- Synthesis of allyl esters of fatty acids and their ovicidal effect on Cydia pomonella (L.)
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Eight allyl esters of fatty acids were synthesized in moderate to high yields with a novel two-step procedure using glycerol as a starting material. The two-step methodology avoids the use of allyl alcohol. The first step consisted of heating at 80 °C for 48 h a 2:1:5 mmol mixture of glycerol, a fatty acid, and chlorotrimethylsilane in a solvent-free medium. The crude compound was then dissolved in butanone and heated at 115 °C in the presence of Nal. A tandem Finkelstein rearrangement-elimination reaction occurs, producing the corresponding allyl ester. The activity of these esters against Cydia pomonella (L.) (Lepidoptera: Tortricidae) eggs was tested in the laboratory by topical application of one 0.1 μL drop. All of the compounds showed a concentration-mortality response and caused 100% mortality at the highest concentration tested (10 mg/mL). There was an inverse relationship between the alkyl chain length and the ovicidal activity of the allyl ester; the LC50 and the LC90 of the two compounds that have the longer alkyl chains were significantly higher than those of the rest of the compounds. The ovicidal and IGR activities of this kind of compound appear to be unprecedented.
- Escriba, Marc,Barbut, Montserrat,Eras, Jordi,Canela, Ramon,Avilla, Jesus,Balcells, Merge
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- An efficient iron catalyzed regioselective acylative cleavage of ethers: Scope and mechanism
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A method involving iron catalyzed acylative cleavage of cyclic and acyclic ethers with acyl/aroyl chlorides has been studied to produce chloroesters and esters respectively. Examination of the scope revealed that less electron rich alkyl group in unsymmetric, acyclic ether was acylated while the chloride derived from the counterpart moiety was volatile and difficult to isolate. In contrast, α-branched cyclic ethers were converted to the corresponding primary ester and secondary chloride. Steric hindrance of ether also plays an important role in acylative C-O bond cleavage. The mechanism of ether cleavage is proposed to involve a single electron initiated SN1 dissociative pathway.
- Bodduri, V.D. Vijaykumar,Choi, Kyung-Min,Vaidya, Raghavender Rao,Patil, Kalpesh,Chirumarry, Sridhar,Jang, Kiwan,Yoon, Yong-Jin,Falck, John R.,Shin, Dong-Soo
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supporting information
p. 7089 - 7093
(2015/12/01)
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- Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols
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(Chemical Equation Presented) A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO4-SiO2). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C10) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H2SO4, HBr, TfOH, HBF4, and TFA that were adsorbed on silica gel were less effective compared to HClO4-SiO2 following the order HClO4-SiO 2 ? H2SO4-SiO2 > HBr-SiO 2 > TfOH-SiO2 ? HBF4-SiO2 ≈ TFA-SiO2. When HClO4 was immobilized on other solid supports the catalytic efficiency followed the order HClO4-SiO 2 > HClO4-K10 > HClO4-Al 2O3 (neutral) > HClO4-Al2O 3 (acidic) > HClO4-Al2O3 (basic).
- Chakraborti, Asit K.,Singh, Bavneet,Chankeshwara, Sunay V.,Patel, Alpesh R.
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supporting information; experimental part
p. 5967 - 5974
(2009/12/24)
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- Practical preparation of esters and thioacetates from alkyl halides and carboxylates or thioacetate catalyzed by PEG400 without solvent
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Carboxylic esters and thioacetates were conveniently prepared in good to excellent yields under mild conditions by the reaction of alkyl halides with sodium carboxylates or sodium thioacetate catalyzed by PEG400 in the absence of solvents. Copyright Taylor & Francis Group, LLC.
- Cao, Yu-Qing,Wu, Guo-Qiang,Li, Ya-Bin,Dai, Zhi,Chen, Bao-Hua
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p. 3353 - 3358
(2007/10/03)
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- Group 5 and group 6 metal halides as very efficient catalysts for acylative cleavage of ethers
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Group 5 and 6 metal chlorides such as MoCl5, WCl6, NbCl5 and TaCl5 were found as very efficient catalysts for acylative cleavage of the C-O bond of ethers. Compared with conventional Lewis acid catalysts such as ZnCl2, AlCl3, SnCl4 and TiCl4, group 5 and 6 metal chlorides showed better results in the catalytic C-O bond cleavage of dibutyl ether with benzoyl chloride.
- Guo, Qiaoxia,Miyaji, Taichi,Hara, Ryuichiro,Shen, Baojian,Takahashi, Tamotsu
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p. 7327 - 7334
(2007/10/03)
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- Catalytic C-O bond cleavage of ethers using group 5 or 6 metal halide/acid chloride systems
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Ethers reacted with acid chlorides in the presence of a catalytic amount of MCl5/6 (M = Mo, W, Nb or Ta) to give esters in 75-98% yield; a stoichiometric reaction of dioctyl ether with MoCl5 afforded 1-chlorooctane in 93% yield and addition of benzoyl chloride to the resulting mixture gave octyl benzoate in 49% yield.
- Guo,Miyaji,Gao,Hara,Takahashi
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p. 1018 - 1019
(2007/10/03)
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- An improved method for preparation of carboxylic esters using CsF- celite/alkyl halide/CH3CN combination
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A new method for efficient and chemoselective esterification of carboxylic acids in CsF-Celite/alkyl halide/CH3CN reaction system is described.
- Lee, Jong Chan,Choi, Youngsup
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p. 2021 - 2026
(2007/10/03)
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- Microwave irradiation promoted reactions of carboxylic acids with halides in the presence of quarternary ammonium salt
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The reactions of carboxylic acids with halides which could not take place by conventional heating are promoted by microwave irradiation in the presence of quaternary ammonium salt as a catalyst, without a base.
- Yuan,Jiang,Gao
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p. 3109 - 3114
(2007/10/02)
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- Palladium-Catalyzed Decarboxylation-Allylation of Allylic Esters of α-Substituted β-Keto Carboxylic, Malonic, Cyanoacetic, and Nitroacetic Acids
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Decarboxylation-allylation of allylic β-keto carboxylates using Pd(OAc)2-PPh3 or Pd2(dba)3*CHCl3-dppe as a catalyst proceeds smoothly to give α-allylated ketones.The reaction is highly regioselective.In some cases, diallylated ketones are obtained with allylic esters bearing an active proton(s).Also rhodium, molybdenum, and nickel complexes sre active catalysts in this reaction.Similarly allylic esters of α-substituted malonates, cyanoacetates, and nitroacetate undergo the palladium-catalyzed decarboxylation-allylation to afford allylated acetate, acetonitrile, and nitromethane, respectively.The mechanisms of these palladium-cataly zed decarboxylation-allylations are discussed
- Tsuji, Jiro,,Yamada, Toshiro,Minami, Ichiro,Yuhara, Masami,Nisar, Mohammad,Shimizu, Isao
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p. 2988 - 2995
(2007/10/02)
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