- Photocatalytic oxidation of alkanes with dioxygen by visible light and copper(II) and iron(III) chlorides: Preference oxidation of alkanes over alcohols and ketones
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Visible light irradiation of alkanes in acetonitrile with CuCl2 and FeCl3 catalysts under atmospheric dioxygen gave the corresponding alcohols and ketones effectively; in these reactions, the total selectivity of the products did not decrease so much with increase of alkane conversion. For example, cyclohexanol and cyclohexanone were formed with ca. 70% selectivity at 50% conversion, because overoxidation of the products took place more slowly than cyclohexane oxidation. The relative reactivity values of cycloalkanes increased as their ring-sizes decreased. In the oxidation of hexane, the reactivity ratio of C1-/C2-/C3-H was found to be 1.0/1.4/1.8 with CuCl2 and 1.0/4.6/6.6 with FeCl3, respectively. Toluene and diphenylmethane were more reactive than cyclohexane with FeCl3, as expected, whereas the alkane was oxidized faster than the benzylic compounds in the separate reaction with CuCl2. Moreover, the alkane oxidation could be comparably performed by sunlight instead of an artificial lamp.
- Takaki, Ken,Yamamoto, Jun,Komeyama, Kimihiro,Kawabata, Tomonori,Takehira, Katsuomi
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- An experimental and theoretical study on imidazolium-based ionic liquid promoted chloromethylation of aromatic hydrocarbons
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The chloromethylation of aromatic hydrocarbons proceeded efficiently using the reusable imidazolium-based ionic liquid as promoter. Mild reaction conditions, enhanced rates, improved yields, recyclability of ionic liquids, and reagents' reactivity which is different from that in conventional organic solvents are the remarkable features observed in ionic liquids. The ionic liquids were recycled in three subsequent runs with no decrease in activity. In addition, the results of calculations with the Gaussian 98 suite of program are in good accordance with the experimental outcomes.
- Wang, Yun,Xi, Yanli
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- Trichloroisocynuric acid/DMF as efficient reagent for chlorodehydration of alcohols under conventional and ultrasonic conditions
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A new and efficient method for the chlorodehydration of alcohols utilizing TCCA/DMF is described. Various alcohols can be converted smoothly into their corresponding alkyl chlorides in high yields under mild conditions with short reaction times. Taylor & Francis Group, LLC.
- Venkana, Purugula,Kumar, Mukka Satish,Rajanna, Kamatala Chinna,Ali, Mir Moazzam
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- Vitamin B12 Catalyzed Atom Transfer Radical Addition
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Vitamin B12, a natural Co-complex, catalyzes atom transfer radical addition (ATRA) of organic halides to olefins. The established conditions were found to be very selective, with atom transfer radical polymerization (ATRP) occurring only in the case of acrylates.
- Proinsias, Keith O.,Jackowska, Agnieszka,Radzewicz, Katarzyna,Giedyk, MacIej,Gryko, Dorota
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- Chloroalkylation of aryl aldehydes using alkylboron dichlorides in the presence of oxygen
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Reactions of aryl aldehydes with alkylboron dichlorides in the presence of oxygen at room temperature produces arylalkyl chlorides in good to excellent yields.
- Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
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- Reactivity of [WCl6] with Ethers: A Joint Computational, Spectroscopic and Crystallographic Study
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The reactions of [WCl6] with a series of ethers have been performed in chlorinated solvent and elucidated by means of analytical, spectroscopic and DFT methods. The addition of tetrahydropyran (thp) or 1,4-dioxane to [WCl6] resulted in the reversible formation of the adducts WCl6···L [L = thp (1a), 1,4-dioxane (1b)], detected in solution by NMR spectroscopy. The reaction of [WCl6] with thp in a molar ratio of 1:2 in chloroform at reflux afforded [WOCl4(thp)] (2a), which was isolated in 51 % yield. [WOCl4(OMe2)] (2b) and [WOCl3(OMe2)2] (3a) were isolated in yields of 53 and 18 %, respectively, from the reaction of [WCl6] with an excess of dimethyl ether. [WOCl3(OEt2)2] (3b) was the only identified metal compound produced from the reaction of [WCl6] and OEt2(1:2 molar ratio). According to NMR studies, the oxide ligand in 2a,b and 3a,b was generated by double C–O bond cleavage involving one equivalent of organic reactant. The 1:1 reaction of [WCl6] with 1,2-diethoxyethane led to [WCl5(κ1-OCH2CH2OEt)] (4) and a minor amount of [WCl4(κ2-EtOCH2CH2OEt)] (5). The aryl oxide compound [WCl5(OPh)] (6) was prepared in 62 % yield from the reaction of [WCl6] and anisole by selective Csp3–O bond activation. The prolonged heating of a mixture of [WCl6] and diphenyl ether in 1,2-dichloroethane led to the isolation of the WVcomplex [WCl5(OPh2)] (7). The molecular structures of 2a and 3a were ascertained by X-ray diffraction.
- Bortoluzzi, Marco,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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- Chlorination of aromatic compounds with chlorous acid under non-aqueous conditions
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The non-aqueous solution of chlorous acid is a versatile chlorinating agent for aromatic compounds, e.g. alkylbenzenes, anisoles, and acetanililides. It is also an effective chlorine-substitute for the conversion of aryl bromides into aryl chlorides under mild conditions. The stoichiometry of the chlorination reaction is ArH+3HOClO→ArCl+2ClO2+2H2O, and the mode of dissociation of chlorous acid in dichloromethanc is 3HOClO→HOCl+2ClO2+H2O.
- Muathen, Hussni A.
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- Diphenylphosphinated Ethylene Oligomers as polymeric Reagents for Synthesis of Alkyl Chlorides from Alcohols
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Diphenylphosphinated ethylene oligomers can be used as homogeneous polymeric reagents at 90 deg C in carbon tetrachloride to form alkyl chlorides from alcohols and since these funcionalized ethylene oligomers precipitate quantitatively from solution at 25 deg C, they can be easily recovered and separated from the reaction products and can be partially recycled.
- Bergbreiter, David E.,Blanton, James R.
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- The Hexachlorocerate(III) Anion: A Potent, Benchtop Stable, and Readily Available Ultraviolet A Photosensitizer for Aryl Chlorides
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The hexachlorocerate(III) anion, [CeIIICl6]3-, was found to be a potent photoreductant in acetonitrile solution with an estimated excited-state reduction potential of - 3.45 V versus Cp2Fe0/+. Despite a short lifetime of 22.1(1) ns, the anion exhibited a photoluminescence quantum yield of 0.61(4) and fast quenching kinetics toward organohalogens allowing for its application in the photocatalytic reduction of aryl chloride substrates.
- Yin, Haolin,Jin, Yi,Hertzog, Jerald E.,Mullane, Kimberly C.,Carroll, Patrick J.,Manor, Brian C.,Anna, Jessica M.,Schelter, Eric J.
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- The selective functionalization of saturated hydrocarbons. Part 47, investigation of the size of the reagent involved in the Fe(II)-Fe(IV) manifold
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Competition experiments between cyclohexane and various aromatic substrates have been carried out in pyridine-acetonitrile in order to ascertain the steric requirements of the Fe(II)-H2O2 reagent in comparison with the Fe(III)-H2O2 reagent already studied. The latter is distinctly larger and much less reactive than the former. Although these results might indicate that the Fe(II)H2O2 reagent is simply the hydroxyl radical, the chemistry observed is strictly dependent on the presence of picolinic acid. Without the latter, no significant oxidation of any substrate is observed. Hydroxyl radical formation (Fenton Chemistry) is not considered to be ligand dependent in preceding investigations.
- Barton, Derek H.R.,Launay, Franck
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- A convenient method for producing mono- and dichlorohydrins from glycerol
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A new method for the transformation of glycerol into mono- and dichlorohydrins has been studied. With trimethylchlorosilane as chlorinating agent and acetic acid as catalyst, mono- and dichlorohydrins have been obtained in high yields and selectivity. In fact, under different reaction conditions, the synthesis of α-monochlorohydrin (3-chloropropan-1,2-diol) or α,γ-dichlorohydrin (1,3-dichloropropan-2-ol) as predominant product has been achieved. This process was also exploited for the valorisation of the crude mixture of glycerol and monochlorohydrin (glyceric mixture), a by-product from an earlier BioDiesel production. A reaction mechanism has been proposed based on investigations on the chlorination of different alcohols.
- Giomi, Donatella,Malavolti, Marino,Piccolo, Oreste,Salvini, Antonella,Brandi, Alberto
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- Phase Transfer Catalysts Based on Sucrose Ethyleneoxide Adducts
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Sucrose ethyleneoxide adducts have been prepared by reaction of sucrose with various amounts of ethyleneoxide in DMSO.The resulting polypode molecules were found to be efficient phase transfer catalysts in nucleophilic substitutions, oxidation and dichlorcarbene generation.Polymerisable polypodes have been obtained by reaction of sucrose ethyleneoxide adducts with methacrylic anhydride or methacryloylchloride in pyridine.Free radical polymerisation of the resulting mixtures of mono- and polyfunctional methacrylic esters of sucrose ethyleneoxide adducts yielded crosslinked gels.These polymer-supported "octopus-molecules" were found to be efficient triphase catalysts. - Keywords: Polypode ligand as phase transfer catalyst; Polypode ligand, polymer supported
- Gruber, Heinrich,Greber, Gerd
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- Kinetic study of the reactions of chlorine atoms and Cl2.- radical anions in aqueous solutions. II. Toluene, benzoic acid, and chlorobenzene
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The reactions of chlorine atoms and Cl2.- radical ions with toluene, benzoic acid, and chlorobenzene were studied using laser conventional flash photolysis of Na2S2O8 aqueous solutions containing Cl- ions. The reaction rate constants was diffusion-controlled, thus showed no dependence on the σ-Hammett parameter of the substituent in the aromatic ring. The high reactivity of Cl atoms was distinct with that of Cl2.- radical ions, for which the rate constants for the reactions with the substituted benzenes were -/M-sec. The π-complex of benzene yielded very low bond energies (a sequence of chemical reactions unless highly stabilized by the solvent. An electron-transfer reaction pathway was not important for the substrates benzene, toluene, and benzoic acid since phenolic derivatives formed from the disproportionation of HO-CHD radicals were not observed as reaction products. The dissimilarity in the behavior of the Cl-CHD radicals in the gas phase and in organic solvents compared with that in the aqueous phase seemed to be the lack of dissociation of Cl-CHD in aqueous solutions.
- Martire,Bertolotti,Carrillo Le Roux,Braun,Rosso,Bertolotti,Carrillo Le Roux,Braun,Gonzalez
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- Kinetics of the gas-phase elimination reaction of benzyl chloroformate and neopentyl chloroformate
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The gas-phase eliminations of benzyl chloroformate (475-523 K, 31-103 Torr) and neopentyl chloroformate (563-622 K, 37-70 Torr), in a deactivated static reaction vessel, and in the presence of a free radical suppressor, are homogeneous, unimolecular, and follow a first-order rate law. The rate coefficients are expressed by the following Arrhenius equations: Benzyl chloroformate log κI = (13.30 ± 0.38) - (152.9 ± 3.6) kJ mol-1(2.303RT)-1; r = 0.9989 Neopentyl chloroformate Formation of neopentyl chloride: log κI = (14.29 ± 0.48) - (196.3 ± 5.5) kJ mol-1(2.303RT)-1; r = 0.9986 Formation of 2-methylbutenes: log κII = (12.12 ± 0.73) - (178.2 ± 8.3) kJ mol-1(2.303RT)-1; r = 0.9960 The derived kinetic and thermodynamic parameters for benzyl chloroformate decomposition indicate the reaction proceeds through a concerted four-membered cyclic transition state to give benzyl chloride and CO2 gas. Neopentyl chloroformate undergoes a parallel reaction, where neopentyl chloride formation may arise from a polar-concerted four-membered cyclic transition state, whereas the mixture of olefins, 2-methyl-2-butene, and 2-methyl-1-butene appears to be produced from a carbene intermediate. This intermediate seems to be originated from a concerted five-membered cyclic transition state of the neopentyl substrate.
- Lezama, Jesus,Domnguez, Rosa M.,Chuchani, Gabriel
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- Selective Cross Coupling via Oxovanadium(V)-Induced Oxidative Desilylation of Benzylic Silanes
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Benzylic silanes bearing an electron-donating group at the ortho- or para-position underwent the oxovanadium(V)-induced one-electron oxidative desilylation due to low ionization potential, which was applied to the intermolecular regioselective coupling with allylic silanes or silyl enol ether.
- Hirao, Toshikazu,Fujii, Takashi,Ohshiro, Yoshiki
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- The halogenation of aliphatic C-H bonds with peracetic acid and halide salts
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Hydrocarbons react with molar concentrations of peracetic acid and halide salts to yield predominantly monohalogenated products under optimum conditions, with chlorination being more oxidatively efficient than bromination. The alkane halogenation proceeds at ambient temperature and does not require a heavy-metal catalyst. The observed reactivity is consistent with a radical mechanism, in which the peracid initially reacts with the halide ions to yield halogen-atom radicals, which ultimately oxidize the hydrocarbon. Although the reactivity proceeds slightly more efficiently in acetonitrile, the halogenation protocol works well in water.
- He, Yu,Goldsmith, Christian R.
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- Medium and Structure Effects on the Anodic Oxidation of Aryl Arylmethyl Sulfides
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The anodic oxidation of a number of XC6H4CH2SC6H4Y has been investigated under a variety of conditions (AcOH/AcO(1-), AcOH/NO3(1-), AcOH/ClO4(1-), CH3CN/ClO4(1-) and the relative weight of the various reaction paths available to the intermediate radical cation (Cα-H deprotonation, C-S bond cleavage, attack on sulfur) evaluated via product analysis.It has been observed that in AcOH/AcO(1-) (presence of a strong base) the main reaction is Cα-H deprotonation, which is also favored when X is an electron-withdrawing substituent and depressed by electron-donating Y.The C-S bond cleavage reaction is particularly important in CH3CN/ClO4(1- ); its relative contribution is enhanced by an electron-donating X, which makes the benzyl carbocation more stable.The pathway leading to sulfoxides is favored in AcOH/NO3(1-) and, to a lesser extent, in AcOH/ClO4(1-).Formation of sulfoxide is also favored when Y is an electron-donating group.
- Baciocchi, Enrico,Rol, Cesare,Scamosci, Emanuela,Sebastiani, Giovanni V.
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- Practical conversion of chlorosilanes into alkoxysilanes without generating HCl
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Alcohol-free: A versatile, efficient, and practical synthesis of alkoxysilanes without generation of HCl involves the reaction of chlorosilanes with unsymmetrical ethers in the presence of a Lewis acid (see scheme). The reaction proceeds through selective cleavage of C-O bonds and is superior to conventional processes. Industrially feasible reagents are used and only one by-product results. Copyright
- Wakabayashi, Ryutaro,Sugiura, Yasushi,Shibue, Toshimichi,Kuroda, Kazuyuki
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- Astonishing alkylation and unusual reduction reactions of anionic titanium(II) isopropoxide complexes: Evidence for SET processes in transition-metal oxidative additions
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A mixture of titanium(II) isopropoxide and lithium isopropoxide (1:2), generated in THF by the treatment of titanium(IV) isopropoxide with two equivalents of n-butyllithium, has been shown to be an unexpected alkylating agent as well as an unusual reducing agent for a wide variety of organic substrates. Since titanium(II) isopropoxide, which is free of any lithium isopropoxide, neither causes alkylation of any of the same substrates nor is such a powerful reductant, it is proposed that the lithium isopropoxide activates titanium(II) isopropoxide for such unusual reactions by the formation of the lithium salt coordination complex Li2Ti[OiPr]4. Illustrative of the unprecedented alkylations are the transformations, after hydrolysis, of various substituted benzonitriles to isopropyl-substituted phenyl ketones, of (dichloromethyl)benzene to, principally, 2-methyl-1-phenyl-1-propene and of (trichloromethyl)benzene to isopropyl phenyl ketone. By comparing the reducing actions of Li2Ti[OiPr]4 and Ti[OiPr]2 individually, it has been shown that, generally, the lithium salt is the more powerful reductant for epoxides, benzylic halides and conjugated olefins. From the reactions of Li2Ti[OiPr]4 with the benzonitriles, styrene, the isomeric stilbene oxides and cis-stilbene, cogent evidence is marshaled for the operation of SET processes, sensitive to steric hindrance, in such alkylations and reductions. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Eisch, John J.,Gitua, John N.
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- Competing reactions of secondary alcohols with sodium hypochlorite promoted by phase-transfer catalysis
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(Chemical Equation Presented) With aqueous hypochlorite and a phase transfer catalyst, secondary alcohols undergo hitherto unreported free radical reactions that compete with and effectively limit traditional ketone syntheses. Product mixture profiles are determined by reactant ratios, organic cosolvent, and availability of oxygen to the system. Under argon, over half of substrate alcohols, PhCH(OH)R, are converted to benzaldehyde and free radical products through β-scission of intermediate alkyl hypochlorites. Secondary alcohols with R containing three or more carbons also may undergo δ chlorination.
- Bright, Zack R.,Luyeye, Cedric R.,Morton, Angela Ste. Marie,Sedenko, Marina,Landolt, Robert G.,Bronzi, Matthew J.,Bohovic, Katherine M.,Gonser, M. W. Alex,Lapainis, Theodore E.,Hendrickson, William H.
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- BiCl3 : An efficient agent for selective chlorination of alcohols or for halogen exchange reaction
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BiCl3 was found to be an effective reagent for an improved chlorination of alcohols and for a convenient halogen exchange reaction.
- Boyer, Bernard,Keramane, El Mehdi,Montero, Jean-Louis,Roque, Jean-Pierre
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- NICKEL(SALEN) CATALYSED CHLORINATION OF SATURATED HYDROCARBONS BY SODIUM HYPOCHLORITE
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In the presence of nickel(salen) as the catalyst, basic (pH 11) aqueous solutions of sodium hypochlorite chlorinate saturated hydrocarbons under very mild conditions.
- Querci, Cecilia,Strogolo, Sauro,Ricci, Marco
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- Thermal Decomposition of Allylbenzene Ozonide
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Thermal decomposition of allylbenzene ozonide (ABO) at 98 deg C in the liquid phase yields toluene, bibenzyl, phenylacetaldehyde, formic acid, and (benzyloxy)methyl formate as major products; benzyl chloride is formed when chlorinated solvents are employe
- Ewing, James C.,Church, Daniel F.,Pryor, William A.
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- The chemistry of cyclic carbaphosphazenes: The first observation of (R 2PN)(ClCN)2 (R=Cl, Ph) as a reagent for the conversion of alcohols to aldehydes, ketones, and alkyl chlorides
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The oxidation of nine primary and secondary alcohols to the corresponding aldehydes and ketones has been carried out under mild conditions and in good yields using the cyclocarbaphosphazenes (R2PN)(ClCN)2 [R2P = Cl2 P(1), Ph2P(2)] along with dimethylsulfoxide. While both the P-Cl and C-Cl bonds of the carbaphosphazene can in principle bring about the reaction, we observed an increased preference for the C-Cl bonds over the P-Cl bonds in the oxidation of alcohol. Blocking the reactive P site on the heterocyclic ring with the phenyl groups was found to reduce the yields of the oxidized products, while blocking the C- sites with diethylamino groups resulted in no reaction. In addition, along with DMF, the same cyclocarbaphosphazene has been found to be useful for the conversion of alcohols to alkyl chlorides. Copyright Taylor & Francis Group, LLC.
- Behera, Nabakrushna,Mishra, Pradyumna Kumar,Elias, Anil J.
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- Silica Chloride (SiO2-Cl), a New Heterogeneous Reagent, for the Selective and Efficient Conversion of Benzylic Alcohols to Their Corresponding Chlorides and Iodides
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Structurally different benzylic alcohols were efficiently converted to their corresponding chlorides by silica chloride (SiO2-Cl) in CHCl3 at room temperature. Silica chloride is also able to convert benzylic alcohols to their iodides in the presence of NaI in a mixture of CH3CN/CHCl3 in excellent yields.
- Firouzabadi, Habib,Iranpoor, Naser,Karimi, Babak,Hazarkhani, Hassan
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- Discovery of novel quinazolinone derivatives as potential anti-HBV and anti-HCC agents
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As a continuation of earlier works, a series of novel quinazolinone derivatives (5a-s) were synthesized and evaluated for their in vitro anti-HBV and anti-hepatocellular carcinoma cell (HCC) activities. Among them, compounds 5j and 5k exhibited most potent inhibitory effect on HBV DNA replication in both drug sensitive and resistant (lamivudine and entecavir) HBV strains. Interestingly, besides the anti-HBV effect, compound 5k could significantly inhibit the proliferation of HepG2, HUH7 and SK- cells, with IC50 values of 5.44, 6.42 and 6.75 μM, respectively, indicating its potential anti-HCC activity. Notably, the in vitro anti-HCC activity of 5k were more potent than that of positive control 5-fluorouracil and sorafenib. Further studies revealed that compound 5k could induce HepG2 cells apoptosis by dose-dependently upregulating Bad and Bax expression and decreasing Bcl-2 and Bcl-xl protein level. Considering the potent anti-HBV and anti-HCC effect, compound 5k might be a promising lead to develop novel therapeutic agents towards HBV infection and HBV-induced HCC.
- Qiu, Jingying,Zhou, Qingqing,Zhang, Yinpeng,Guan, Mingyu,Li, Xin,Zou, Yueting,Huang, Xuan,Zhao, Yali,Chen, Wang,Gu, Xiaoke
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- Catalytic dehydrative etherification and chlorination of benzyl alcohols in ionic liquids
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Dibenzyl ethers and benzyl chloride can be obtained in moderate to excellent yields through Pd-catalysed reactions in hydrophobic ionic liquids using microwave or conventional heating. The Royal Society of Chemistry 2009.
- Kalviri, Hassan A.,Petten, Chad F.,Kerton, Francesca M.
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- Convenient One-Pot Synthesis of Sulfonyl Chlorides from Thiols Using Sulfuryl Chloride and Metal Nitrate
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Various sulfonyl chlorides were obtained in excellent yields by the reaction of alkyl and aryl thiols with sulfuryl chloride in the presence of metal nitrate under mild condition in aprotic solvents such as acetonitrile and N,N-dimethylformamide.
- Park, Young Jun,Shin, Hyun Ho,Kim, Yong Hae
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- A Kinetic and Mechanistic Study of the Self-Reaction and Reaction with H2O of the Benzylperoxy Radical
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The kinetics and mechanism of the reactions C6H5CH2O2 + C6H5CH2O2 -> 2C6H5CH2O + O2 (3a), C6H5CH2O2 + C6H5CH2O2 -> C6H5CHO + C6H5CH2OH + O2 (3b), and C6H5CH2O2 + HO2 -> C6H5CH2OOH + O2 (4) have been investigated using two complementary techniques: flash photolysis/UV absorption for kinetic measurements and continuous photolysis/FTIR spectroscopy for end-product analyses and branching ratio determinations.The reaction of chlorine atoms with toluene was found to yield benzyl radicals exclusively and was used to generate benzylperoxy radicals in excess oxygen.During this study, relative reaction rate constants of chlorine atoms with compounds related to those involved in the reaction mechanism have been measured at room temperature: k(Cl+toluene) = (6.1 +/- 0.2)E-11, k(Cl+benzaldehyde) = (9.6 +/- 0.4)E-11, k(Cl+benzyl chloride) = (9.7 +/- 0.6)E-12, k(Cl+benzyl alcohol) = (9.3 +/- 0.5)E-11, k(Cl+benzene) 3 molecule-1 s-1.The products identified following the self-reaction 3 were benzaldehyde, benzyl alcohol, and benzyl hydroperoxide.The latter is the product of the reaction of C6H5CH2O2 with HO2.The yield of products allowed us to determine the branching ratio α = k3a/k3 = 0.4.The UV absorption spectrum of the benzylperoxy radical was determined from 220 to 300 nm.It was similar to those of alkylperoxy radicals, with a maximum cross section at 245 nm of 6.8E-18 cm2 molecule-1.Kinetic data were obtained from the detailed simulation of experimental decay traces recorded at 250 nm over the temperature range 273-450 K.The resulting rate expression are k3 = (2.75 +/- 0.15)E-14 exp cm3 molecule-1 a-1 and k4 = (3.75 +/- 0.32)E-13 exp3 molecule-1 s-1 (errors = 1?).The UV absorption traces in the flash-photolysis kinetic study were well accounted for by the identified products in the FTIR study, thus providing good confidence in the results.However, about 20percent of the products have remained unidentified.Some uncertainties persist in the reaction mechanism leading us to assign a fairly large uncertainty of about 50percent to the rate constants k3 and k4 over the whole temperature range.This work shows that the aromatic substituent does not provide any specificity in the reactivity of peroxy radicals and confirms that large radicals tend to react faster with HO2 than generally assumed in current atmospheric models.
- Noziere, Barbara,Lesclaux, Robert,Hurley, Michael D.,Dearth, Mark A.,Wallington, Timothy J.
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- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
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supporting information
p. 8413 - 8418
(2021/11/01)
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- One-Pot Synthesis of Thiocarbamates
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An efficient isocyanide-based synthesis of S-thiocarbamates was discovered and thoroughly investigated. The new reaction protocol is a one-pot procedure and allows the direct conversion of N-formamides into thiocarbamates by initial dehydration with p-toluene sulfonyl chloride to the respective isocyanide and subsequent addition of a sulfoxide component. Contrary to recent literature, which also uses isocyanides as starting material, but with other sulfur reagents than sulfoxides, in this protocol, no isolation and purification of the isocyanide component is necessary, thus significantly decreasing the environmental impact and increasing the efficiency of the synthesis. The new protocol was applied to synthesize a library of sixteen thiocarbamates, applying four N-formamides and four commercially available sulfoxides. Furthermore, experiments were conducted to investigate the reaction mechanism. Finally, four norbornene-based thiocarbamate monomers were prepared and applied in controlled ring-opening metathesis polymerization (ROMP) reactions. The polymers were characterized by size-exclusion chromatography (SEC) and their properties were investigated utilizing differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
- Barther, Dennis,Malliaridou, Triantafillia,Meier, Michael A. R.,Moatsou, Dafni,Waibel, Kevin A.
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supporting information
p. 4508 - 4516
(2021/08/30)
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- Visible Light-Catalyzed Benzylic C-H Bond Chlorination by a Combination of Organic Dye (Acr+-Mes) and N-Chlorosuccinimide
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By combining "N-chlorosuccinimide (NCS)"as the safe chlorine source with "Acr+-Mes"as the photocatalyst, we successfully achieved benzylic C-H bond chlorination under visible light irradiation. Furthermore, benzylic chlorides could be converted to benzylic ethers smoothly in a one-pot manner by adding sodium methoxide. This mild and scalable chlorination method worked effectively for diverse toluene derivatives, especially for electron-deficient substrates. Careful mechanistic studies supported that NCS provided a hydrogen abstractor "N-centered succinimidyl radical,"which was responsible for the cleavage of the benzylic C-H bond, relying on the reducing ability of Acr?-Mes.
- Xiang, Ming,Zhou, Chao,Yang, Xiu-Long,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 9080 - 9087
(2020/08/14)
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- Nickel catalyzed deoxygenative cross-coupling of benzyl alcohols with aryl-bromides
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A nickel-catalyzed cross-electrophile coupling of benzyl alcohols with aromatic bromides has been developed. This deoxygenative cross-coupling occurs under mild reaction conditions at ambient temperature affording diarylmethanes, or 1,3-diarylpropenes from benzyl allyl alcohols. The system demonstrated good chemoselectivity tolerating an assortment of reactive functional groups.
- Kumar Chenniappan, Vinoth,Peck, Devin,Rahaim, Ronald
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- Thiourea-Mediated Halogenation of Alcohols
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The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
- Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
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p. 12901 - 12911
(2020/11/26)
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- Palladium-catalyzed ionic liquid-accelerated oxidative annulation of acetylenic oximes with unactivated long-chain enols
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A palladium-catalyzed ionic liquid-accelerated oxidative cascade annulation/functionalization of acetylenic oximes with unactivated long-chain enols under aerobic conditions was accomplished. This newly developed protocol provides the rapid and straightforward synthetic strategy for the assembly of structurally diverse isoxazole architectures under mild conditions with high atom- and step-economy and exceptional functional group tolerance. Notably, the ionic liquid acts as not only a solvent in the reaction but also provides the excess halide ions to eliminate hydrochloride from acetylenic oximes. Moreover, this catalytic system could be recycled up to eight times and reused without significant loss of the catalytic activity.
- Hu, Miao,Jiang, Huanfeng,Li, Jianxiao,Lin, Zidong,Wu, Wanqing
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supporting information
p. 5584 - 5588
(2020/09/21)
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- A palladium-catalyzed oxidative aminocarbonylation reaction of alkynone: O -methyloximes with amines and CO in PEG-400
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A palladium-catalyzed oxidative aminocarbonylation of O-methyloximes and amines under aerobic conditions with PEG-400 as an environmentally benign medium was accomplished. This novel protocol provides the first straightforward synthetic method for the assembly of structurally diverse 4-carboxamide isoxazoles with high atom- and step-economy and exceptional functional group tolerance. Notably, the employment of ionic liquids as an additive, with air as the sole oxidant, without ligands is an attractive feature of the present approach.
- Li, Jianxiao,Yu, Junsheng,Xiong, Wenfang,Tang, Hao,Hu, Miao,Wu, Wanqing,Jiang, Huanfeng
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p. 465 - 470
(2020/02/13)
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- Method for preparing photoinitiator, namely TPO and simultaneously preparing byproduct, namely benzyl chloride
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The invention provides a method for preparing a photoinitiator, namely TPO and simultaneously preparing a byproduct, namely benzyl chloride. The method provided by the invention avoids the problem ofrecovery of a large amount of organic waste gas, namely chloroethane and the like in production of the TPO, and also avoids the problem of serious pollution caused by a large amount of the byproduct,namely chlorine in production of the benzyl chloride. The benzyl chloride is an important chemical raw material for preparing a photoinitiator 369, so the method disclosed by the invention greatly reduces the production cost. Meanwhile, the whole process is low in preparation cost, simple in operation process, safe and easily-controllable in reaction process and easy to realize large-scale production.
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Paragraph 0021-0027
(2020/06/02)
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- PROCESS FOR THE HALOGENATION AT THE ALPHA-H POSITION OF ALKYLARENES VARIOUSLY SUBSTITUTED ON THE AROMATIC RING
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A process that allows halogenation at the alpha-H position of alkylarenes, optionally further substituted on the aromatic or heteroaromatic ring, is described.
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Page/Page column 5
(2019/05/10)
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- N -Hydroxyphthalimide/benzoquinone-catalyzed chlorination of hydrocarbon C-H bond using N -chlorosuccinimide
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The direct chlorination of C-H bonds has received considerable attention in recent years. In this work, a metal-free protocol for hydrocarbon C-H bond chlorination with commercially available N-chlorosuccinimide (NCS) catalyzed by N-hydroxyphthalimide (NHPI) with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) functioning as an external radical initiator is presented. Aliphatic and benzylic substituents and also heteroaromatic ones were found to be well tolerated. Both the experiments and theoretical analysis indicate that the reaction goes through a process wherein NHPI functions as a catalyst rather than as an initiator. On the other hand, the hydrogen abstraction of the C-H bond conducted by a PINO species rather than the highly reactive N-centered radicals rationalizes the high chemoselectivity of the monochlorination obtained by this protocol as the latter is reactive towards the C(sp3)-H bonds of the monochlorides. The present results could hold promise for further development of a nitroxy-radical system for the highly selective functionalization of the aliphatic and benzylic hydrocarbon C-H.
- Li, Zi-Hao,Fiser, Béla,Jiang, Biao-Lin,Li, Jian-Wei,Xu, Bao-Hua,Zhang, Suo-Jiang
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supporting information
p. 3403 - 3408
(2019/04/01)
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- α-Diimine-Niobium Complex-Catalyzed Deoxychlorination of Benzyl Ethers with Silicon Tetrachloride
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α-Diimine niobium complexes serve as catalysts for deoxygenation of benzyl ethers by silicon tetrachloride (SiCl4) to cleanly give two equivalents of the corresponding benzyl chlorides, where SiCl4 has the dual function of oxygen scavenger and chloride source with the formation of a silyl ether or silica as the only byproduct. The reaction mechanism has two successive trans-etherification steps that are mediated by the niobium catalyst, first forming one equivalent of benzyl chloride along with the corresponding silyl ether intermediate that undergoes the same reaction pathway to give the second equivalent of benzyl chloride and silyl ether.
- Parker, Bernard F.,Hosoya, Hiromu,Arnold, John,Tsurugi, Hayato,Mashima, Kazushi
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supporting information
p. 12825 - 12831
(2019/10/19)
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- Assessment of quinazolinone derivatives as novel non-nucleoside hepatitis B virus inhibitors
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Hepatitis B virus (HBV)infection is a worldwide public health issue. Search for novel non-nucleoside anti-HBV agents is of great importance. In the present study, a series of quinazolinones derivatives (4a-t and 5a-f)were synthesized and evaluated as novel anti-HBV agents. Among them, compounds 5e and 5f could significantly inhibit HBV DNA replication with IC50 values of 1.54 μM and 0.71 μM, respectively. Interestingly, the selective index values of 5f was higher than that of lead compound K284–1405, suggesting 5f possessed relatively safety profile than K284–1405. Notably, 5e and 5f exhibited remarkably anti-HBV activities against lamivudine and entecavir resistant HBV strain with IC50 values of 1.90 and 0.84 μM, confirming their effectiveness against resistant HBV strain. In addition, molecular docking studies indicated that compounds 5e and 5f could well fit into the dimer-dimer interface of HBV core protein dominated by hydrophobic interactions. Notably, their binding modes were different from the lead compound K284–1405, which may be attributed to the additional substituent groups in the quinazolinone scaffold. Taken together, 5e and 5f possessed novel chemical structure and potent anti-HBV activity against both drug sensitive and resistant HBV strains, thus warranting further research as potential non-nucleoside anti-HBV candidates.
- Qiu, Jingying,Chen, Wang,Zhang, Yinpeng,Zhou, Qingqing,Chen, Jing,Yang, Lihua,Gao, Jian,Gu, Xiaoke,Tang, Daoquan
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- An efficient and convenient chloromethylation of some aromatic compounds catalyzed by zinc iodide
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Treatment of a series of aromatic hydrocarbons and O-carbethoxy phenol substrates with a mixture of chlorosulfonic acid and dimethoxymethane in CH2Cl2 catalyzed by zinc iodide affords the corresponding chloromethyl derivatives in good to excellent yields.
- Tang, Jian,Liu, Hongtao,Zhou, Jing,Zhang, Xingxian
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- A practical and convenient Blanc-type chloromethylation catalyzed by zinc chloride under solvent-free conditions
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Chloromethylation of various aromatic hydrocarbons and substituted phenolic derivatives with dimethoxymethane and chlorosulfonic acid was carried out in the presence of 10 mol% of ZnCl2 in a mild and efficient manner under solvent-free conditions. In addition, 2,6-dimethyltyrosine was synthesized in high yield via this protocol.
- Tang, Jian,Liu, Hongtao,He, Kailun,Zhang, Xingxian
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p. 925 - 932
(2019/03/17)
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- Highly Reactive Manganese(IV)-Oxo Porphyrins Showing Temperature-Dependent Reversed Electronic Effect in C-H Bond Activation Reactions
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We report that Mn(IV)-oxo porphyrin complexes, MnIV(O)(TMP) (1) and MnIV(O)(TDCPP) (2), are capable of activating the C-H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, via an oxygen non-rebound mechanism. Interestingly, 1 with an electron-rich porphyrin is more reactive than 2 with an electron-deficient porphyrin at a high temperature (e.g., 0 °C). However, at a low temperature (e.g., -40 °C), the reactivity of 1 and 2 is reversed, showing that 2 is more reactive than 1. To the best of our knowledge, the present study reports the first example of highly reactive Mn(IV)-oxo porphyrins and their temperature-dependent reactivity in C-H bond activation reactions.
- Guo, Mian,Seo, Mi Sook,Lee, Yong-Min,Fukuzumi, Shunichi,Nam, Wonwoo
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supporting information
p. 12187 - 12191
(2019/08/20)
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- Flavin Catalysis Employing an N(5)-Adduct: an Application in the Aerobic Organocatalytic Mitsunobu Reaction
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An artificial flavin system has been firstly proved to employ an N(5)-adduct for a catalytic transformation. This mode of catalysis occurs in some flavoenzymes but it is unknown in chemocatalysis, still exclusively using only C(4a)-adducts. In our report, an ethylene-bridged biomimetic flavin has been shown to participate in the Mitsunobu esterification reaction as an alternative to dialkyl azodicarboxylate. The reaction occurs via a flavin N(5)-triphenylphosphane adduct and is catalytic from the point of view of the flavin, which is regenerated by oxygen. This approach distinguishes from other catalytic Mitsunobu reaction procedures which require an extra catalytic system.
- M?rz, Michal,Babor, Martin,Cibulka, Radek
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supporting information
p. 3264 - 3268
(2019/06/08)
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- Highly selective halogenation of unactivated C(sp3)-H with NaX under co-catalysis of visible light and Ag@AgX
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The direct selective halogenation of unactivated C(sp3)-H bonds into C-halogen bonds was achieved using a nano Ag/AgCl catalyst at RT under visible light or LED irradiation in the presence of an aqueous solution of NaX/HX as a halide source, in air. The halogenation of hydrocarbons provided mono-halide substituted products with 95% selectivity and yields higher than 90%, with the chlorination of toluene being 81%, far higher than the 40% conversion using dichlorine. Mechanistic studies demonstrated that the reaction is a free radical process using blue light (450-500 nm), with visible light being the most effective light source. Irradiation is proposed to cause AgCl bonding electrons to become excited and electron transfer from chloride ions induces chlorine radical formation which drives the substitution reaction. The reaction provides a potentially valuable method for the direct chlorination of saturated hydrocarbons.
- Liu, Shouxin,Zhang, Qi,Tian, Xia,Fan, Shiming,Huang, Jing,Whiting, Andrew
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p. 4729 - 4737
(2018/10/23)
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- Manganese-salen catalyzed oxidative benzylic chlorination
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Abstract: Metalloporphyrins are well-known to serve as the model for mimicking reactivities exhibited by cytochrome P450 hydroxylase. Recent developments on selective C–H halogenation using Mn-porphyrins provided the way for understanding the reactivity as well as mechanism of different halogenase enzymes. In this report, we demonstrated a method for benzylic C–H chlorination using easily prepared Mn(salen) complex as the catalyst, which shows a complementary reactivity of Mn-porphyrins. Here, NaOCl has been used as a chlorinating source as well as the oxidant. Efforts towards understanding the mechanism suggested the formation of the high-valent Mn(V)=O species which is believed to be the key intermediate to conduct this transformation. Graphical abstract: SYNOPSIS Mn(salen)-catalyzed selective benzylic chlorination protocol has been developed using aqueous NaOCl solution. Reactions proceeded efficiently at room temperature and displayed good functional group tolerance. The mechanistic investigation demonstrated that Mn (V) = O species is likely to be the key intermediate which is responsible to generate benzylic radical. EPR and ESI-MS studies confirmed the in situ formation of Mn(IV)-species.[Figure not available: see fulltext.].
- Sasmal, Sheuli,Rana, Sujoy,Lahiri, Goutam Kumar,Maiti, Debabrata
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- NMP-mediated chlorination of aliphatic alcohols with aryl sulfonyl chloride for the synthesis of alkyl chlorides
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NMP-mediated chlorination of aliphatic alcohols has been developed for the synthesis of alkyl chlorides. This facile, efficient and practical approach used simple and readily available aryl sulfonyl chlorides as the chlorination reagent for the construction of C–Cl bond in good to excellent yields with mild conditions and broad substrate scope.
- Zheng, Dagui,Mao, Liu-Liang,Zhu, Xian-Hong,Zhou, An-Xi
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supporting information
p. 2793 - 2800
(2018/11/06)
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- Ferric(III) Chloride Catalyzed Halogenation Reaction of Alcohols and Carboxylic Acids Using α,α-Dichlorodiphenylmethane
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A new method for chlorination of alcohols and carboxylic acids, using α,α-dichlorodiphenylmethane as the chlorinating agent and FeCl3 as the catalyst, was developed. The method enables conversions of various alcohols and carboxylic acids to their corresponding alkyl and acyl chlorides in high yields under mild conditions. Particulary interesting is the observation that the respective alkyl bromides and iodides can be generated from alcohols when either LiBr or LiI are present in the reaction mixtures.
- Lee, Chang-Hee,Lee, Soo-Min,Min, Byul-Hana,Kim, Dong-Su,Jun, Chul-Ho
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supporting information
p. 2468 - 2471
(2018/04/25)
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- Photoreduction of Thioether Gold(III) Complexes: Mechanistic Insight and Homogeneous Catalysis
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Complexes formed between AuCl3 and thioether ligands underwent a photoinduced reductive elimination under homogeneous conditions in dichloromethane and toluene solutions to afford the corresponding AuI complexes. All the gold(III) complexes were rapidly reduced to the gold(I) chloride complexes under 365 nm irradiation or ambient light while being thermally stable below 55 °C. The mechanism of photoreduction through Cl2 elimination is discussed based on a kinetic study and the chemical trapping of chlorine species: Cl2, radical Cl., and possibly Cl+. The catalytic activities of the gold(III) chloride complexes and the corresponding gold(I) complexes obtained by in situ reduction were evaluated in the cyclization of N-propargylic amides to oxazoles. The merits of such photoreducible complexes in homogeneous gold catalysis are illustrated by a cascade reaction catalyzed by thioether gold complexes that affords a 4H-quinolizin-4-one in high yields.
- Cao, Zhen,Bassani, Dario M.,Bibal, Brigitte
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supporting information
p. 18779 - 18787
(2018/11/23)
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- Synthesis of benzaldehyde by swern oxidation of benzyl alcohol in a continuous flow microreactor system
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Preparation of benzaldehyde by Swern oxidation of benzyl alcohol was carried out in a continuous flow microreactor system. Dimethyl sulfoxide (Me 2 SO) was used as oxidizing agent and oxalyl chloride or p-toluenesulfonyl (p-TsCl) chloride was used as the activating agent. Benzyl alcohol was oxidized to benzaldehyde by the Me 2 SO-activating agent mixture in the continuous flow microreactor system. The optimized reaction conditions of the Swern oxidation were as follows: oxalyl chloride was used as the activating agent; the mole ratio of Me 2 SO, oxalyl chloride, and benzyl alcohol was 4:2:1; the flow rate of Me 2 SO was 1.5 mL/min; the reaction temperature was 15 ? C; length of delay loop was 1.5 m; a Caterpillar Split-Recombine Micro Mixer was used; and all of the experiments were completed at atmospheric pressure. The yield of benzaldehyde can reach 84.7% with selectivity of 98.5%. Due to the small reactor volume and short residence times, the Swern oxidation of benzyl alcohol in a continuous flow microreactor system can be operated at nearly room temperature (5–19 ? C) instead of –70 ? C in a batch reaction, with residence time of reactants in microreactors in milliseconds instead of several hours in a batch reaction.
- Zhu, Lin,Xu, Xiaohui,Zheng, Fuping
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- BBr3-Assisted Preparation of Aromatic Alkyl Bromides from Lignin and Lignin Model Compounds
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For the first time, BBr3-assisted nucleophilic substitution was applied to a variety of β-O-4 and α-O-4 model compounds for the highly effective cleavage of different C-O bonds, including C-Oα-OH, Cβ-O/Cα-O and CMe-O bonds (99% conversion for most cases). Without any pretreatment, the substitution proceeds at room temperature in the absence of any catalyst, or additive, selectively affording phenols and important organic synthesis reagents, aromatic alkyl bromides, in high to excellent yields (up to 98%). Preliminary studies also highlight the prospect of this method for the effective cleavage of different types of C-O bonds in real lignin. A total 14 wt % yield of aromatic alkyl bromide, 4-(1,2-dibromo-3-hydroxypropyl)benzene-1,2-diol (10), has been obtained from an extracted lignin through this method.
- Li, Xuan,He, Jianghua,Zhang, Yuetao
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supporting information
p. 11019 - 11027
(2018/09/06)
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- By nucleophilic substitution reaction to degrade lignin and lignin model compounds (by machine translation)
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The invention through the nucleophilic substitution reaction to degrade lignin and lignin model compound method relates to biomass energy chemical technical field. In order to lignin model compounds and organic solvent-soluble lignin as substrate, to halogenated compound B BX3 As nucleophiles, through the nucleophilic substitution reaction, in - 78 °C to 60 °C conditions, reaction 0.5 h - 36 h, at the same time realize lignin model compound, lignin degradation, and the connection of the X substituent. The operation of the invention the method is simple, mild reaction conditions, not only high conversion and high selectivity (>99% conversion rate, close to 99% [...] selective) realizes the lignin and the degradation of lignin model compound, and obtained the degradation product, is a very high can be modified with the nature contains the bromine compound, can be used as an important organic synthetic intermediates. (by machine translation)
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Paragraph 0050; 0051
(2018/04/03)
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- Development of a Robust Process for the Preparation of High-Quality 4-Methylenepiperidine Hydrochloride
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An efficient route for the preparation of 4-methylenepiperidine hydrochloride 1 was designed, and then a process feasible for large-scale production was developed with a total yield of 83.5% at a purity of 99.9%.
- Zhu, Fuqiang,Aisa, Haji A.,Zhang, Jian,Hu, Tianwen,Sun, Changliang,He, Yang,Xie, Yuanchao,Shen, Jingshan
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- Mild Aliphatic and Benzylic Hydrocarbon C-H Bond Chlorination Using Trichloroisocyanuric Acid
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We present the controlled monochlorination of aliphatic and benzylic hydrocarbons with only 1 equiv of substrate at 25-30 °C using N-hydroxyphthalimide (NHPI) as radical initiator and commercially available trichloroisocyanuric acid (TCCA) as the chlorine source. Catalytic amounts of CBr4 reduced the reaction times considerably due to the formation of chain-carrying ·CBr3 radicals. Benzylic C-H chlorination affords moderate to good yields for arenes carrying electron-withdrawing (50-85%) or weakly electron-donating groups (31-73%); cyclic aliphatic substrates provide low yields (24-38%). The products could be synthesized on a gram scale followed by simple purification via distillation. We report the first direct side-chain chlorination of 3-methylbenzoate affording methyl 3-(chloromethyl)benzoate, which is an important building block for the synthesis of vasodilator taprostene.
- Combe, Sascha H.,Hosseini, Abolfazl,Parra, Alejandro,Schreiner, Peter R.
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p. 2407 - 2413
(2017/03/11)
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- Room temperature C(sp2)-H oxidative chlorination: Via photoredox catalysis
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Photoredox catalysis has been developed to achieve oxidative C-H chlorination of aromatic compounds using NaCl as the chlorine source and Na2S2O8 as the oxidant. The reactions occur at room temperature and exhibit exclusive selectivity for C(sp2)-H bonds over C(sp3)-H bonds. The method has been used for the chlorination of a diverse set of substrates, including the expedited synthesis of key intermediates to bioactive compounds and a drug.
- Zhang, Lei,Hu, Xile
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p. 7009 - 7013
(2017/10/05)
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- Visible Light-Induced Oxidative Chlorination of Alkyl sp3 C-H Bonds with NaCl/Oxone at Room Temperature
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A visible light-induced monochlorination of cyclohexane with sodium chloride (5:1) has been successfully accomplished to afford chlorocyclohexane in excellent yield by using Oxone as the oxidant in H2O/CF3CH2OH at room temperature. Other secondary and primary alkyl sp3 C-H bonds of cycloalkanes and functional branch/linear alkanes can also be chlorinated, respectively, under similar conditions. The selection of a suitable organic solvent is crucial in these efficient radical chlorinations of alkanes in two-phase solutions. It is studied further by the achievement of high chemoselectivity in the chlorination of the benzyl sp3 C-H bond or the aryl sp2 C-H bond of toluene.
- Zhao, Mengdi,Lu, Wenjun
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supporting information
p. 4560 - 4563
(2017/09/11)
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- Method for optical catalytic conversion of toluene into chloro-toluene
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The present invention relates to a method for optical catalytic conversion of toluene into chloro-toluene. The method is as follows: first copper chloride and toluene are dissolved in acetonitrile, a cupric chloride and acetonitrile complex can absorb vis
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Paragraph 0013; 0014; 0018
(2016/10/31)
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- Direct halogenation of alcohols with halosilanes under catalyst- and organic solvent-free reaction conditions
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A chemoselective method for the direct halogenation of different types of alcohols with halosilanes under catalyst- and solvent-free reaction conditions (SFRC) is reported. Various primary, secondary and tertiary benzyl alcohols and tertiary alkyl alcohols were directly transformed to the corresponding benzyl and alkyl halides, respectively, using chlorotrimethylsilane (TMSCl) and bromotrimethylsilane (TMSBr).
- Ajvazi, Njomza,Stavber, Stojan
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supporting information
p. 2430 - 2433
(2016/05/19)
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- Continuous-Flow Multistep Synthesis of Cinnarizine, Cyclizine, and a Buclizine Derivative from Bulk Alcohols
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Cinnarizine, cyclizine, buclizine, and meclizine belong to a family of antihistamines that resemble each other in terms of a 1-diphenylmethylpiperazine moiety. We present the development of a four-step continuous process to generate the final antihistamines from bulk alcohols as the starting compounds. HCl is used to synthesize the intermediate chlorides in a short reaction time and excellent yields. This methodology offers an excellent way to synthesize intermediates to be used in drug synthesis. Inline separation allows the collection of pure products and their immediate consumption in the following steps. Overall isolated yields for cinnarizine, cyclizine, and a buclizine derivative are 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1. The incredible bulk: Bulk alcohols are converted continuously into chlorides using HCl in a microflow. A reaction network that consists of four steps and two inline separations leads to the continuous preparation of cinnarizine, cyclizine, and a buclizine derivative with yields of 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1.
- Borukhova, Svetlana,Nol, Timothy,Hessel, Volker
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- Hydrogen Chloride Gas in Solvent-Free Continuous Conversion of Alcohols to Chlorides in Microflow
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Chlorides represent a class of valuable intermediates that are utilized in the preparation of bulk and fine chemicals. An earlier milestone to convert bulk alcohols to corresponding chlorides was reached when hydrochloric acid was used instead of toxic and wasteful chlorinating agents. This paper presents the development of an intensified solvent-free continuous process by using hydrogen chloride gas only. The handling of corrosive hydrogen chloride became effortless when the operating platform was split into dry and wet zones. The dry zone is used to deliver gas and prevent corrosion, while the wet zone is used to carry out the chemical transformation. The use of gas instead of hydrochloric acid allowed a decrease in hydrogen chloride equivalents from 3 to 1.2. In 20 min residence time, full conversion of benzyl alcohol yielded 96 wt % of benzyl chloride in the product stream. According to green chemistry and engineering principles, the developed process is of an exemplary type due to its truly continuous nature, no use of solvent and formation of water as a sole byproduct.
- Borukhova, Svetlana,No?l, Timothy,Hessel, Volker
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supporting information
p. 568 - 573
(2016/03/04)
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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
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Page/Page column 60; 61; 66; 69; 74; 75; 76; 77; 78; 90; 187
(2017/01/02)
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- Iodobenzene Dichloride in the Esterification and Amidation of Carboxylic Acids: In-Situ Synthesis of Ph3PCl2
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A novel, in-situ synthesis of dichlorotriphenylphosphorane (Ph3PCl2) is accomplished upon combining PPh3and the easily prepared hypervalent iodine reagent iodobenzene dichloride (PhICl2). The phosphorane is selectively generated in the presence of carboxylic acid or alcohol residues to rapidly produce acyl chlorides and alkyl chlorides in high yields. Addition of EtOH, PhOH, BnOH, Et2NH or CH2N2results in the direct synthesis of esters, amides and diazo ketones from carboxylic acids.
- Carle, Myriam S.,Shimokura, Grace K.,Murphy, Graham K.
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supporting information
p. 3930 - 3933
(2016/08/24)
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- Preparation method of donepezil hydrochloride
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The invention relates to a compound synthesis method, in particular to a preparation method of donepezil hydrochloride. The method consists of: (1) adding thionyl chloride into benzyl alcohol dropwise and carrying out heating reaction; (2) adding anhydrous ethanol, sodium bicarbonate and 2, 3-dihydro-5, 6-dimethoxy-2-(4-piperidyl)methyl-1-indanone, carrying out reaction, cooling and pumping filtration; (3) performing washing with ethyl acetate, combining the filtrate, then conducting washing with brine, collecting the organic phase, and conducting concentration; (4) performing cooling, adding saturated hydrogen chloride ethyl acetate solution to adjust pH, further conducting stirring, filtering, washing and drying, thus obtaining a crude product; and (5) conducting dissolution with methanol, then adding activated carbon to conduct decoloration, performing cooling crystallization, carrying out filtering, washing the filter cake with methanol, then adding anhydrous ethanol and performing stirring, conducting filtration and washing, soaking the filter cake with ethyl acetate, and carrying out filtering and drying, thus obtaining a donepezil hydrochloride refined product. The method provided by the invention is green and environmental friendly, has high yield, and can prepare donepezil hydrochloride with high purity, thus being suitable for industrial production.
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Paragraph 0035; 0041; 0042
(2016/10/09)
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- Hydroxylation versus Halogenation of Aliphatic C?H Bonds by a Dioxygen-Derived Iron–Oxygen Oxidant: Functional Mimicking of Iron Halogenases
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An iron–oxygen intermediate species generated in situ in the reductive activation of dioxygen by an iron(II)–benzilate complex of a monoanionic facial N3ligand, promoted the halogenation of aliphatic C?H bonds in the presence of a protic acid and a halide anion. An electrophilic iron(IV)–oxo oxidant with a coordinated halide is proposed as the active oxidant. The halogenation reaction with dioxygen and the iron complex mimics the activity of non-heme iron halogenases.
- Chatterjee, Sayanti,Paine, Tapan Kanti
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supporting information
p. 7717 - 7722
(2016/07/07)
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- Modeling Non-Heme Iron Halogenases: High-Spin Oxoiron(IV)-Halide Complexes That Halogenate C-H Bonds
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The non-heme iron halogenases CytC3 and SyrB2 catalyze C-H bond halogenation in the biosynthesis of some natural products via S = 2 oxoiron(IV)-halide intermediates. These oxidants abstract a hydrogen atom from a substrate C-H bond to generate an alkyl radical that reacts with the bound halide to form a C-X bond chemoselectively. The origin of this selectivity has been explored in biological systems but has not yet been investigated with synthetic models. Here we report the characterization of S = 2 [FeIV(O)(TQA)(Cl/Br)]+ (TQA = tris(quinolyl-2-methyl)amine) complexes that can preferentially halogenate cyclohexane. These are the first synthetic oxoiron(IV)-halide complexes that serve as spectroscopic and functional models for the halogenase intermediates. Interestingly, the nascent substrate radicals generated by these synthetic complexes are not as short-lived as those obtained from heme-based oxidants and can be intercepted by O2 to prevent halogenation, supporting an emerging notion that rapid rebound may not necessarily occur in non-heme oxoiron(IV) oxidations.
- Puri, Mayank,Biswas, Achintesh N.,Fan, Ruixi,Guo, Yisong,Que, Lawrence
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p. 2484 - 2487
(2016/03/12)
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- The synthesis of 3-sulfenylflavones via FeCl3-promoted regioselective cyclization of alkynyl aryl ketones with N-arylthiobenzamides
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A FeCl3-promoted regioselective cyclization of alkynyl aryl ketones with N-arylthiobenzamides had been developed for the synthesis of 3-sulfenylflavones derivatives. Various alkynyl aryl ketones and N-arylthiobenzamides with a number of functional groups were compatible in this reaction to afford the corresponding 3-sulfenylflavones in moderate to good yields. The mechanism was described in detail.
- Shi, Lin-Feng,Zhang, Xing-Guo,Zhang, Xiao-Hong
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supporting information
p. 8617 - 8622
(2016/12/07)
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- Efficient and mild swern oxidation using a new sulfoxide and bis(trichloromethyl)carbonate
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A new type of sulfoxide, 4-(2-(2-(methylsulfinyl) ethyl)-4-nitrophenyl)-morpholine (I), was designed and prepared in good yield. Upon the combination of I and bis(trichloromethyl)carbonate, the Swern oxidation of primary and secondary alcohols was significantly promoted under mild conditions, which afforded the corresponding aldehydes or ketones in good yields. It is noteworthy that the reoxidation of the isolated by-product sulfide V could be further recycled in Swern oxidation.
- Ye, Xiaojing,Fu, Hongliang,Ma, Jiahao,Zhong, Weihui
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p. 885 - 892
(2017/01/28)
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- One-Pot Intermolecular C–S Self-Coupling of Dimethyl Sulfoxide Promoted by Molybdenum Pentachloride
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The reactions between MoCl5and 1–2 equiv. of a selection of sulfoxides at room temperature in dichloromethane as solvent were studied. The 1:1 molar reaction between MoCl5and dimethyl sulfoxide (DMSO) afforded the C–S coupling product [Me2SCH2SMe][MoOCl4] (1), which was isolated in 46 % yield and characterized by analytical and spectroscopic methods and by X-ray diffraction. MoOCl3, SMe2and HCl were identified as side products. The reactions between MoCl5and tetrahydrothiophene 1-oxide, nBu2SO, MePhSO or (PhCH2)2SO yielded the corresponding sulfides and, in the cases of (PhCH2)2SO and MePhSO, also C–S activation compounds. According to DFT calculations, the unusual formation of 1 is the consequence of thermodynamically feasible Cl/O interchange between MoCl5and DMSO, this being a prerequisite for successive C–H bond activation.
- Bortoluzzi, Marco,Ferretti, Eleonora,Hayatifar, Mohammad,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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p. 3838 - 3845
(2016/08/19)
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- Investigation into the stability and reactivity of the pentacyclic alkaloid dehydroevodiamine and the benz-analog thereof
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Limited synthetic approaches to obtain the biologically active alkaloid dehydroevodiamine (DHED) are known to date. Undesired demethylation in the most widely applied route was found to be a hampering side reaction for the benz-DHED derivative leading to a quinazolinone, which represents a benz-rutaecarpine derivative. For rutaecarpine, a related plant alkaloid, many different synthetic approaches have been described. Alternative reaction procedures to obtain DHED such as methylation of rutaecarpine and oxidation of evodiamine were investigated to make DHED more easily accessible and the latter method proved to be the most successful one. Furthermore, the remarkable equilibrium between the ring closed quinazolinium and the ring open form of the compounds was systematically investigated by UV-vis measurements. The ring open form and the quinazolinium salt, form the same species when incubated in buffer solution for 24 h. A better soluble form, i.e., 'hydroxyevodiamine', seems to represent the biologically active form that has not yet been described.
- Wehle, Sarah,Espargaró, Alba,Sabaté, Raimon,Decker, Michael
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p. 2535 - 2543
(2016/04/26)
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- A Visible-Light-Induced α-H Chlorination of Alkylarenes with Inorganic Chloride under NanoAg@AgCl
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An efficient, photocatalytic chlorination of alkylarene α-H groups using NaCl/HCl as a chlorine source has been developed, which involves a radical mechanism under visible-light (including sunlight) conditions. A chlorine radical is proposed to be formed by an electron transfer from chloride ion to O2 in air through the bandgap hole of the semiconductor AgCl. The chlorination protocol is characterized by its use of natural sunlight or other visible light, mild conditions, cheap source of chlorine, green solvent, and high selectivity. The yield of benzylchloride is 95 % with a toluene conversion as high as 40 %, which rivals traditional chlorination methods.
- Liu, Shouxin,Zhang, Qi,Li, Huiying,Yang, Yihua,Tian, Xia,Whiting, Andrew
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supporting information
p. 9671 - 9675
(2015/06/30)
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- Iron catalyzed halogenation of benzylic aldehydes and ketones
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A simple and efficient iron-catalyzed method for chlorination of aromatic carbonyl compounds is reported. By using 4-10 mol% Fe(iii) oxo acetate catalyst, prepared by solid state atmospheric oxidation of Fe(ii) acetate, in combination with triethylsilane and chlorotrimethylsilane, hydrosilylation of benzylic carbonyl compounds with subsequent chlorination is achieved within a few hours at room temperature. This new method is mild and rapid compared to the conventional two step approach involving reduction and chlorination reactions in separate stages. Development of synthetic methodology is also supplemented here by kinetic investigation of the reaction mechanism, which supports the tentative mechanisms suggested previously for similar reactions. This journal is
- Savela, Risto,W?rn?, Johan,Murzin, Dmitry Yu.,Leino, Reko
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p. 2406 - 2417
(2015/04/14)
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- Method of manufacturing imidoyl diazidosulfochloride compd. various compd. and manufacturing method of using the same
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PROBLEM TO BE SOLVED: To provide a new production method for synthesizing an imidoyl chloride compound dispensing with chlorination agents having poor handleability, to provide a method for producing various compounds in high yield and purity by using the imidoyl chloride compound, and to provide a method for isolating the imidoyl chloride compound in high efficiency and purity from a mixture of the imidoyl chloride compound and a phthalic anhydride compound.SOLUTION: The method for producing the imidoyl chloride compound comprises reaction of a specific amide compound with a specific phthaloyl chloride compound to produce a specific imidoyl chloride compound.
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Paragraph 0039
(2016/12/16)
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