedel-Crafts acylation reactions. The acylation reactions demonstrate that polyaniline/ nano-ZnO composites are very active catalysts and are able to activate the reactant at ambient temperature. The obtained nanocatalyst was characterized by Fourier transform-infrared, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller, X-ray diffraction, and particle-size analysis techniques. The catalyst was reusable for five cycles without appreciable loss in activity. Copyright Taylor & Francis Group, LLC.
- Rezaei, Seyed Jamal Tabatabaei,Nabid, Mohammad Reza,Hosseini, Seyedeh Zahra,Abedi, Mahvash
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experimental part
p. 1432 - 1444
(2012/04/17)
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- Friedel-Crafts acylation using bismuth triflate in [BMI][PF6]
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Bismuth trifluoromethanesulfonate was found to be a good catalyst for the Friedel-Crafts acylation. Bismuth triflate immobilized in an ionic liquid was the most efficient catalytic system. Bismuth triflate in [BMI][PF6] catalyzes this reaction under microwave irradiation allowing the rapid synthesis of aryl ketones in excellent yields. The catalyst system was easily recovered and reused several times.
- Tran, Phuong Hoang,Duus, Fritz,Le, Thach Ngoc
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experimental part
p. 222 - 224
(2012/01/30)
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- Dehydrogenation of alcohols under ambient atmosphere by a recyclable sol-gel encaged iridium pincer catalyst
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We demonstrate that a sol-gel entrapped iridium-pincer catalyst 1 is capable of promoting acceptorless dehydrogenation of primary and secondary alcohols. Although the dehydrogenations by the non-heterogenized catalyst are faster than by the sol-gel encaged complex, recyclability and significant stabilization of the organometallic species toward non-inert conditions represent a clear advantage from the environmental and practical points of view.
- Oded, Kobi,Musa, Sanaa,Gelman, Dmitri,Blum, Jochanan
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experimental part
p. 68 - 70
(2012/06/16)
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- Nano-sulfated titania (TiO2/SO2-4) as a new solid acid catalyst for Friedel-Crafts acylation and Beckman rearrangement in solvent-free conditions
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The present work describes a novel application of nano-sulfated titania (nano-ST) as a solid acid catalyst for Friedel-Crafts acylation and Beckmann rearrangement. A nano-ST catalyst has been synthesized and characterized using various techniques such as XRD, scanning electron morphology, transmission electron microscopy, FT-IR, measurement of the specific surface area by Brunauer-Emmett-Teller theory and thermal analysis. The influences of various reaction parameters such as reaction temperature, molar ratio of reactants, reaction time and solvent effects have been investigated. [image omitted].
- Hosseini-Sarvari, Mona,Safary, Ensieh
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experimental part
p. 463 - 473
(2012/06/16)
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- Acylation of aromatic ethers using different carboxylic acid anhydrides as acylating agents in the presence of nontoxic, noncorrosive resin amberlyst 15 as a solid acid catalyst
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Friedel-Crafts acylation of aromatic ethers, anisole, 2-methoxynaphthalene, and dimethoxybenzenes with different acid anhydrides is carried out in the presence of an inexpensive and nonhazardous solid acid, Amberlyst 15. The catalyst is reusable, thus making the process environmentally friendly.
- Pande, Manoj A.,Samant, Shriniwas D.
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experimental part
p. 754 - 761
(2011/04/12)
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- Synthesis of aryl ketones by palladium(II)-catalyzed decarboxylative addition of benzoic acids to nitriles
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An efficient, sustainable method for the preparation of aryl ketones from ortho-substituted benzoic acids proceeds through their decarboxylation to generate an aryl-palladium species, followed by addition to a nitrile and hydrolysis of the intermediate ketimine.
- Lindh, Jonas,Sjoeberg, Per J. R.,Larhed, Mats
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supporting information; experimental part
p. 7733 - 7737
(2011/01/05)
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- Catalytic Friedel-Crafts acylation and benzoylation of aromatic compounds using activated hematite as a novel heterogeneous catalyst
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Catalytic Friedel-Crafts acylation of benzene and unactivated benzenes such as chlorobenzene and nitrobenzene have been successfully carried out using activated hematite (α-Fe2O3) as a new, heterogeneous and green catalyst. Sonication of neat α-Fe2O3 in a water bath under air atmosphere at room temperature followed by heating at 200°C, dramatically increase the activity of α-Fe2O 3. With the catalyst loading as low as 5.0mol%, a wide variety of benzene derivatives were easily converted into the corresponding acylated products in a clean and high-yielding acylation reaction. It was found that the activated α-Fe2O3 could be efficiently recycled and reused several times by simple washing with ethyl acetate, this cannot be attained with most of the traditional catalysts. Copyright
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi,Khalifeh, Reza
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experimental part
p. 3031 - 3044
(2011/02/21)
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- Improved synthesis of diquinones
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Preparation of a series of substituted diquinones is reported. In most examples, inverse order of addition (addition of a dimethoxybenzene derivative to a CAN solution) has been found to produce higher yields of diquinones than the traditional protocol in which the oxidant is added to the arene. Georg Thieme Verlag Stuttgart.
- Love, Brian E.,Bonner-Stewart, Jeffrey,Forrest, Lori A.
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body text
p. 813 - 817
(2009/06/19)
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- Microwave-assisted dehalogenation of α-haloketones by zinc and ammonium chloride in alcohol
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The treatment of α-haloketones with 1.5 equiv. of Zn and 1 equiv. of NH4Cl in ethanol for 0.5αmin gave the corresponding ketones with excellent yields under microwave irradiation. Vic-dibromides and 2,2-dibromoacetophenone can be efficiently debrominated to alkenes and acetophenones, respectively. Copyright Taylor & Francis Group, LLC.
- Li, Jian,Ye, Deju,Liu, Hong,Luo, Xiaoming,Jiang, Hualiang
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p. 567 - 575
(2008/04/12)
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- Transformation of aryl acyloin O-alkyl and O-phenyl derivatives to ketones
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The treatment of aryl acyloin (α-hydroxyketone) O-alkyl and O-phenyl derivatives with 2-3 equiv of Zn and 1-2 equiv of NH4Cl in ethanol, refluxing for 20-120 min, gave the corresponding ketones with excellent yields. Further, α,β-epoxy ketones can be efficiently transformed to β-hydroxy ketones, and 2,2-dialkoxy-1-phenyl ketone also can be dealkoxylated to 1-phenyl ketone. Copyright Taylor & Francis Group, LLC.
- Yao, Zhiyi,Ye, Deju,Liu, Hong,Chen, Kaixian,Jiang, Hualiang
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p. 149 - 156
(2007/10/03)
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- Catalytic Friedel-Crafts acylation of aromatic ethers using Sml3
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10% mol Sml3 catalysed the Friedel-Crafts acylation of aromatic ethers by acyl chlorides in acetonitrile with the yields of 48-82%. Reactions of various substituted aromatic ethers with acyl chloride were studied. The structures of compounds were established by IR and 1H NMR. The main product obtained with anisole is the para-substituted compound with only a trace (3, a pattern repeated with the other aromatic ethers used.
- Chen, Xiaohang,Yu, Mingxin,Wang, Meijun
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- Reaction of chalcones with basic hydrogen peroxide: A structure and reactivity study
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Chalcone epoxides are important intermediates for the synthesis of 3,5-diarylpyrazoles. Twenty different chalcones were oxidized with hydrogen peroxide and potassium carbonate in order to produce the corresponding epoxides. The electronic nature of the substituents on the A- and B-ring of the chalcones significantly affected the reaction outcome: (i) electron donating groups on the A-and B-ring aided the reversion of the chalcones to the corresponding benzaldehydes, (ii) electron withdrawing groups on the B-ring promoted formation of the desired chalcone-epoxides in high chemical yields, and (iii) the presence of electron withdrawing groups (A-ring of the chalcones), regardless of the substituents on the B-ring, produced a mixture of epoxide, unreacted chalcone, benzaldehyde and acetophenone.
- Holt Jr., Herman,LeBlanc, Regan,Dickson, John,Brown, Toni,Maddox, Jessica R.,Lee, Moses
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p. 465 - 470
(2007/10/03)
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- Simple and improved procedure for the regioselective acylation of aromatic ethers with carboxylic acids on the surface of graphite in the presence of methanesulfonic acid
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Friedel-Crafts acylation of aromatic compounds such as anisole has been successfully carried out using the combination of graphite with MeSO 3H. Both aromatic and aliphatic carboxylic acids reacted smoothly under the conditions to afford the corresponding aromatic ketones in high yield.
- Sarvari, Mona Hosseini,Sharghi, Hashem
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p. 2165 - 2168
(2007/10/03)
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- Antimony(V) chloride-benzyltriethylammonium chloride complex as an efficient catalyst for friedel-crafts acylation reactions
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A novel catalytic system, the complex of antimony(V) chloride (SbCl 5) and benzyltriethylammonium chloride (TEBA), C6H 5CH2NEt3(SbCl5)2Cl complex, is described for Friedel-Crafts acylation reactions of aromatics with acyl and sulfonyl chlorides. The catalyst has a number of useful characteristics, such as ready access, minimal toxicity, reusability, insensitivity to atmosphere and moisture, rapid acylation with high yield, and ease of operation.
- Huang, An-Ping,Liu, Xue-Yuan,Li, Lian-Hua,Wu, Xiao-Li,Liu, Wei-Min,Liang, Yong-Min
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p. 599 - 602
(2007/10/03)
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- Reactions on a solid surface. A simple, economical and efficient Friedel-Crafts acylation reaction over zinc oxide (ZnO) as a new catalyst
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Zinc oxide (ZnO) brings about a rapid Friedel-Crafts acylation of a range of activated and unactivated aromatic compounds such as anisole and chlorobenzene with acid chlorides in solvent-free conditions at room temperature. The ZnO powder can be reused up to three times after simple washing with dichloromethane.
- Sarvari, Mona Hosseini,Sharghi, Hashem
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p. 6953 - 6956
(2007/10/03)
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- Synthesis of novel (phenylalkyl)amines for the investigation of structure-activity relationships: Part 3. 4-Ethynyl-2,5-dimethoxyphenethylamine (=4-ethynyl-2,5-dimethoxybenzeneethanamine; 2C-YN)
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An easy and efficient pathway for the preparation of 4-ethynyl-2,5-dimethoxyphenethylamine (=4-ethynyl-2,5-dimethoxybenzeneethanamine; 2C-YN; 1) was developed, an ethynyl analogue of the potent 5-HT2A/C agonists, e.g., 4-iodo-2,5-dimethoxy-amphetamine (DOI; 2b). The ethynyl moiety was introduced by a Pd-catalyzed Sonogashira reaction of (trimethylsilyl)ethyne with N-(trifluoroacetyl)-protected 4-iodo-2,5-dimethoxyphenethylamine (7) in almost quantitative yield within only 1 h. Removal of the Me3Si group was accomplished with Bu4NF. Final N-deprotection by NaOH treatment afforded the novel phenethylamine 1 in an overall yield of 88percent.
- Trachsel, Daniel
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p. 2754 - 2759
(2007/10/03)
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- Acid-mediated specific α,α-diarylation and α-monoarylation reactions of pyruvic acid with/without decarbonylation
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Pyruvic acid (3) was found to be arylated chemoselectively at the α- ketocarbonyl carbon in P2O5-MsOH affording decarbonylative α,α-diarylated products 5, decarbonylative α-monoarylated compounds 6, or non- decarbonylative α,α-diarylated adducts 7 depending on the reactivity of arenes (4a-g), in contrast to Lewis acid-catalyzed reaction of its acid chloride (2).
- Yonezawa, Noriyuki,Hino, Tetsuo,Kinuno, Tsuyoshi,Matsuki, Toshiyuki,Ikeda, Tomiki
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p. 1687 - 1695
(2007/10/03)
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- Rh(I)-catalysed asymmetric hydrosilylation using new oxazoline ligands with potential charge-transfer properties
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Novel N′-methylated 2-(oxazolin-2-yl)-4,4′-bipyridinium salts, bearing a chiral oxazoline moiety, were tested in the Rh(I)-catalysed enantioselective hydrosilylation. After coordination to rhodium these electron-attracting ligands are supposed to exhibit charge-transfer effects with electron-donating substrates. Therefore, a new catalytic hydrosilylation reaction with 2,5-dimethoxyacetophenone as an electron-rich substrate was developed. The results were compared with those of the non-methylated 2-(oxazolin-2-yl)-4,4′-bipyridine and related ligands. In addition, the new ligands and Rh(I)-complexes were tested in the hydrosilylation of acetophenone.
- Brunner, Henri,Stoeriko, Reinhard
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p. 783 - 788
(2007/10/03)
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- Facile transformation of N,N-dimethylhydrazones and tosylhydrazones to ketones with dimethylsulfate and potassium carbonate
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N,N-Dimethylhydrazones and tosylhydrazones can be converted to their ketones in good to excellent yields with dimethylsulfate and K2CO3.
- Kamal, Ahmed,Arifuddin,Rao, N. Venugopal
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p. 3927 - 3931
(2007/10/03)
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- Time-resolved fluorescence and transient spectroscopy in determining photochemical and photophysical channels in reacting systems in solutions and microheterogeneous media
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Characterization of short-lived intermediates in homogeneous and microheterogeneous systems has been carried out using time-resolved spectroscopic techniques. The data obtained from these techniques have been analyzed in a relatively unconventional manner to elucidate complex transient behavior for two reactive systems. The highly nonexponential fluorescence decay for a series of trans-stilbene-derivatized amphiphiles that readily form bilayer systems in aqueous media has been analyzed using a distribution of lifetimes analysis (DLA). The utility of DLA for quantitative studies was first determined by simulation of artificial decay data. Despite some limitations in DLA, qualitative conclusions as to the nature of the fluorescing species may be drawn when supplementary information such as steady-state spectroscopic data are also considered. The results indicate that the observed fluorescence originates from different types of excited- state species that consist of two or more trans-stilbene units; one of the emissions is attributed to the excited state of a ground-state aggregate while the other is assigned to an excimer that may arise from a 'defect' in the bilayer. The nonexponential nature of the decays is attributed to distributions of environments experienced by the fluorescing species. Electron transfer (ET) reactions between several excited pinacols and carbon tetrachloride in solution have been found to yield products with quantum yields that are higher than unity in the presence of oxygen, suggesting a chain mechanism for product formation. In these systems both the donor and the acceptor undergo bond fragmentation following the initial ET step. The individual steps involved in the proposed mechanism fur these systems have been investigated in part using different steady-state and time-resolved laser spectroscopic techniques. However, it was also necessary to utilize pulse radiolysis in order to confirm the involvement of certain radical intermediates that were not observable by the usual flash photolysis techniques.
- Whitten, David G.,Farahat, Mohammad S.,Gaillard, Elizabeth R.
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- Electrogenerated acid catalyzed acylation of electron-rich aromatics
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The acylation of electron-rich aromatic compounds was achieved in good yields under very mild conditions using an electrogenerated acid catalyst. M(ClO4)n dissolved in an organic anhydride (optionally mixed with a polar aprotic solvent) is useful for the electrochemical transformation in a divided cell.
- Gatti, Norberto
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p. 3933 - 3936
(2007/10/02)
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- EFFECT OF STRUCTURE ON PHOTOALCOHOLYSIS OF AROMATIC α-HALOKETONES
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Desyl halide, α-bromophenylacetate, and 2,5-dimethoxy-α-bromoacetophenones undergo smooth photomethanolysis, whereas simple α-bromoacetophenone undergoes photoreduction to give acetophenone.
- Izawa, Yasuji,Watoh, Yasushi,Tomioka, Hideo
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- The Chemistry of Nitrilium Salts. Part 1. Acylation of Phenols and Phenol Ethers with Nitriles and Trifluoromethanesulphonic Acid
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Aliphatic nitriles, RCN (R = Me, n-Pr, CH2Cl, and CCl3), in the presence of trifluoromethanesulphonic acid have been found to react with a number of mono-, di-, and tri-substituted phenols and phenol ethers at room temperature to give ketones after hydrolysis of the reaction mixture.Moderate to good yields of acylation products are obtained in the majority of these reactions.The yield with malononitrile and succinonitrile, which are only slightly soluble in the reaction medium, are generally poor, and reaction involves only one of the available nitrile groups.Attempts to use diethyl ether and dichloromethane as solvents for some of these reactions were unsuccessful, but limited success was achieved with nitromethane.
- Booth, Brian L.,Noori, Ghazi F.M.
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p. 2894 - 2900
(2007/10/02)
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- Synthesis of C-Ring-Functionalized A-Ring-Aromatic Trichothecane Analogues
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15,16-Dinor-4α-acetoxy-8-methoxy-6,8,10-trichothecatriene 12,13-epoxide (11) was prepared from 2α-(2-acetoxy-5-methoxyphenyl)-2β-methyl-3α-acetoxycyclopentanone (8) in three steps (bromination, DBN-induced cyclization, and spiroepoxidation).The cyclopentanone 8 was prepared from the hemiketal 6a which was prepared from 2'-acetoxy-5'-methoxyacetophenone (3f) in a reaction sequence involving the boron trifluoride catalyzed aldol addition of 1,2-bis(trimethylsilyloxy)cyclobutene followed by a trifluoroacetic acid catalyzed pinacol rearrangement of the cyclobutanone intermediate.
- Anderson, Wayne K.,Lee, George E.
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p. 501 - 506
(2007/10/02)
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- Anodic Oxidation of 1,4-Dimethoxy Aromatic Compounds. A Facile Route to Functionalized Quinone Bisketals.
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The anodic oxidation of 12 functionalized 1,4-dimethoxybenzene derivatives and 8 functionalized 1,4-dimethoxynaphthalenes has been studied under a variety of conditions.Many substituted 1,4-dimethoxy aromatics afford high yields of the respective quinone bisketals by single-cell anodic oxidation without accurate control of the electrode potential.Oxidizable groups offen complicate the anodic oxidation; however, in some cases protected derivatives of these functionalities can be converted to the bisketals in good yields.Aromatics containing reducible functions can besmoothly oxidized to quinone bisketals by the use of a divided cell.The current efficiencies and the effect of electrode material on selected systems are reported and discussed.
- Henton, Daniel R.,McCreery, Richard L.,Swenton, John S.
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p. 369 - 378
(2007/10/02)
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- HALOKETONE DEHALOGENATION BY IODIDE ION
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NaI in aqueous acid-THF is an efficient reagent for the dehalogenation of α-haloketones.
- Gemal, A.L.,Luche, J.L.
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p. 3195 - 3198
(2007/10/02)
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- Psychotomimetic phenylisopropylamines. 5. 4 alkyl 2,5 dimethoxyphenylisopropylamines
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A homologous series of 4 alkyl 2,5 dimethoxyphenylisopropylamines (alkyl = H through n C5H11 and t C4H9) was synthesized and compared with mescaline as serotonin agonists in a sheep umbilical preparation. The three carbon homolog 6d was found to be the most potent of the straight chain series in accordance with its observed psychotomimetic effectiveness in man.
- Shulgin,Dyer
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p. 1201 - 1204
(2007/10/06)
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