- Industrial preparation method of 2,4,5-trifluorophenylacetic acid
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The invention relates to the technical field of preparation of chemical drug intermediates, and particularly discloses an industrial preparation method of 2,4,5-trifluorophenylacetic acid. The preparation method comprises the following steps: carrying out a nitration reaction, a fluorination reaction, a hydrogenation reduction reaction, a diazotization reaction, a halogenation reaction, a cyaniding reaction, a thermal decomposition reaction and a hydrolysis reaction on 2,4-dichlorotoluene to prepare the 2,4,5-trifluorophenylacetic acid. The method has the advantages of low preparation cost andhigh product yield.
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Paragraph 0030; 0032; 0053
(2021/03/11)
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- Nucleophilic Substitution of Aliphatic Fluorides via Pseudohalide Intermediates
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A method for aliphatic fluoride functionalization with a variety of nucleophiles has been reported. Carbon–fluoride bond cleavage is thermodynamically driven by the use of silylated pseudohalides TMS-OMs or TMS-NTf2, resulting in the formation of TMS-F and a trapped aliphatic pseudohalide intermediate. The rate of fluoride/pseudohalide exchange and the stability of this intermediate are such that little rearrangement is observed for terminal fluoride positions in linear aliphatic fluorides. The ability to convert organofluoride positions into pseudohalide groups allows facile nucleophilic attack by a wide range of nucleophiles. The late introduction of the nucleophiles also allows for a wide range of functional-group tolerance in the coupling partners. Selective alkyl fluoride mesylation is observed in the presence of other alkyl halides, allowing for orthogonal synthetic strategies.
- Jaiswal, Amit K.,Prasad, Pragati K.,Young, Rowan D.
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p. 6290 - 6294
(2019/04/26)
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- Design and synthesis of a magnetic hierarchical porous organic polymer: A new platform in heterogeneous phase-transfer catalysis
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Recyclable phase transfer catalysts containing magnetic nanoparticles (MNPs) have been known as a major trend towards sustainable catalysts. In this study, a novel class of magnetic porous polymer on the basis of calix[4]resorcinarene was synthesized starting from silica-coated Fe3O4 core-shell nanoparticles. This compound was found as an efficient phase transfer catalyst to the conversion of benzyl halides into benzyl azides and cyanides in good yields. The catalyst could be used at least for five consecutive cycles without appreciable loss in the catalytic activity.
- Mouradzadegun, Arash,Ganjali, Mohammad Reza,Mostafavi, Mahsa Alsadat
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- Crown ether functionalized magnetic hydroxyapatite as eco-friendly microvessel inorganic-organic hybrid nanocatalyst in nucleophilic substitution reactions: an approach to benzyl thiocyanate, cyanide, azide and acetate derivatives
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In this paper, high catalytic activity of 4′,4″-diformyl dibenzo-18-crown-6 anchored onto the functionalized magnetite hydroxyapatite (γ-Fe2O3@HAp–Crown) as a new, versatile and magnetically recoverable catalyst, was prepared. It evaluated as phase-transfer catalyst and molecular host system for nucleophilic substitution reactions of benzyl halides with thiocyanate, cyanide, azide and acetate anions in water. No evidence for the formation of by-products was observed and the products obtained in pure form without further purification. The nanocomposite was easily removed from solution via application of a magnetic field, allowing straightforward recovery and reuse. The synthesized nanocomposite was characterized by several techniques such as FT-IR, TGA-DTG, EDX, XRD, BET, FE-SEM, TEM and VSM.
- Azaroon, Maedeh,Kiasat, Ali Reza
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- Technological method for preparing halogenated-3,4-dihydro-1H-2-naphthalenone
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The invention relates to a technological preparation method of halogenated-3,4-dihydro-1H-2-naphthalenone as shown in a formula (I). (As shown in the description). According to the method disclosed by the invention, through a cheap raw material namely 2,4-dihalogeno-benzene carbonitrile, and an intermediate namely 2,4-dihalogeno-benzene acetic acid is synthesized, and through a reusable trifluoroacetic anhydride/acid system catalyst, a target product namely the halogenated-3,4-dihydro-1H-2-naphthalenone is synthesized. According to the method disclosed by the invention, a large quantity of catalysts such as aluminumtrichloride, and costly catalysts such as Rh, are not needed, and the reaction route can be shortened, so that a large quantity of reagents and time can be saved, and the industrial economic benefits can be greatly increased.
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- Preparation of novel magnetic dicationic ionic liquid polymeric phase transfer catalyst and their application in nucleophilic substitution reactions of benzyl halides in water
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PEG-based magnetic dicationic ionic liquid was successfully prepared and evaluated as phase-transfer catalyst for nucleophilic substitution reactions of benzyl halides for the synthesis of benzyl azides and cyanides from good to excellent yields at 90 °C in water. The reactions occur in water and furnish the corresponding benzyl derivatives in high yields. No evidence for the formation of by-product for example benzyl alcohol of the reaction was observed and the products were obtained in pure form without further purification.
- Godajdar, Bijan Mombani,Ansari, Bita
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- Ionic liquid-induced conversion of methoxymethyl-protected alcohols into nitriles and iodides using [Hmim][NO3]
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This Letter reports a one-pot efficient conversion of methoxymethyl-ethers into their corresponding nitriles and iodides using the ionic liquid, 1-methyl-3H-imidazolium nitrate ([Hmim][NO3]) under microwave irradiation. A variety of products were prepared in high yields using this method.
- Noei, Jalil,Mirjafari, Arsalan
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supporting information
p. 4424 - 4426
(2014/08/05)
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- Magnetic nanoparticles grafted with β-cyclodextrin-polyurethane polymer as a novel nanomagnetic polymer brush catalyst for nucleophilic substitution reactions of benzyl halides in water
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The polymer coated magnetic nanoparticles has gained significant attention for potential applications in biomedicine, separations, and magnetic storage. In this study, β-cyclodextrin-polyurethane polymer coated Fe 3O4 magnetic nanoparticle as a novel class of hybrid organic/inorganic molecular catalyst was successfully prepared and evaluated as solid-liquid phase-transfer catalyst and molecular host system for nucleophilic substitution reactions. The nanocomposite has demonstrated the ability to catalytic the nucleophilic substitution reaction of benzyl halides with thiocyanate, azide, cyanide and acetate anions in water. No evidence for the formation of by-products for example isothiocyanate or alcohol was observed and the products obtained in pure form without further purification. The nanomagnetic polymer brush catalyst was easily removed from solution via application of a magnetic field, allowing straightforward recovery and reuse. Results obtained from scanning electron microscopy (SEM) and vibrating sample magnetometery (VSM) show that the synthesized magnetic nanocomposite are superparamagnetic with a mean diameter of 59 nm. The grafting of β-cyclodextrin-polyurethane polymer to Fe3O4 magnetic nanoparticle is confirmed by Fourier transform infrared spectroscopy (FT-IR).
- Kiasat, Ali Reza,Nazari, Simin
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- Application of β-cyclodextrin-polyurethane as a stationary microvessel and solid-liquid phase-transfer catalyst: Preparation of benzyl cyanides and azides in water
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Application of water tolerant heterogeneous catalyst, β-cyclodextrin- polyurethane (β-CDPU) polymer, as an efficient microvessel and polymeric host system for nucleophilic substitution reaction of benzyl halides with cyanide and azide anions in water has been described. The reactions gave only pure products, which did not require any further purification. The most important features of this method are high yields, clean reactions and that the catalyst can be recovered and recycled.
- Kiasat, Ali Reza,Nazari, Simin
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p. 102 - 105
(2013/01/15)
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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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- 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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- Controlled conversion of phenylacetic acids to phenylacetonitriles or benzonitriles using bis(2-methoxyethyl)aminosulfur trifluoride
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A mild, efficient, and practical method for the one-step synthesis of benzonitriles from phenylacetic acids using bis(2-methoxyethyl)aminosulfur trifluoride is described. The reaction was easily extended to the synthesis of the corresponding phenylacetonitriles by inclusion of triethylphosphine.
- Kangani, Cyrous O.,Day, Billy W.,Kelley, David E.
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p. 914 - 918
(2008/09/17)
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- Spirodiclofen and spiromesifen - Novel acaricidal and insecticidal tetronic acid derivatives with a new mode of action
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The broad spectrum acaricides spirodiclofen (BAJ2740, trade name: Envidor) and spiromesifen (BSN2060, trade name: Oberon) with an additional excellent activity against whiteflies, both belong to the new chemical class of tetronic acid derivatives discovered at Bayer CropScience during the 1990s. The discovery process starting from herbicidal PPO (protoporphyrinogen oxidase) chemistry, the synthetic routes leading to the products, and some insight into process development of central intermediates is given. Spirodiclofen and spiromesifen have a new mode of action (interference with lipid biosynthesis), show no cross-resistance to any resistant mite or whitefly field population and are therefore valuable tools for resistance management.
- Bretschneider, Thomas,Benet-Buchholz, Jordi,Fischer, Reiner,Nauen, Ralf
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p. 697 - 701
(2007/10/03)
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- Synthesis, selective aldose reductase inhibitory profile and antihyperglycaemic potential of certain parabanic acid derivatives
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Synthesis and aldose reductase inhibitory profile of certain parabanic acid derivatives 1a-p is described. Also, the antihyperglycaemic potential of these compounds was studied. The most active inhibitors in this series were compounds 1 g, 1p, and 1o which showed inhibitory activity, 36.6, 90 and 91% respectively, at concentration 1 × 10-4. Their IC50 were 2 × 10-6, 7.5 × 10-8 and 5 × 10-8, respectively. Compound 1o exhibited pronounced antihyperglycaemic effect.
- Nabil Aboul-Enein,El-Azzounya,Maklad,Attia,Wiese
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p. 329 - 350
(2007/10/03)
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- METABOLISM OF CHLOROPHENYLALANINES IN CROP AND WEED PLANTS IN RELATION TO THE FORMATION OF POTENTIAL HERBICIDAL END PRODUCTS
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Metabolism of 12 synthetic D,L-chlorophenylalanines has been examined in several crop and weed plants.Twenty-five gram samples of excised shoots or leaves of bushbean, soybean, corn, pigweed, lambsquarters, and giant foxtail were allowed to metabolize 10-4 M solutions of the D,L-chlorophenylalanines for 24 hr in continuous light.The plant samples were then extracted in 80percent methanol and the soluble acidic metabolites fractionated into ether.Each ether concentrate was partially purified by fractional elution from a PrepSep C18 coloumn and then analysed by HPLC.Collected fractions were esterified with pentafluorobenzylbromide and examined by GC-MS to demonstrate the presence of PFB-esters of chlorophenylacetic, chlorobenzoic and/or chlorocinnamic acids.Since certain of these metabolites are known to be potent plant growth-regulators and herbicides, the results are discussed in relation to the potantial herbicidal action of certain chlorophenylalanines by the mechanism of 'lethal synthesis'.Key Word Index - Phaseolus vulgaris; Glycine max.; Leguminosae; Zea mays; Amaranthus retroflexus; Chenopodium album; Setaria faberii; metabolism; D,L-chlorophenylalanines; chlorophenylacetic acids; chlorobenzoic acids; chlorocinnamic acids; growth regulators.
- Taylor, David C.,Wightman, Frank,Kazakoff, Clem W.
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