- Iridium Complexes as Efficient Catalysts for Construction of α-Substituted Ketones via Hydrogen Borrowing of Alcohols in Water
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Ketones are of great importance in synthesis, biology, and pharmaceuticals. This paper reports an iridium complexes-catalyzed cross-coupling of alcohols via hydrogen borrowing, affording a series of α-alkylated ketones in high yield (86 %–95 %) and chemoselectivities (>99 : 1). This methodology has the advantages of low catalyst loading (0.1 mol%) and environmentally benign water as the solvent. Studies have shown the amount of base has a great impact on chemoselectivities. Meanwhile, deuteration experiments show water plays an important role in accelerating the reduction of the unsaturated ketones intermediates. Remarkably, a gram-scale experiment demonstrates this methodology of iridium-catalyzed cross-coupling of alcohols has potential application in the practical synthesis of α-alkylated ketones.
- Luo, Nianhua,Zhong, Yuhong,Wen, Huiling,Shui, Hongling,Luo, Renshi
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p. 1355 - 1364
(2021/03/03)
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- Novel benzene-based carbamates for ache/bche inhibition: Synthesis and ligand/structure-oriented sar study
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A series of new benzene-based derivatives was designed, synthesized and comprehensively characterized. All of the tested compounds were evaluated for their in vitro ability to potentially inhibit the acetyl-and butyrylcholinesterase enzymes. The selectivity index of individual molecules to cholinesterases was also determined. Generally, the inhibitory potency was stronger against butyryl-compared to acetylcholinesterase; however, some of the compounds showed a promising inhibition of both enzymes. In fact, two compounds (23, benzyl ethyl(1-oxo-1-phenylpropan-2-yl)carbamate and 28, benzyl (1-(3-chlorophenyl)-1-oxopropan-2-yl) (methyl)carbamate) had a very high selectivity index, while the second one (28) reached the lowest inhibitory concentration IC50 value, which corresponds quite well with galanthamine. Moreover, comparative receptor-independent and receptor-dependent structure–activity studies were conducted to explain the observed variations in inhibiting the potential of the investigated carbamate series. The principal objective of the ligand-based study was to comparatively analyze the molecular surface to gain insight into the electronic and/or steric factors that govern the ability to inhibit enzyme activities. The spatial distribution of potentially important steric and electrostatic factors was determined using the probability-guided pharmacophore mapping procedure, which is based on the iterative variable elimination method. Additionally, planar and spatial maps of the host–target interactions were created for all of the active compounds and compared with the drug molecules using the docking methodology.
- Bak, Andrzej,Kozik, Violetta,Kozakiewicz, Dariusz,Gajcy, Kamila,Strub, Daniel Jan,Swietlicka, Aleksandra,Stepankova, Sarka,Imramovsky, Ales,Polanski, Jaroslaw,Smolinski, Adam,Jampilek, Josef
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- Solvent free, light induced 1,2-bromine shift reaction of α-bromo ketones
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Photolysis of α-bromopropiophenones in acetonitrile results in formation of β-bromopropiophenones with good product selectivity, which can be coined as 1,2-Br shift reaction. The product selectivity increases when the reaction is done in neat or solid state, where only the 1,2-Br shift product is formed in some cases. The reaction is suggested to proceed by C–Br bond homolysis to give a radical pair, followed by disproportionation and conjugate addition of HBr to the α,β-unsaturated ketone intermediate. When the unsaturated intermediate is stabilized by an extra conjugation, the reaction stops at the stage, in which the unsaturated ketone becomes a major product. The synthetic method described in this research fits in a category of eco-friendly organic synthesis nicely since the reaction does not use volatile organic solvents and any other additives such as acid, base or metal catalysts, etc. Besides, the method fits into perfect atom economy, which does not give any side products. The synthetic method should find much advantage over other alternative methods to obtain β-bromo carbonyl compounds.
- An, Sejin,Moon, Da Yoon,Park, Bong Ser
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p. 6922 - 6928
(2018/10/24)
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- Nickel-Catalyzed Addition of Arylboronic Acids to Alkyl Nitriles for Synthesis of Aryl Ketones in Fluorinated Solvent
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A mild and efficient nickel-catalyzed addition of arylboronic acids to alkyl nitriles in a fluorinated solvent for the synthesis of various aryl ketones is described. A broad range of arylboronic acids and alkyl nitriles were investigated, and the desired products were obtained with good to excellent yields under the optimized conditions. This method provides an opportunity for the synthesis of aryl ketones from alkyl nitriles, especially acetonitrile, with a non-noble metal catalyst in one pot.
- Tu, Dong-Huai,Li, Yang,Zhao, Bo,Gu, Yu-Jie,Wang, Bo,Lu, Ju-You,Lu, Jian
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supporting information
p. 593 - 596
(2017/12/06)
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- Reactions catalyzed by a binuclear copper complex: Selective oxidation of alkenes to carbonyls with O2
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Terminal alkenes were selectively cleaved into ketones and aldehydes catalyzed by a binuclear copper catalyst bearing a simple salicylate ligand with O2 as the oxidant. The reaction was carried out under an atmosphere of O2 (balloon) with 0.5 mol% of catalyst and could be performed on a gram scale, providing a convenient and practical method for the cleavage of terminal alkenes into carbonyl compounds.
- Liu, Yuxia,Xue, Dong,Li, Chaoqun,Xiao, Jianliang,Wang, Chao
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p. 5510 - 5514
(2017/12/08)
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- Method for synthesizing m-chlorophenylacetone
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The invention discloses a method for synthesizing m-chlorophenylacetone. The method comprises the following steps: generating a Grignard reagent from magnesium and bromoethane in a tetrahydrofuran (THF) solution, and performing a reaction on the Grignard reagent and m-chlorobenzonitrile, thereby obtaining m-chlorophenylacetone. The method is simple to operate, advanced in process and easy in industrial production, and a solvent can be recycled. The yield of the m-chlorophenylacetone generated by using the method is up to 92.6%, and the liquid-phase purity of the m-chlorophenylacetone can be up to 99.93% or greater.
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Paragraph 0019; 0024; 0025
(2017/08/29)
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- Transition-Metal-Free Self-Hydrogen-Transferring Allylic Isomerization
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Phenanthroline and tert-butoxide have been established as powerful radical initiators in reactions such as the SRN1-type coupling reactions due to the cooperation of large heteroarenes and a special feature of tert-butoxide. The first phenanthroline-tert-butoxide-catalyzed transition-metal-free allylic isomerization is described. The resulting ketones are key intermediates for indenes. The control experiments rule out the base-promoted allylic anion pathway. The radical pathway is supported by experimental evidence that includes kinetic study, kinetic isotope effect, isotope-labeling experiments, trapping experiments, and EPR experiments.
- Zheng, Hong-Xing,Xiao, Zu-Feng,Yao, Chuan-Zhi,Li, Qiang-Qiang,Ning, Xiao-Shan,Kang, Yan-Biao,Tang, Yong
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supporting information
p. 6102 - 6105
(2016/01/09)
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- A chemoselective α-aminoxylation of aryl ketones: a cross dehydrogenative coupling reaction catalysed by Bu4NI
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Tetrabutyl ammonium iodide (TBAI) catalyzed α-aminoxylation of ketones using aq. TBHP as an oxidant has been accomplished. We have shown that the CDC (cross dehydrogenative coupling) reactions of ketones with N-hydroxyimidates such as N-hydroxysuccinimide (NHSI), N-hydroxyphthalimide (NHPI), N-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) lead to the corresponding oxygenated products in good to moderate yields. The application of this method has been demonstrated by transforming a few coupled products into synthetically useful intermediates and products.
- Siddaraju, Yogesh,Prabhu, Kandikere Ramaiah
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supporting information
p. 11651 - 11656
(2015/12/08)
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- N, N′-dioxide-Cu(OTf)2 complex catalyzed highly enantioselective amination reaction of N-acetyl enamide
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The N,N′-dioxide-Cu(OTf)2 complexes were applied in the asymmetric amination reaction of N-acetyl enamides with dialkyl azodicarboxylate, giving the corresponding products in good yields with high enantioselectivities (up to 91% ee). Precursors of vicinal diamine were readily obtained with excellent diastereoselectivities (>95:5) by NaBH4 reduction.
- Chang, Lu,Kuang, Yulong,Qin, Bo,Zhou, Xin,Liu, Xiaohua,Lin, Lili,Feng, Xiaoming
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supporting information; scheme or table
p. 2214 - 2217
(2010/08/06)
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- First catalytic and green synthesis of aryl-(Z)-vinyl chlorides and its plausible addition-elimination mechanism
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(Chemical Equation Presented) Via a catalytic cycle in the presence of scandium triflate (2 mol %)/DMF (1 mol %)/benzoyl chloride (5 mol %), aromatic ketones were treated with bis(trichloromethyl) carbonate (BTC) to afford aryl-(Z)-vinyl chlorides. All metal triflates tested in the reaction showed highly catalytic activity. A plausible addition-elimination mechanism was proposed. The present work describes the first catalytic and green route to the synthesis of aryl-(Z)-vinyl chlorides.
- Su, Weike,Jin, Can
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p. 993 - 996
(2007/10/03)
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- A practical synthesis of multifunctional ketones through the fukuyama coupling reaction
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A highly efficient, robust and scalable protocol for the synthesis of multifunctional ketones through Fukuyama coupling, i.e., cross-coupling of thiol esters with zinc reagents, has been developed. Treatment of thiol esters with alkylzinc iodides or dialkyl zincs in the presence of palladium on activated carbon (Pd/C) or palladium acetate [Pd(OAc)2] furnished the corresponding ketones in high yields. Evaluation of the properties-activities relationship of the Pd/C-catalyzed reaction has proven that oxidic Pd/C is much more potent than reduced Pd/C in the reaction of thiolactone la with zinc reagent 2a. Based on the dependence of the Pd/C-catalyzed reaction on the nature of Pd/C in combination with the extent of the Pd leaching from Pd/C to the solution, a dual reaction mechanism for the Pd/C-catalyzed Fukuyama coupling reaction, which includes heterogeneous and homogeneous catalytic cycles, was proposed. The marked reduction of the zinc reagents and the use of Pd(OAc) 2 in much smaller amounts were achieved when zinc bromide was added. This supports a hypothesis where a shift of the Schlenk equilibrium from inactive dialkylzincs (R2Zn) to active organozinc species, such as alkylzinc halides (RZnX) and three-coordinate species [(RZnX2) -. (ZnX)+], and generation of the stabilized monomeric Pd complexes during the reaction, may facilitate the reaction.
- Mori, Yoshikazu,Seki, Masahiko
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p. 2027 - 2038
(2008/09/17)
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- A novel procedure for the synthesis of multifunctional ketones through the Fukuyama coupling reaction employing dialkylzincs
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Treatment of thiol esters 1 with dialkylzincs 2 in the presence of zinc bromide, that was in situ prepared from zinc dust and bromine, provided various functionalized ketones 3 in high yields. The reaction mechanism, which may shift the Schlenk equilibrium from dialkylzincs 2 to reactive alkylzinc bromide 5, was postulated to account for the facile coupling reaction.
- Mori, Yoshikazu,Seki, Masahiko
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p. 7343 - 7345
(2007/10/03)
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- Biocatalytically assisted preparation of antifungal chlorophenylpropanols
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Fermenting baker's yeast converts 4′-chloropropiophenone 1 and 3′-chloropropiophenone 2 into enantiopure (S)-(-)-1-(4′-chlorophenyl)propan-1-ol (S)-3 and (S)-(+)-1-(3′-chlorophenyl)propan-1-ol (S)-4, respectively. Application of inhibitors and organic solvents as additives enhanced the enantiomeric excesses. Enantiopure compounds (R)-(+)-1-(4′-chlorophenyl)propan-1-ol ((R)-3) and (R)-(+)-1-(3′-chlorophenyl)propan-1-ol (R)-4 were prepared by lipase-mediated esterifications of the racemic alcohols. Maximum inhibition of the growth of the phytopathogenic fungus Botrytis cinerea was shown for the (R)-enantiomers.
- Bustillo, Antonio J.,Aleu, Josefina,Hernandez-Galan, Rosario,Collado, Isidro G.
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p. 1681 - 1686
(2007/10/03)
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- A novel ketone synthesis by a palladium-catalyzed reaction of thiol esters and organozinc reagents
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A variety of ketones have been prepared by a palladium-catalyzed reaction of ethanethiol esters with organozinc reagents. Various functional groups, including esters, ketones, aromatic halides and aldehydes, tolerate the reaction conditions. The reaction can also be applied to the synthesis of α-amino ketones using the corresponding L-α-amino thiol esters without racemization.
- Tokuyama, Hidetoshi,Yokoshima, Satoshi,Yamashita, Tohru,Fukuyama, Tohru
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p. 3189 - 3192
(2007/10/03)
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- Synthesis and evaluation of the anticonvulsant activity of a series of 2-amino-1-phenyl-1-propranols derived from the metabolites of the antidepressant bupropion
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A series of 2-amino-1-phenyl-1-propanols that are structurally related to known metabolites of bupropion, 1 (Wellbutrin) were synthesized and evaluated as potential anticonvulsants. The (R*,R*)-2-tert-butylamino-1-(3-trifluoromethylphenyl) propanol 20 had an ED50 of 16.5 ± 2.8 mg/kg ip in mice in the maximal electroshock screen and was chosen for further evaluation.
- Musso, David L.,Mehta, Nariman B.,Soroko, Francis E.
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- Facile Hydrodehalogenation with H2 and Pd/C Catalyst under Multiphase Conditions. 2. Selectivity and Kinetics
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Hydrodehalogenation of polyhalogenated aromatics with Pd/C catalyst carried out in the presence of a quaternary onium salt follows zero-order kinetics in the substrate and first-order kinetics in the Pd/C catalyst; the related rate constants were determined for o-, m- and p-bromotoluenes, o-, m- and p-chloroalkylbenzenes (methyl, ethyl, and propyl derivatives), and other aryl halides.Reaction rates, depending on the aromatic to be reduced, may be strongly enhanced by the presence of quaternary onium salts: the isomeric chloroethylbenzenes were reduced 50 times faster when operating in the presence of Aliquat 336 (1).Also the hindered 2-chloro-m-xylene easily yielded m-xylene.The cocatalyst onium salts operate by being adsorbed on the Pd/C surface, as shown when kinetic constants are reported by varying the onium salt amount: classical Langmuir adsorption isotherms are observed.The presence of the onium salt may also influence selectivity in the reduction of isomeric aryl halides: when 1 is present, p-dichlorobenzene reacts in diethyl ether at 20 deg C, 5-fold slower than the ortho isomer; whereas the reduction rates of the two compounds are almost the same in its absence.
- Marques, Carlos Alberto,Selva, Maurizio,Tundo, Pietro
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p. 3830 - 3837
(2007/10/02)
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- Therapeutically useful 1-phenyl-2-piperidinoalkanol derivatives
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Compounds of the formula: STR1 wherein R1 is hydrogen, halogen, trifluoromethyl, alkyl, hydroxyl, alkyoxy, benzyloxy, alkanoyloxy, or benzoyloxy, or when R2 is hydroxyl or methoxy in the 4-position and R3 is hydrogen, R1 may also represent hydroxymethyl carbamoyl or alkoxycarbonyl, R2 is hydrogen, halogen, alkyl, hydroxyl, or alkoxy, R3 is hydrogen or alkyl, R4 is alkyl (in which case the compounds are (±)-erythro) or when R3 represents hydrogen, R4 may also be hydrogen, and R5 is hydrogen, halogen, alkyl, alkoxy, or three methoxy groups in the 3-, 4- and 5-positions and pharmaceutically acceptable acid addition salts thereof, with the exclusion of compounds wherein: (a) one of R1 and R2 is in the 4-position and is hydroxyl, alkoxy or benzyloxy, the other is in the 3-position and is hydrogen, hydroxyl, alkoxy or benzyloxy, and R3 and R5 are hydrogen and wherein: (b) R1 is in the 4-position and is halogen, R4 is methyl and R2, R3 and R5 are hydrogen, are useful as medicaments.
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