- Atom efficient Friedel-Crafts acylation of toluene with propionic anhydride over solid mesoporous superacid UDCaT-5
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Friedel-Crafts acylation is ubiquitous in industry and is typically carried out by using more than stoichiometric quantities of homogeneous catalysts. This creates pollution. In this work, acylation of toluene was studied in liquid phase with propionic anhydride with a variety of solid superacids to produce 4′-methylpropiophenone (4′-MPP). The solid superacids were modified versions of zirconia, namely, UDCaT-4, UDCaT-5 and UDCaT-6 developed in our laboratory; amongst which UDCaT-5 was the most active, selective and robust catalyst. The effects of various reaction parameters on the rate of reaction and selectivity were investigated to deduce the intrinsic kinetics of the reaction. The reaction is free from any external mass transfer as well as intraparticle diffusion limitations and is intrinsically kinetically controlled. The acylation conditions were: temperature 180 °C, toluene to propionic anhydride molar ratio 5:1, catalyst loading 0.06 g cm-3, speed of agitation 1000 rpm, under autogenous pressure in a stainless steel autoclave reactor. Propionic acid generated in situ also reacts sequentially with toluene to give 4′-MPP. A conversion of 62% of priopionic anyhydride is obtained after 3 h, with 100% mono-acylated product containing 67% 4′-MPP. Water is the only co-product of the overall reaction. A suitable kinetic model was developed. The reactions were carried out without using any solvent in order to make the process cleaner and greener.
- Yadav, Ganapati D.,Kamble, Shashikant B.
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- KOtBu/DMSO Catalytic System for Isomerization of Allylic Alcohols to Ketones
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The isomerization of allylic alcohols is an important reaction because it can afford carbonyl compounds in an atom-economical manner. Although base-catalyzed methods are more desirable than those using transition-metal catalysts from both the economic and environmental points of view, these methods have several drawbacks, such as narrow substrate scope and high catalyst loading. This paper reports the development of an efficient KOtBu/DMSO catalytic system suitable for the isomerization of a broad range of allylic alcohols with good yields, to which previously reported systems could not be applied. This catalytic system was successfully applied to a tandem allylic isomerization/electrophilic trapping reaction, thereby highlighting its synthetic utility.
- Sai, Masahiro
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supporting information
(2022/04/03)
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- Photoredox/nickel-catalyzed hydroacylation of ethylene with aromatic acids
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We report a general, practical and scalable hydroacylation reaction of ethylene with aromatic carboxylic acids with the synergistic combination of nickel and photoredox catalysis. Under ambient temperature and pressure, feedstock chemicals such as ethylene can be converted into high-value-added aromatic ketones in moderate to good yields (up to 92%) with reaction time of 2-6 hours.
- Chen, Shuai,He, Hengchi,Li, Weipeng,Xie, Jin,Zhang, Lili,Zhu, Chengjian
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supporting information
p. 9064 - 9067
(2021/09/15)
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- Combination of organocatalytic oxidation of alcohols and organolithium chemistry (RLi) in aqueous media, at room temperature and under aerobic conditions
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A tandem protocol to access tertiary alcohols has been developed which combines the organocatalytic oxidation of secondary alcohols to ketones followed by their chemoselective addition by several RLi reagents. Reactions take place at room temperature, under air and in aqueous solutions, a trio of conditions that are typically forbidden in polar organometallic chemistry.
- Elorriaga, David,García-álvarez, Joaquín,González-Sabín, Javier,Hevia, Eva,Morís, Francisco,Presa Soto, Alejandro,Ríos-Lombardía, Nicolás,Rodríguez-álvarez, María Jesús
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supporting information
p. 8932 - 8935
(2020/08/17)
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- Palladium-catalyzed room temperature acylative cross-coupling of activated amides with trialkylboranes
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A highly efficient acylative cross-coupling of trialkylboranes with activated amides has been effected at room temperature to give the corresponding alkyl ketones in good to excellent yields by using 1,3-bis(2,6-diisopropyl)phenylimidazolylidene and 3-chloropyridine co-supported palladium chloride, the PEPPSI catalyst, in the presence of K2CO3 in methyl tert-butyl ether. The scope and limitations of the protocol were investigated, showing good tolerance of acyl, cyano, and ester functional groups in the amide counterpart while halo group competed via the classical Suzuki coupling. The trialkylboranes generated in situ by hydroboration of olefins with BH3 or 9-BBN performed similarly to those separately prepared, making this protocol more practical.
- Shi, Weijia,Zou, Gang
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- Chloramine-T-mediated oxidation of benzylic alcohols using indium(III) triflate
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The efficient oxidation of benzylic alcohols to carbonyl compounds was performed using chloramine-T and a catalytic amount of indium(III) triflate. The primary benzylic alcohols were converted to the corresponding aldehydes in a good yield, and the secondary benzylic alcohols were oxidized to ketones in a high yield. The optimized reaction conditions required 0.3eq of indium(III) triflate and the use of acetonitrile as a solvent.
- Nakahara, Kazuhide,Kitazawa, Chie,Mineno, Tomoko
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p. 801 - 804
(2017/08/09)
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- Enantioselective Hydrogen Atom Transfer: Discovery of Catalytic Promiscuity in Flavin-Dependent 'Ene'-Reductases
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Flavin has long been known to function as a single electron reductant in biological settings, but this reactivity has rarely been observed with flavoproteins used in organic synthesis. Here we describe the discovery of an enantioselective radical dehalogenation pathway for α-bromoesters using flavin-dependent 'ene'-reductases. Mechanistic experiments support the role of flavin hydroquinone as a single electron reductant, flavin semiquinone as the hydrogen atom source, and the enzyme as the source of chirality.
- Sandoval, Braddock A.,Meichan, Andrew J.,Hyster, Todd K.
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p. 11313 - 11316
(2017/08/30)
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- Palladium(II)-catalyzed desulfitative synthesis of aryl ketones from sodium arylsulfinates and nitriles: Scope, limitations, and mechanistic studies
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A fast and efficient protocol for the palladium(II)-catalyzed production of aryl ketones from sodium arylsulfinates and various organic nitriles under controlled microwave irradiation has been developed. The wide scope of the reaction has been demonstrated by combining 14 sodium arylsulfinates and 21 nitriles to give 55 examples of aryl ketones. One additional example illustrated that, through the choice of the nitrile reactant, benzofurans are also accessible. The reaction mechanism was investigated by electrospray ionization mass spectrometry and DFT calculations. The desulfitative synthesis of aryl ketones from nitriles was also compared to the corresponding transformation starting from benzoic acids. Comparison of the energy profiles indicates that the free energy requirement for decarboxylation of 2,6-dimethoxybenzoic acid and especially benzoic acid is higher than the corresponding desulfitative process for generating the key aryl palladium intermediate. The palladium(II) intermediates detected by ESI-MS and the DFT calculations provide a detailed understanding of the catalytic cycle. (Figure Presented).
- Skillinghaug, Bobo,Sk?ld, Christian,Rydfjord, Jonas,Svensson, Fredrik,Behrends, Malte,S?vmarker, Jonas,Sj?berg, Per J. R.,Larhed, Mats
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p. 12018 - 12032
(2015/01/16)
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- Design and synthesis of conformationally constrained analogues of cis-cinnamic acid and evaluation of their plant growth inhibitory activity
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1-O-cis-Cinnamoyl-β-d-glucopyranose is known to be one of the most potent allelochemical candidates and was isolated from Spiraea thunbergii Sieb by Hiradate et al. (2004), who suggested that it derived its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. In this study, key structural features and substituent effects of cis-cinnamic acid (cis-CA) on lettuce root growth inhibition was investigated. These structure-activity relationship studies indicated the importance of the spatial relationship of the aromatic ring and carboxylic acid moieties. In this context, conformationally constrained cis-CA analogues, in which the aromatic ring and cis-olefin were connected by a carbon bridge, were designed, synthesized, and evaluated as plant growth inhibitors. The results of the present study demonstrated that the inhibitory activities of the five-membered and six-membered bridged compounds were enhanced, up to 0.27 μM, and were ten times higher than cis-CA, while the potency of the other compounds was reduced.
- Nishikawa, Keisuke,Fukuda, Hiroshi,Abe, Masato,Nakanishi, Kazunari,Tazawa, Yuta,Yamaguchi, Chihiro,Hiradate, Syuntaro,Fujii, Yoshiharu,Okuda, Katsuhiro,Shindo, Mitsuru
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p. 223 - 234
(2014/01/06)
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- Kinetic resolution of aryl alkenylcarbinols catalyzed by Fc-PIP
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An effective kinetic resolution of a variety of aryl alkenylcarbinols catalyzed by nonenzymatic acyl transfer catalyst Fc-PIP was developed, affording corresponding unreacted alcohols in good to excellent ee value up to 99% and with selectivity factors up to 24.
- Hu, Bin,Meng, Meng,Jiang, Shanshan,Deng, Weiping
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scheme or table
p. 1289 - 1294
(2012/08/28)
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- Chloroindate(III) ionic liquids: Recyclable media for Friedel-Crafts acylation reactions
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Chloroindate(III) ionic liquids are versatile reaction media for Friedel-Crafts acylation reactions; the system is catalytic and totally recyclable, using an aqueous workup, with no leaching of the indium into the product phase. The Royal Society of Chemistry 2005.
- Earle, Martyn J.,Hakala, Ullastiina,Hardacre, Christopher,Karkkainen, Johanna,McAuley, Barry J.,Rooney, David W.,Seddon, Kenneth R.,Thompson, Julian M.,Waehaelae, Kristina
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p. 903 - 905
(2007/10/03)
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- An alkyne hydrosilylation-oxidation strategy for the selective installation of oxygen functionality
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Alkynes bearing propargylic, homopropargylic, and bishomopropargylic hydroxyl groups are shown to serve as precursors for ketone or α-hydroxy ketone functionality. The approach hinges on the intermediacy of vinylsilanes created through regioselective hydrosilylation catalyzed by the complex [Cp*Ru(MeCN)3]-PF6. Several oxidative pathways of linear and cyclic vinylsilanes are studied, and the possibility of diastereoselective epoxidation of cyclic vinylsilanes is demonstrated. The sequences constitute the equivalent of stereoselective aldol, homo-aldol, and bishomo-aldol type processes. The method is applied to a short synthesis of the piperidine alkaloid, spectaline.
- Trost, Barry M.,Ball, Zachary T.,Laemmerhold, Kai M.
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p. 10028 - 10038
(2007/10/03)
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- Photochemical preparation of highly functionalized 1-indanones
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A series of o-alkylphenyl alkyl ketones 1 were synthesized by different methods. The presence of a leaving group X adjacent to the carbonyl group is the special peculiarity of these ketones. Upon irradiation the keto carbonyl group of these compounds undergoes an n-π* excitation followed by a 1,5-hydrogen migration from the o-alkyl substituent to the carbonyl oxygen atom. The thus formed 1,4-diradicals are subject to a very rapid elimination of acid HX, giving 1,5-diradicals. We called this process spin center shift. After intersystem crossing these diradicals cyclize to 1-indanones 20 in good yields. Depending on the solvent and on substituents, o-alkoxyalkyl ketones 22 or benzo-[c]furanes 21 are obtained as byproducts. The mechanism of the cyclization was elucidated by quantum chemical calculations and kinetic measurements.
- Wessig, Pablo,Glombitza, Clemens,Mueller, Gunnar,Teubner, Janek
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p. 7582 - 7591
(2007/10/03)
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- Diminished reactivity of ortho-substituted phenacyl bromides toward nucleophilic displacement
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A systematic increase of substitution rates by tert-butylamine on α-bromopropiophenones is observed with meta or para substituents with increasing electron-withdrawing ability (k x 103 L M-1 min-1 = 12.7 (p-CH3), 15.7 (o-F), 20.5 (H), 20.0 (p-Cl), 23.6 (m-Cl), 27.3 (p-CF3)). Within an ortho-substituted series, the reactivities decrease (k x 103 L M-1 min-1 = 7.64 (o-OCH3), 5.31 (o-CH3), 2.85 (o-Cl), 2.40 (o-CF3)). Ortho-substitution results occur from rotational barrier effects and an Aδσ + Bδσ + repulsion. The major bonding contribution between reaction and α-substituent centers (A-B) is only the σ bond. When π bonding is allowed between A and B (meta/para-substitution), delocalization and stabilization of the reacting center occurs.
- Kalendra, Diane M.,Sickles, Barry R.
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p. 1594 - 1596
(2007/10/03)
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- Friedel-crafts acetylation, propionylation, and butyrylation of toluene catalyzed by solid superacids
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The liquid-solid phase acetylation of toluene with acetic anhydride was carried out over solid superacids of sulfated metal oxides (SO4/MeOx) and supported metal oxides (Me1Ox/Me2Oy) selected from the results in the benzoylation of toluene with benzoic anhydride [K. Arata, H. Nakamura, and M. Shouji, Appl. Catal. A: General, 197, 213 (2000)]. The reaction was conducted by adding dropwise a mixture of 2 mmol of acetic anhydride and 2 mL of toluene onto 0.5 g of catalyst suspended in 13 mL of toluene with stirring at 110 °C in the first period of 30 min, followed by stirring the mixture for 2 h. The yields of 2′-, 3′-, and 4′-methylacetophenones in the distribution of 9-10% 2′-, 1-2% 3′and 89-90% 4′-isomers were 24 and 13% for the sulfated metal oxides of SO4/ZrO2 and SO4/SNO2, those by Pt and Ru promoted sulfated zirconias (Pt-, Ru-SO4/ZrO2) being 21 and 28%, respectively. The supported metal oxides of Fe2O3/ ZrO2 and WO3/ZrO2 gave yields of 18 and 15%, respectively. The propionylation and butyrylation of toluene with propionic and butyric anhydrides were performed over SO4/ZrO2, SO4/SnO2, Pt-SO4/ZrO2, and Ru-SO4/ZrO2; the yields of 7-9% o- and 91-93% p-isomers were 31, 26, 32, and 44% for propionylation and 46, 29, 44, and 55% for butyrylation, respectively. The SO4/ZrO2 catalyst gave a 100% yield of 4′-methoxyacetophenone for the acetylation of anisole with acetic anhydride.
- Nakamura, Hideo,Kashiwara, Yuki,Arata, Kazushi
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p. 1071 - 1074
(2007/10/03)
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- Arylheteroaryl inhibitors of farnesyl-protein transferase
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The present invention is directed to compounds which inhibit famesyl-protein transferase (FTase) and the farnesylation of the oncogene protein Ras. The invention is further directed to chemotherapeutic compositions containing the compounds of this invention and methods for inhibiting famesyl-protein transferase and the famesyl of the oncogene protein Ras.
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- Friedel-Crafts acylation of aromatic hydrocarbons using zeolites
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A convenient heterogeneous catalytic methodology for Friedel-Crafts acylation of benzene and toluene using various aliphatic carboxylic anhydrides over zeolites at 250°C is described. An interesting para selectivity is observed in the case of acylation of toluene over HZSM-5.
- Sreekumar,Padmakumar, Raghavakaimal
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p. 777 - 780
(2007/10/03)
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- Synthesis and activity of 2-methyl-3-aminopropiophenones as centrally acting muscle relaxants
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Some novel 2-methyl-3-aminopropiophenones were synthesized and their centrally acting muscle relaxant activities were,evaluated for an inhibitory effect on the flexor reflex in rats. The structure-activity relationships are discussed. In this series 2-methyl-3-pyrrolidino-1-(4-trifluoromethylphenyl)-propan-1-one (28) showed significant centrally acting muscle relaxant activity. In addition, the activities of each enantiomer (28-(S) and (R)) were studied along with their acute toxicities. Compound 28-(R) was found to exhibit more potent activity and weaker acute toxicity than 28-(S). Accordingly, compound 28-(R) (NK433) is under development as a novel centrally acting muscle relaxant.
- Shiozawa,Narita,Izumi,Kurashige,Sakitama,Ishikawa
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- Steric Effects in the Synthesis of 1,7-Dialkylindans
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Synthesis routes to 1-alkyl(CH3,C2H5,i-C3H7)-6-methylindans and 1-alkyl(CH3,C2H5,i-C3H7)-7-methylindans are described.Members of the latter series, especially 1-isopropyl-7-methylindan, are sterically hindered through a peri interaction.This effect manifests itself throughout the study and necessitated use of alternative synthesis routes.Yields in the Grignard, Peterson olefination, Reformatsky, and Wittig reactions as well as catalytic hydrogenation and Li/NH3 reduction of α,β-unsaturated acids were compared.
- Budhram, Ronald S.,Palaniswamy, Ventakapuran A.,Eisenbraun, Edmund J.
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p. 1402 - 1406
(2007/10/02)
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