- Influence of Spacer Chains and Percentage Ring Substitution on Phase-transfer Catalytic Activity of Phosphonium Salts Bonded to Polystyrene Matrix
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In nucleophilic aliphatic substitutions carried out under liquid-liquid phase-transfer conditions, the catalytic activity of tributylphosphonium groups directly bonded to a polystyrene matrix through a methylene bridge decreases by about one order of magnitude on passing from 10 to 69percent ring substitution; log kobs. is linearly related to the loading of the catalytic sites.When tributylphosphonium groups are bonded to the polymer matrix by a linear spacer chain of 13 atoms for 10-30percent ring substitution, kobs. increases 1.7-3.1 times with respect to directly bonded catalysts.However, for spaced catalysts with 60percent ring substitution, the observed rate increase is 4.1-10-fold.This behaviour is explained by the combination of two opposing effects: (i) a polarity increase at the catalytic site by increasing percentage ring substitution leading to a decrease of nucleophilic activity of the anions; (ii)a polarity decrease at the catalytic site by insertion of spacer chains, due to the intrinsic lipophilicity of the alkyl chains as well as the more even distribution of catalytic sites within the polymer matrix.The reactivities of the catalysts, all prepared from chloromethylated polystyrene (200-400 mesh), are independent of the size of particles separated by sieves.
- Anelli, Pier Lucio,Montanari, Fernando,Quici, Silvio
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- Syntheses of long-chain quaternary ammonium salts from fatty alcohols by microwave irradiation
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The phase-transfer catalysts, long-chain quaternary ammonium salts, were rapidly synthesized from fatty alcohols by the reactions with hydrogen halides in the presence of trialkyl amines under microwave irradiation. The catalysts could be widely applied in a variety of quick and new organic reactions, whether by conventional heating or under microwave irradiation. The reaction efficiencies under microwave irradiation were higher than those obtained with conventional heating.
- Jiang,Hu,Pang,Yuan
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- Silicon polypodands: A new class of efficient solid-liquid phase-transfer catalysts
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Silicon polypodands 1-7 were found to be powerful complexing agents of alkali metal salts, even in low polarity media (chlorobenzene) and hence very efficient phase-transfer catalysts. Their catalytic activity was measured in typical anion-promoted reactions under solid-liquid phase-transfer catalysis (SL-PTC) conditions. It is mainly determined by the complexing ability of the ligand, increasing with the number of silicon atoms and binding sites. Comparison with traditional phase-transfer catalysts showed that these polypodands are better catalysts not only than open-chain PEG400Me2 and TRIDENT, but even than more sophisticated macrocyclic polyethers such as DCH18C6.
- Maia, Angelamaria,Landini, Dario,Leska, Boguslawa,Schroeder, Grzegorz
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- Novel Synthesis of Long-Chain Primary Alkyl Compounds
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A method has been developed for the efficient laboratory-scale synthesis of long-chain compounds involving the metathesis of α-olefins to long-chain internal olefins, followed by hydrozirconation.The latter process gives the terminally substituted zirconium alkyl exclusively, which can be converted to a wide variety of functional groups.This paper deals exclusively with the formation of long-chain primary iodides.
- Gibson, Thomas,Tulich, Linda
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- On the behaviour of sulfonates towards As(III) nucleophiles
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Mesylates and hydrophilic amsylates and [3]betylates were tried as substrates in an effort to create a C-As bond. In no case did we detect the formation of arsonic acids. With Na3AsO3 as nucleophile the product was the parent alcohol due to exclusive attack of the HO- present in the aqueous Na3AsO3. With (PhS)3As as the nucleophile in the absence of Lewis acid catalyst the products were diphenyl disulfide and AS2O3 while in the presence of catalyst alkyl phenyl sulfide was obtained, implying that the electron pair on As was chemically inactive. As2O3 did not react with these electrophiles, and potassium di-O-phenylenedioxyarsenate(III) was unreactive towards alkyl bromides but it gave the monoalkyl ether of catechol with amsylates and [3]betylates, again implying that the stereochemically active electron pair of As was not chemically active.
- Tsivgoulis, Gerasimos M.,Sotiropoulos, Demetrios N.,Ioannou, Panayiotis V.
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- Phase-Transfer Reactions Catalyzed by Lipophilic Cryptands and Dicyclohexano-18-crown-6: Dehydrating Effect of Concentrated Aqueous Alkaline Solutions
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A study of how the concentration of aqueous KOH affects the hydration and hence the reactivity of anions (Cl-, Br-, I-, SCN-, N3-) in aliphatic nucleophilic substitutions catalyzed by lipophilic cryptand (1a) and dicyclohexano-18-crown-6 (DCH18C6) (2) under phase-transfer conditions is reported.A comparison with the same reactions performed in classical liquid-liquid PTC and homogeneous anhydrous conditions is also included.Unlike quaternary onium salts, even at the highest KOH concentrations (53percent; ie., conditions in which aH2O ca. 0), water in the presence of 1a is not completely removed.Residual hydration depends on the nature of the anion and is the highest for anions with localized and/or less polarizable charge, such as Cl-, Br-, and N3-.As a consequence, rate constants noticeably increase in comparison with those found under conventional PTC conditions but do not reach those of anhydrous solutions.The different behavior of cryptates and quaternary salts is discussed on the basis of the different topology of the two systems.Behavior of crown ethers is in between that of quaternary salts and cryptates, since residual hydration in the presence of 53percent aqueous KOH is lower than that of cryptates, whereas anionic reactivity becomes practically identical with that found under anhydrous conditions.
- Landini, Dario,Maia, Angelamaria,Montanari, Fernando
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- Bromide-Chloride Exchange between Alkyl Halides and Metal Halide Salts under Phase Transfer Conditions
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The equilibrium position of the phase transfer catalysed exchange reaction RCl + MBr -->/-- RBr + MCl where R = primary alkyl group and M = Li, Na, K, Ca is strongly dependent on the nature of the metal cation M and the amount of water present in the reaction mixture; this has been applied in the synthetic use of the reaction in both directions.
- Sasson, Y.,Weiss, M.,Loupy, A.,Bram, G.,Pardo, C.
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- Synthesis of isoprenoid chain-contained chemical probes for an investigation of molecular interactions by using quartz crystal microbalance
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Five probes including four that contained isoprenoid chain were synthesized. These probes were assembled onto the gold-coated quartz crystal chips for analysis of their interactions with four yeast proteins by using the quartz crystal microbalance technology. Results showed that 3-phosphoglycerate phosphokinase and triosephosphate isomerase had clear interactions with certain probes, while glutathione reductase and phosphoglucose isomerase gave much lower interaction signals. It also suggested that 3-phosphoglycerate phosphokinase had two sites interacting with the probe attached with a geranyl moiety. Further molecule simulation experiments provided supportive information on these intermolecular interactions. Together, our data suggested that there are hydrophobic interactions, with relatively good selectivity, between isoprenoid chain and proteins.
- Liu, Wujun,Zhang, Yixin,Hou, Shuhua,Zhao, Zongbao Kent
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- The catalytic activity of ionophoric calix[4]arene analog
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Calix[4]arene analog (2) having 2-[2-(2-methoxyethoxy)ethoxy]ethyl groups was prepared in 92% yield. Compound 2 showed the extraction of alkali metal ions as an ionophore and the catalytic activity for some S(N)2 reactions.
- Okada,Sugitani,Kasai,Nishimura
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- Crown ethers as phase-transfer catalysts. A comparison of an ionic activation in aqueous-organic two-phase systems and in low polarity anhydrous solutions by perhydrodibenzo-18-crown-6, lipophilic quaternary salts, cryptands
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Anion-promoted nucleophilic substitutions carried out in aqueous-organic two-phase systems in the presence of catalytic amounts of perhydrodibenzo-18- crown-6 follow the classic mechanism of phase-transfer catalysis. The observed pseudo-first-order rate constants are linearly related to the concentration of complexed crown ether in the organic phase. The narrow reactivity range and the sequence found in the reaction between n-octyl methane-sulphonate and a homogeneous series of anions in the PhCl-H2O two-phase system (N 3- > I- ~ Br- > CN - > Cl- > SCN-) remain largely unaltered in anhydrous PhCl. From this point of view complexed crown ethers differ substantially from lipophilic quaternary salts and cryptates. Indeed, removal of the hydration sphere of the anions in going from two-phase to anhydrous conditions is balanced by a larger cation-anion interaction, resulting in a very small variation of anion reactivity. This indicates that, unlike cryptates, complexed crown ethers can hardly be considered as a source of 'naked anions.' A comparison is also reported among lipophilic crown ethers, quaternary salts, and cryptands as phase-transfer catalysts.
- Landini, Dario,Maia, Angelamaria,Montanari, Fernando,Pirisi, Filippo M.
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- MOLECULAR MECHANISM OF HYDROGEN BROMIDE ADDITION TO OLEFINS
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Experimental results on the products and the kinetics of the hydrogen bromide addition to alkenes-1 in non-polar solvents and on complex formation in hydrogen bromide-olefin-solvent systems are reviewed.Theoretical calculations concerning hydrogen bromide-olefin complexes are used along with the experimental evidence to suggest a molecular mechanism of addition involving intermediate cyclic structures.
- Sergeev, G. B.,Stepanov, N. F.,Leenson, I. A.,Smirnov, V. V.,Pupyshev, V. I.,et al.
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- Functionalized Ethylene Oligomers as Phase-Transfer Catalysts
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Ethylene oligomers with Mv in the range 1000-3000 containing terminal groups such as crown ethers, azacrown ethers, and phosphonium salts have been prepared and used as phase-transfer catalysts.These oligomeric catalysts have solubility properties similar to polyethylene in that they are insoluble at 25 deg C but dissolve in organic solutions at elevated (90-110 deg C) temperatures.Such oligomeric phase-transfer catalysts have activities comparable to their low molecular wait congeners and to activities reported for insoluble polystyrene-bound phase-transfer catalysts.After these oligomeric catalysts have been used in a reaction at 100 deg C, thay can be readily separated from the reaction products by cooling to form a precipitate, which can be isolated by filtration.Such catalysts may be reused without loss of activity.These catalysts are also effective in "solid-liquid" phase-transfer reactions in which an inorganic solid is suspended in a hot organic solution containing catalyst and substrate.
- Bergbreiter, David E.,Blanton, J. R.
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- Nonhydrated Anion Transfer from the Aqueous to the Organic Phase: Enhancement of Nucleophilic Reactivity in Phase-Transfer Catalysis
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A systematic study of how the nature and concentration of the inorganic salt affect hydration and reactivity of anions transferred into the organic phase under conditions of phase-transfer catalysis (PTC) has been performed.The inorganic salt concentration in the aqueous phase up to saturated solution (= or > 6 M), does not affect the hydration and hence the reactivity of the anion in aliphatic nucleophilic substitutions.On the other hand, in concentrated aqueous alkaline solutions (50percent NaOH or 60percent KOH) unhydrated anions are transferred from the aqueous to the organic phase.The anionic reactivity thus becomes identical with that found under anhydrous homogeneous conditions, the rate enhancement being 13.0, 4.0, 2.6, and 1.4 times for Cl(1-), N3(1-), Br(1-), and I(1-), respectively.The same dehydrating effect was not observed with less concentrated alkaline solutions or with 50percent aqueous NaF.These data show the unique property of OH(1-) in producing conditions of virtually null water activity under PTC conditions.
- Landini, Dario,Maia, Angelamaria,Podda, Gianni
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- Synthesis of 1-bromooctane catalyzed by solid super acid SO 42-/ZrO2-ZnO
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The solid super acid catalyst SO42-/ZrO 2-ZnO was prepared by impregnation and characterized by infrared spectroscopy, X-ray diffraction, different scanning calorimetric and thermogravimetric analysis. Their performances were evaluated by the synthesis of 1-bromooctane. Under the condition of n-octanol/hydrobromic acid molar ratio of 1:3, a catalyst amount of 8 wt. %, reaction time of 7 h, temperature of 130 °C, produce 1-bromooctane (yield 70.22 %).
- Hu, Guoqin,Tan, Liuyang,Cui, Leiming,Wu, Peipei
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- A new type of B-podand catalysts for solid-liquid phase transfer reactions
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Boron podands 1-4 (B-podands) were studied as strong complexing agents of alkali metal cations and very powerful catalysts in typical anion promoted reactions under solid-liquid conditions, even in chlorobenzene and acetonitrile. The results were comparable with the catalytic activity of classical phase transfer catalysts: crown ethers, polyethylene glycols (PEG) and previously studied Si-podands.
- ?eska, Bogus?awa,Pankiewicz, Rados?aw,Schroeder, Grzegorz,Maia, Angelamaria
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- Silicon polypodands: Powerful metal cation complexing agents and solid-liquid phase-transfer catalysts of new generation
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Silicon polypodands 5-7 are found to be powerful complexing agents of alkali metal salts in low polarity solvents and very efficient catalysts in anion-promoted reactions under solid-liquid PTC conditions. The catalytic activity is comparable with that of the cyclic polyether PHDB18C6 8.
- Maia, Angelamaria,Landini, Dario,Leska, Boguslawa,Schroeder, Grzegorz
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- A General Approach to Deboronative Radical Chain Reactions with Pinacol Alkylboronic Esters
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The generation of carbon-centered radicals from air-sensitive organoboron compounds through nucleohomolytic substitution at boron is a general method to generate non-functionalized and functionalized radicals. Due to their reduced Lewis acidity, alkylboronic pinacol esters are not suitable substrates. We report their in situ conversion into alkylboronic catechol esters by boron-transesterification with a substoichiometric amount of catechol methyl borate combined with an array of radical chain processes. This simple one-pot radical-chain deboronative method enables the conversion of pinacol boronic esters into iodides, bromides, chlorides, and thioethers. The process is also suitable the formation of nitriles and allylated compounds through C?C bond formation using sulfonyl radical traps. The power of combining radical and classical boron chemistry is illustrated with a modular 5-membered ring formation using a combination of three-component coupling and protodeboronative cyclization.
- André-Joyaux, Emy,Kuzovlev, Andrey,Renaud, Philippe,Tappin, Nicholas D. C.
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p. 13859 - 13864
(2020/06/10)
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- Method for continuously synthesizing bromo-n-octane in micro-reactor
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The invention discloses a method for continuously synthesizing bromo-n-octane in a micro-reactor. According to the method, n-octyl alcohol is used as a raw material, hydrobromic acid is used as a bromination reagent, and concentrated sulfuric acid is used as a catalyst to synthesize 1-bromo-n-octane in a microreactor. Because the width and depth of micro-channels in the reactor are small and rangefrom dozens of microns to hundreds of microns, the diffusion distance among reactants is greatly shortened, the mass transfer speed is high, and the reactants can be fully mixed and reacted in a short time in the flowing process. According to the method, microreactor technology is introduced into synthesis of bromo-n-octane, n-octyl alcohol is used as an initial raw material, hydrobromic acid isused as a bromination reagent, and concentrated sulfuric acid is used as a catalyst, so that continuous preparation of 1-bromo-n-octane is realized, the reaction operation is simple, the selectivity and yield of the product are relatively high, and the method has a wide industrial development prospect.
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Paragraph 0017-0037
(2020/01/14)
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- Synthesis of Branched Biolubricant Base Oil from Oleic Acid
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The mature manufacturing of synthetic lubricants (poly-α-olefins, PAO) proceeds through oligomerization, polymerization, and hydrogenation reactions of petrochemical ethylene. In this work, we utilize the inexpensive bio-derived oleic acid as raw material to synthesize a crotch-type C45 biolubricant base oil via a full-carbon chain synthesis without carbon loss. It contains several cascade chemical processes: oxidation of oleic acid to azelaic acid (further esterification to dimethyl azelate) and nonanoic acid (both C9 chains). The latter is then selectively hydrogenated to nonanol and brominated to the bromo-Grignard reagent. In a next step, a C45 biolubricant base oil is formed by nucleophilic addition (NPA) of excessive C9 bromo-Grignard reagent with dimethyl azelate, followed by subsequent hydrodeoxygenation. The specific properties of the prepared biolubricant base oil are almost equivalent to those of the commercial lubricant PAO6 (ExxonMobil). This process provides a new promising route for the production of value-added biolubricant base oils.
- Chen, Shuang,Wu, Tingting,Zhao, Chen
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p. 5516 - 5522
(2020/09/07)
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- Promotion of Appel-type reactions by N-heterocyclic carbenes
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N-Heterocyclic carbenes (NHCs) have been extensively used as a versatile class of catalysts and ligands in organocatalytic and organometallic chemistry. However, there are only a small number of synthetic applications where they act as reagents. Here we demonstrate that NHCs can be used as stoichiometric redox reagents for Appel-type halogenation reactions of alcohols. This new reactivity reveals a fresh and interesting aspect and enriches the chemistry of NHCs in an underexplored area. The potential of performing this chemical transformation at the catalytic level using an NHC-oxide derivative is also investigated.
- Hussein, Mohanad A.,Nguyen, Thanh Vinh
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supporting information
p. 7962 - 7965
(2019/07/12)
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- An efficient conversion of alcohols to alkyl bromides using pyridinium based ionic liquids: A green alternative to appel reaction
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Pyridinium based ionic liquids namely 4-alkylpyridinium bromides were prepared and used for the conversion of alcohols to alkyl bromides in the presence of p-toluenesulphonic acid in the absence of volatile organic compounds. This solvent free procedure promises to be a much improved and environmentally benign alternative to the Appel reaction.
- Das, Pranab J.,Das, Jupitara,Das, Dimpee
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p. 651 - 654
(2018/02/09)
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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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- Preparation method of alpha-bromo-n-octane
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The invention discloses a preparation method of alpha-bromo-n-octane. The alpha-bromo-n-octane is prepared by taking 1-octene as a raw material and benzoperoxide as an initiating agent without a solvent, strictly controlling the reaction temperature and the flow of hydrogen bromide, and performing the processes of reaction, washing, distillation and the like. According to the preparation method disclosed by the invention, the reaction at a normal pressure without the solvent is adopted, the raw material is easy to obtain, the cost is low, the reaction condition is mild, the after-treatment is simple, and a 'temperature runaway' phenomenon during reaction is avoided at the same time.
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Paragraph 0019; 0020
(2016/10/17)
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- Catalytic halodefluorination of aliphatic carbon-fluorine bonds
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A variety of halosilanes, in conjunction with aluminum catalysts, convert fluorocarbons into higher halocarbons. Bromination and iodination of fluorocarbons are more effective than chlorination in terms of yield and activity. The mechanism for the reaction is investigated utilizing experimental and computational evidence and preliminary results suggest an alternate mechanism to that reported for the related hydrodefluorination reaction.
- Goh, Kelvin K.K.,Sinha, Arup,Fraser, Craig,Young, Rowan D.
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p. 42708 - 42712
(2016/05/19)
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- C-substituted, 1H-azoles for amphoteric, solvent-less proton conductivity
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Disclosed herein are the compounds shown below. Also disclosed are methods of making the compounds. R1=—O—; R2=any alkyl chain; R3=—CH3, —CN, —COOCH3, -tetrazole, -imidazole, or -triazole; R4=—H or —R5; R5=—H, -halogen, —C≡CH, or —C≡C—; n is a positive integer; and m is a positive integer.
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- Reaction of α-carbanions of lithium acylates with 1,2-dibromoethane
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The reaction of 1,2-dibromoethane with α-carbanions of lithium acylates generated from acetic, butyric, isobutyric, and capronic acids with lithium diisopropylamide has been studied. Anion-radical and anionic pathways of the products formation have been discussed.
- Zorin,Zaynashev,Chanysheva,Zorin
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p. 1382 - 1385
(2015/08/03)
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- Halogen Exchange Reaction of Aliphatic Fluorine Compounds with Organic Halides as Halogen Source
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The halogen exchange reaction of aliphatic fluorine compounds with organic halides as the halogen source was achieved. Treatment of alkyl fluorides (primary, secondary, or tertiary fluorides) with a catalytic amount of titanocene dihalides, trialkyl aluminum, and polyhalomethanes (chloro or bromo methanes) as the halogen source gave the corresponding alkyl halides in excellent yields under mild conditions. In the case of a fluorine/iodine exchange, no titanocene catalyst is needed. Only C-F bonds are selectively activated under these conditions, whereas alkyl chlorides, bromides, and iodides are tolerant to these reactions.
- Mizukami, Yuki,Song, Zhiyi,Takahashi, Tamotsu
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supporting information
p. 5942 - 5945
(2016/01/09)
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- Tribromoisocyanuric acid/triphenylphosphine: A new system for conversion of alcohols into alkyl bromides
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An efficient and facile method has been developed for the conversion of alcohols into alkyl bromides under neutral conditions using tribromoisocyanuric acid and triphenylphosphine (molar ratio 1.0:0.7:2.0, alcohol/ tribromoisocyanuric acid/triphenylphosphine) in dichloromethane at room temperature. This method can be applied for the conversion of primary, secondary, benzylic and allylic alcohols, and their corresponding bromides are obtained in 67-82 percent yield. Tertiary alcohols do not react under these conditions.
- De Andrade, Vitor S.C.,De Mattos, Marcio C.S.
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p. 975 - 979
(2014/06/24)
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- C-SUBSTITUTED, 1H-AZOLES FOR AMPHOTERIC, SOLVENT-LESS PROTON CONDUCTIVITY
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Disclosed herein are the compounds shown below. Also disclosed are methods of making the compounds. R1=—O—; R2=any alkyl chain; R3=—CH3, —CN, —COOCH3, -tetrazole, -imidazole, or -triazole; R4=—H or —R5; R5=—H, -halogen, —C≡CH, or —C≡C—; n is a positive integer; and m is a positive integer.
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Page/Page column
(2014/02/16)
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- Synthesis of silica bromide as heterogeneous reagent and its application to conversion of alcohols to alkyl bromides
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Silica bromide as heterogeneous reagent is prepared from the reaction of silica gel with PBr3 as a nonhydroscopic, filterable, cheap, and stable yellowish powder that can be stored for months. The results show that the silica bromide is a suitable and efficient reagent for conversion of alcohols to alkyl bromides under mild conditions at room temperature. The easy availability of this reagent makes this simple procedure attractive and a practical alternative to the existing methods.
- Mohanazadeh, Farajollah,Sedrpoushan, Alireza,Zolfigol, Mohammad A.,Veisi, Hojat
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p. 598 - 603,6
(2012/12/11)
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- A facile and green protocol for nucleophilic substitution reactions of sulfonate esters by recyclable ionic liquids [bmim][X]
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Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X-) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process greener.
- Liu, Yajun,Xu, Yongnan,Jung, Sun Ho,Chae, Junghyun
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p. 2692 - 2698,7
(2012/12/12)
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- A facile and green protocol for nucleophilic substitution reactions of sulfonate esters by recyclable ionic liquids [bmim][X]
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Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X-) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process greener. Georg Thieme Verlag KG Stuttgart · New York.
- Liu, Yajun,Xu, Yongnan,Jung, Sun Ho,Chae, Junghyun
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p. 2692 - 2698
(2013/01/15)
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- Differentiating C-Br and C-Cl bond activation by using solvent polarity: Applications to orthogonal alkyl-alkyl negishi reactions
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A pot to share: A Calkyl-Cl bond can be rendered "dormant" or "active" in the Negishi alkyl-alkyl cross-coupling by a simple solvent polarity "switch" (see scheme). Adjustment from a 1:2 to a 2:1 solvent ratio of dimethylimidazolidinone: tetrahydrofuran enables orthogonal alkyl-alkyl Negishi cross-coupling strategies to be carried out on bifunctional bromochloroalkanes in one pot at room temperature.
- Hadei, Niloufar,Achonduh, George T.,Valente, Cory,O'Brien, Christopher J.,Organ, Michael G.
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supporting information; experimental part
p. 3896 - 3899
(2011/06/24)
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- H3PW12O40-[bmim][FeCl4]: A novel and green catalyst-medium system for microwave-promoted selective interconversion of alkoxymethyl ethers into their corresponding nitriles, bromides and iodides
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In the present work, the catalytic activity of 12-tungstophosphoric acid immobilized on [bmim][FeCl4] ionic liquid as a highly efficient and eco-friendly catalytic system for rapid and chemoselective direct conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides and iodides under microwave irradiation is reported. In these reactions, the products are obtained in high yields. The catalyst exhibited remarkable reactivity and was reused several times.
- Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiolah,Mirjafari, Arsalan
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experimental part
p. 1468 - 1473
(2011/10/09)
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- Microwave-promoted, one-pot conversion of alkoxymethylated protected alcohols into their corresponding nitriles, bromides, and iodides using [bmim][InCl4] as a green catalyst
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The Lewis acid room temperature ionic liquid, [bmim][InCl4], was found to be an efficient and green catalyst for the highly chemoselective and one-pot conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides, and iodides under microwave irradiation. The procedures are simple, rapid, and high yielding. The catalyst exhibited a remarkable reactivity and is reusable.
- Mirjafari, Arsalan,Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza
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supporting information; experimental part
p. 3274 - 3276
(2010/07/18)
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- Iron-catalyzed cross-coupling of alkyl sulfonates with arylzinc reagents
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Iron-catalyzed cross-coupling reactions of primary and secondary alkyl sulfonates with arylzinc reagents proceed smoothly In the presence of excess TMEDA and a concomitant magnesium salt. The arylzinc reagents are prepared from the corresponding aryllithium or magnesium reagents with ZnI2. The In situ formation of alkyl Iodides and consecutive rapid cross-coupling avoids discrete preparation of the unstable secondary alkyl halides and also achieves high product selectivity.
- Ito, Shingo,Fujiwara, Yu-Ichi,Nakamura, Eiichi,Nakamura, Masaharu
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supporting information; experimental part
p. 4306 - 4309
(2009/12/26)
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- Reactivity of anionic nucleophiles in ionic liquids and molecular solvents
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The nucleophilic reactivity of a representative series of anions has been measured in [hmim][ClO4] 3i, [hm2im][ClO4] 3′i, and [hmim][PF6] 3l ILs in the reaction with n-alkyl methanesulfonates and compared with that found in common molecular solvents (MeOH, DMSO, PhCl). The reactivity is found to depend on both the imidazolium cation-anion interaction and the specific solvation by water present in the IL, the water playing the main effect, in particular with hydrophilic anions. Removal of the largest quantity of water remarkably increases the ion pair reactivity in the IL up to rate constant value k comparable with those obtained in DMSO and in low polarity media (PhCl).
- Betti, Cecilia,Landini, Dario,Maia, Angelamaria
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p. 1689 - 1695
(2008/09/18)
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- Hexabromoacetone and ethyl tribromoacetate: a highly efficient reagent for bromination of alcohol
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A new and efficient method for the bromination of alcohols utilizing Br3CCOCBr3/PPh3 and Br3CCO2Et/PPh3 is described. Various alcohols can be converted smoothly into their corresponding alkyl bromides in high yields under mild conditions with short reaction times. Based upon 1H NMR studies using competitive reactions between selected brominating agents and Cl3CCN, Br3CCOCBr3 displays the highest reactivity approximately nine times that of CBr4.
- Tongkate, Pratoomrat,Pluempanupat, Wanchai,Chavasiri, Warinthorn
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p. 1146 - 1148
(2008/09/18)
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- The oxidation of alcohols to aldehydes and ketones with N-bromosuccinimide in polyethylene glycol: An experimental and theoretical study
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Oxidation of aliphatic and aromatic alcohols has been studied by using N-bromosuccinimide (NBS) as oxidant and polyethylene glycol (PEG) as reaction medium under mild reaction conditions. Temperature and solvent effect are studied. Theoretical study is also done with the Gaussian 98 suite of program and the calculation results are in good accordance with the experimental outcome. This system offers a very clean, convenient, environmentally benign method for the oxidation of alcohols. Copyright
- Fan, Ji-Cai,Shang, Zhi-Cai,Liang, Jun,Liu, Xiu-Hong,Liu, Yang
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experimental part
p. 945 - 953
(2009/10/26)
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- Conversion of (sp3)C-F bonds of alkyl fluorides to (sp 3)C-heteroatom (heteroatom = I, SR, SeR, TeR) bonds by the use of magnesium reagents having heteroatom substituents
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A convenient method for conversion of (sp3)C-F bonds to (sp 3)C-Z (Z = I, SR, SeR, TeR) bonds has been developed. The reaction proceeds at room temperature using magnesium salts (Z-MgX). SN2 mechanism for substitiution of primary alkyl fluorides with MgI2 in ether was supported by the inversion of the stereochemistry of the carbon connecting to F. Copyright
- Begum, Shameem Ara,Terao, Jun,Kambe, Nobuaki
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p. 196 - 197
(2008/02/03)
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- A new diphenylphosphinite ionic liquid (IL-OPPh2) as reagent and solvent for highly selective bromination, thiocyanation or isothiocyanation of alcohols and trimethylsilyl and tetrahydropyranyl ethers
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A new diphenylphosphinite ionic liquid (IL-OPPh2) is introduced. This ionic liquid is used as both a reagent and a solvent to convert alcohols and trimethylsilyl and tetrahydropyranyl (THP) ethers into their corresponding alkyl bromides, thiocyanates or isothiocyanates in the presence of Br2 and SCN- at 80 °C. In this ionic liquid, bromination and thiocyanation of alcohols occurs highly selectively in the presence of trimethylsilyl and THP-ethers and also between different classes of alcohols. The use of this ionic liquid allows easy separation of the desired products from the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Azadi, Roya
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p. 5531 - 5534
(2007/10/03)
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- Facile conversion of alcohols into their bromides and iodides by N-bromo and N-iodosaccharins/triphenylphosphine under neutral conditions
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N-Bromo and N-iodosaccharins in the presence of triphenylphosphine convert alcohols into the corresponding bromides and iodides in good to excellent yields at room temperature under neutral conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Ebrahimzadeh, Farzaneh
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p. 1771 - 1775
(2007/10/03)
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- 4-Aminophenyldiphenylphosphinite (APDPP), a new heterogeneous and acid scavenger phosphinite - Conversion of alcohols, trimethylsilyl, and tetrahydropyranyl ethers to alkyl halides with halogens or N-halosuccinimides
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A new heterogeneous phosphinite, 4-aminophenyldiphenylphosphinite (APDPP), is prepared and used for the efficient conversion of alcohols, trimethylsilyl ethers, and tetrahydropyranyl ethers to their corresponding bromides, iodides, and chlorides in the presence of molecular halogens or N-halosuccinimides. The amino group in this phosphinite acts as an acid scavenger and removes the produced acid. A simple filtration easily removes the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Gholinejad, Mohammad
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p. 1006 - 1012
(2007/10/03)
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- Process to convert alkanes into primary alcohols
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This invention provides a process to convert alkanes to primary alcohols of the same carbon number. Carbon numbers of particular interest are C8 to C18. The process comprises the steps of: a) halogenating a linear or branched (or mixture of linear and branched) alkane to produce a mixture of primary mono-haloalkanes, internal mono-haloalkanes, unreacted alkanes, hydrogen halide, and possibly multi-haloalkanes in the presence of a catalyst and/or by heating the reaction mixture; b) separating the hydrogen halide from the mixture and optionally neutralizing it with a metal oxide to produce a partially halogenated metal oxide and/or metal halide which may be regenerated; c) separating the primary mono-haloalkanes from the mixture; d) reacting the separated primary mono-haloalkanes in a reactor with a metal oxide or combination of metal oxides and water to convert the aforesaid primary mono-haloalkane to a mixture of products that contains primary alcohols, unconverted primary mono-haloalkanes, and possibly other reaction products, and a partially halogenated metal oxide and/or metal halide which may be regenerated; e) regenerating the partially halogenated metal oxide and/or metal halide to halogen (such as Cl2) and/or acid and a metal oxide for recycle by reaction with air or oxygen; and f) removing the unreacted primary mono-haloalkane from the reaction mixture and then purifying the primary alcohol.
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Page/Page column 7
(2008/06/13)
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- Process to convert linear alkanes into alpha olefins
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This invention provides for a process to convert branched or linear alkanes to branched or linear alpha olefins (AO) of the same carbon number. The process comprises the steps of: a) halogenating linear alkanes, branched alkanes, or a mixture of linear and branched alkane to produce a mixture containing primary mono-haloalkanes and hydrogen halide; b) separating the hydrogen halide from the mixture and optionally neutralizing it with a metal oxide to produce a partially halogenated metal oxide and/or metal halide which may be regenerated; c) separating the primary mono-haloalkanes from the mixture; d) reacting the separated primary mono-haloalkanes with a metal oxide to produce a mixture of products that contains alpha olefins, unconverted primary mono-haloalkanes, possibly other reaction products, and a partially halogenated metal oxide and/or metal halide which may be regenerated; e) regenerating the partially halogenated metal oxide and/or metal halide to halogen and/or acid and a metal oxide (such as Cl2) for recycle by reaction with air or oxygen ; and f) removing the unreacted primary mono-haloalkane from the reaction mixture and then purifying the alpha olefin.
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Page/Page column 7
(2008/06/13)
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- Anion nucleophilicity in ionic liquids: A comparison with traditional molecular solvents of different polarity
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The nucleophilic reactivity of a homogeneous series of anions (halides, pseudohalides and organic anions) in the ionic liquids [hexmim] [ClO 4] and [hexmim] [PF6] has been measured in their reaction with n-alkyl methanesulfonates, and compared with that found in traditional molecular solvents of different polarity, that is, chlorobenzene, DMSO, and MeOH.
- Landini, Dario,Maia, Angelamaria
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p. 3961 - 3963
(2007/10/03)
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- Nucleophilic displacements in supercritical carbon dioxide under phase-transfer catalysis conditions. 2. Effect of pressure and kinetics
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The nucleophilic displacement on n-octylmesylate (n-C8H17OSO2CH3, 1) with four different anions (I-, Br-, N3-, and SCN-) is investigated under liquid-supercritical phase-transfer catalysis (LSc-PTC) conditions, i.e. in a biphase system of supercritical carbon dioxide (scCO2) and water, in the presence of both silica supported and conventional onium salts. The CO2 pressure greatly affects the concentration of 1 in the sc-phase and plays a major role on its conversion. For example, at 50 °C and with a supported PT-catalyst, the conversion of 1 into n-octyl iodide drops by a factor of 5 as the CO2 pressure is increased from 80 to 150 bar, while in the same pressure range, the solubility of n-octylmesylate in scCO2 shows a 6-fold increase, indicating that the reagent is desorbed from the catalyst. Under LSc-PTC conditions, pseudo-first-order kinetic rate constants, evaluated for the investigated reactions, show that the performance of scCO2 as a PTC solvent and the relative nucleophilicity order of the anions (N3- > I- > Br- > SCN-) are comparable to those of toluene and n-heptane. The behavior of conventional phosphonium salts in the scCO2/H2O biphase system suggests that the reaction may take place either within small droplets of PT-catalyst containing water or in a separate third liquid phase of the PT-catalyst itself.
- Loris, Alessandro,Perosa, Alvise,Selva, Maurizio,Tundo, Pietro
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p. 4046 - 4051
(2007/10/03)
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- Ionic liquids as reagents and solvents in conjunction with microwave heating: Rapid synthesis of alkyl halides from alcohols and nitriles from aryl halides
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We show that using ionic liquids as reagents in conjunction with microwave heating it is possible to prepare primary alkyl halides from the corresponding alcohols rapidly. Using ionic liquids as solvents in conjunction with microwave heating it is possible to prepare aryl nitriles from the corresponding aryl bromides or iodides. The scope and limitations of using microwave-promotion as a tool in these reactions is discussed.
- Leadbeater, Nicholas E.,Torenius, Hanna M.,Tye, Heather
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p. 2253 - 2258
(2007/10/03)
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- Conversion of alcohols to bromides using a fluorous phosphine
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Reaction of alcohols with the fluorous phosphine-carbon tetrabromide complex in toluene or in a two-phase toluene-FC-72 system afforded the corresponding bromides in good yields. The fluorous-phosphine oxide is readily separated by liquid-liquid extraction, providing an alternative to the homogeneous triphenylphosphine-carbon tetrachloride conversion, as well as to the polymer-supported phosphine method. The fluorous phosphine oxide could be reduced and the product reused.
- Desmaris, Laurence,Percina, Nathalie,Cottier, Louis,Sinou, Denis
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p. 7589 - 7591
(2007/10/03)
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- Triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone as a new, selective and neutral system for the facile conversion of alcohols, thiols and selenols to alkyl halides in the presence of halide ions
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A mixture of triphenylphosphine (Ph3P) and 2,3-dichloro-5,6-dicyanobenzoquinone in CH2Cl2 affords a complex which in the presence of R4NX (X=Cl, Br, I) converts alcohols, thiols and selenols into their corresponding alkyl halides in high yields at room temperature. The method is highly selective for the conversion of 1° alcohols in the presence of 2° ones and also 1° and 2° alcohols in the presence of 3° alcohols, thiols, epoxides, trimethylsilyl- and tetrahydropyranyl ethers, 1,3 dithianes, disulfides, and amides.
- Iranpoor,Firouzabadi,Aghapour,Vaez zadeh
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p. 8689 - 8693
(2007/10/03)
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- Single step transformation of PMB ethers to bromides using a CBr4-TPP reagent system
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PMB ethers are efficiently transformed to their corresponding bromides by a CBr4-TPP reagent system with a wide range of other functional groups also present in the substrate.
- Yadav,Mishra, Rajesh Kumar
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p. 5419 - 5422
(2007/10/03)
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- Mild conversion of alcohols to alkyl halides using halide-based ionic liquids at room temperature
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Formula presented Alcohols were efficiently converted to alkyl halides using 1-n-butyl-3-methylylimidazolium halides (ionic liquids) in the presence of Bronsted acids at room temperature. The alkyl halide products were easily isolated from the reaction mixture via simple decantation or extraction, and the 1-n-butyl-3-methylimidazolium cation could be recycled for further uses.
- Ren, Rex X.,Wu, Jeff Xin
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p. 3727 - 3728
(2007/10/03)
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- A facile conversion of thiols to alkyl halides by triphenylphosphine/N-halosuccinimides
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Thiols are efficiently converted to alkyl halides in high to excellent yields when treated with triphenylphosphin/N-halosuccinimide (halogen: Br,Cl, and I) in dichloromethane at room temperature.
- Iranpoor,Firouzabadi,Aghapour
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p. 1176 - 1178
(2007/10/03)
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- Nitrogen-based halogenating agents and process for preparing halogen-containing compounds
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Disclosed are a fluorinating agent represented by the general formula (1): wherein R1to R4are a substituted or unsubstituted, saturated or unsaturated alkyl group or a substituted or unsubstituted aryl group, and can be the same or different; R1and R2or R3and R4can bond to form a ring including a nitrogen atom or a nitrogen atom and other hetero atoms; or R1and R3can bond to form a ring including a nitrogen atom or a nitrogen atom and other hetero atoms, for example: a preparation process of the fluorinating agent and a process for preparing fluorine compounds by reacting various compounds with the fluorinating agent. The invention has also disclosed that the fluorinating agent is very effective for fluorinating oxygen containing functional compounds.
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- Study of activation energy and order of reaction of some liquid crystals
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Liquid crystals of the type p-phenylene-di-p-n-alkoxy benzoate have been prepared. Kissinger isothermal decomposition method has been used for determination of activation energy values of liquid crystals. Kissinger's assessment for shape index of DTA peaks is used to find the order of reaction. There is no direct relationship between the carbon atoms in terminal methylene groups and Ea values. Order of reaction value decreases with increase in heating rate upto carbon atoms 10 in the terminal methylene group but beyond this the order increases or decreases.
- Mundhe
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p. 246 - 249
(2007/10/03)
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- Calamitic organometallic liquid crystals with terminal metal. Syntheses and liquid crystal properties of dicarbonylrhodium(I) β-diketonate complexes
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A series of novel organometallic complexes based on γ-substituted β-diketone ligands with terminal metal Rh(I) have been prepared by reaction of the ligands with [Rh(CO)2(μ-Cl)]2. The mesomorphism of the ligands and complexes has been investigated using DSC and polarizing microscope. It is found that non-mesogenic ligands with n=7, 8, 9, 10, 11 can form liquid crystalline phase by direct coordination to metal. The effect of the terminal carbon number on the mesomorphism has also been discussed.
- Wan, Wen,Guang, Wen-Jie,Zhao, Ke-Qin,Zheng, Wei-Zhong,Zhang, Liang-Fu
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p. 157 - 161
(2007/10/03)
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- Field and Electroantennogram Responses of the Pine Sawfly, Diprion nipponica, to Chiral Synthetic Pheromone Candidates
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(1S, 2R, 6RS)-1,2,6-Trimethyldecyl propionate, a lower homolog of the sex pheromone of known sawflies, strongly attracted Diprion nipponica, a popular species in Japan.
- Tai, Akira,Higashiura, Yasutomo,Kakizaki, Masashi,Naito, Tikahiko,Tanaka, Kazuki,Fujita, Morifumi,Sugimura, Takashi,Hara, Hideho,Hayashi, Naotaka
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p. 607 - 608
(2007/10/03)
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- Esterification of carboxylic acid salts
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Mono- or polycarboxylic acid esters are prepared by reacting a salt of such carboxylic acid with an organic halocompound, e.g., a (cyclo)alkyl, (cyclo)alkenyl, aryl or aralkyl halide, in an aqueous reaction medium, in the presence of a catalytically effective amount of a phase transfer catalyst, for example an onium salt.
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