- 1,3,2,4-diazadiphosphetidine-based phosphazane oligomers as source of P(III) atom economy reagents: Conversion of epoxides to vic -haloalcohols, vic -dihalides, and alkenes in the presence of halogen sources
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1,3,2,4-Diazadiphosphetidines (P1-P3), as easily prepared, stable, and heterogeneous P(III) compounds, were used for the efficient conversion of epoxides to vic-halohydrins, vic-dihalides, or alkenes in the presence of different halogen sources in CH3CN. Of these phosphazanes, P3 is most suitable and contains 4 phosphorous atoms with the advantage of having greater atom economy and its phosphorus oxide byproduct can be easily separated from the reaction mixture by simple filtration. The nitrogen atoms in this molecule can also act as acid scavengers in the reaction.
- Iranpoor, Nasser,Firouzabadi, Habib,Etemadidavan, Elham
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p. 1165 - 1173
(2014/10/16)
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- Solvent-free biocatalytic interesterification of acrylate derivatives
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The ability of diverse commercial lipases and whole cells (fungal resting cells) to synthesise allyl and dichloropropyl acrylate from allyl dodecanoate through an interesterification process is presented. The process was carried out without solvent in a conventional batch system. The best biocatalyst among those studied was the commercial enzyme CALB (Candida antarctica lipase B immobilised onto a macroporous acrylic resin). The reaction was sensitive to water activity, and a decrease in the yield was observed at the highest activity studied. CALB could also be applied to diverse acrylic derivatives, although the yields decreased using either ethyl methacrylate or acrylic acid.
- Yara-Varón, Edinson,Eras Joli, Jordi,Torres, Mercè,Sala, Nuria,Villorbina, Gemma,Méndez, Jonh Jairo,Canela-Garayoa, Ramon
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- Direct functionalization of labile alkoxyamines
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Direct esterification of a labile alkoxyamine R1R 2NOR3, which was previously reported as unsuccessful, is achieved by a Mitsunobu reaction or a nucleophilic substitution. Ester derivatives are obtained under smooth conditions and easily purified. Macrocyclization attempts on ester derivatives were successful for five-membered ring lactones and unsuccessful for 13-membered ring lactones. Moreover, the success of the cyclization was dramatically dependent on the quality of the solution degassing. Poor degassing led to unexpected carbonate alkoxyamine.
- Brémond, Paul,Kabytaev, Kuanysh,Marque, Sylvain R.A.
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body text
p. 4543 - 4547
(2012/09/25)
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- Rhenium-catalyzed allylation of C-H bonds of benzoic and acrylic acids
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We have succeeded in the allylation of aromatic and olefinic C-H bonds of benzoic and acrylic acids using a rhenium catalyst, Re2(CO) 10. In this reaction, isomerization of the introduced allyl group to the 1-propenyl group did not occur.
- Kuninobu, Yoichiro,Ohta, Kazuhiro,Takai, Kazuhiko
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supporting information; experimental part
p. 10791 - 10793
(2011/11/05)
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- METHOD FOR SYNTHESIZING ALLYL METHACRYLATE
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The present invention relates to a process for preparing allyl methacrylate, comprising the reaction of allyl alcohol with an ester of methacrylic acid, wherein the reaction is catalysed by zirconium acetylacetonate. The process according to the invention enables particularly favourable preparation of allyl methacrylate with a very high purity.
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Page/Page column 4
(2010/08/07)
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- Silphos [PCl3-n(SiO2)n]: A heterogeneous phosphine reagent for the conversion of epoxides to β-bromoformates or alkenes
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Silphos [PCl3-n(SiO2)n] as a heterogeneous phosphine reagent is efficiently applied for the transformation of epoxides to β-bromoformates in the presence of bromine or N-bromosuccinimide in dimethyl formamide at 0 °C. The combination of Silphos and iodine was also found suitable for the room temperature preparation of alkenes. The use of Silphos provides the advantage of easy separation of the phosphine oxide by-product from the reaction mixture.
- Iranpoor, Nasser,Firouzabadi, Habib,Jamalian, Arezu
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p. 1823 - 1827
(2007/10/03)
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- Regioselective synthesis of vic-halo alcohols and symmetrical or unsymmetrical vic-dihalides from epoxides using triphenylphosphine -N-halo imides
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A simple, novel, and highly regioselective cleavage of epoxides into vicinal halo alcohols and symmetrical or unsymmetrical dihalides is described using different stoichiometries of triphenylphosphine (PPh3) and N-halo succinimide (NXS) or N-halo saccharine (NXSac).
- Iranpoor, Nasser,Firouzabadi, Habib,Azadi, Roya,Ebrahimzadeh, Farzaneh
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- Rapid, highly efficient and stereoselective deoxygenation of epoxides by ZrCl4/NaI
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An effective and highly chemoselective method is described for the rapid deoxygenation of different epoxides to the corresponding olefins using ZrCl 4/NaI in anhydrous CH3CN, in excellent yields and with retention of relative stereochemistry.
- Firouzabadi, Habib,Iranpoor, Nasser,Jafarpour, Maasoumeh
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p. 4107 - 4110
(2007/10/03)
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- Allylation of Alcohols and Carboxylic Acids with Allyl Acetate Catalyzed by [Ir(cod)2]+BF4- Complex
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A facile method for the synthesis of allyl alkyl ethers from alcohols with allyl acetate was developed by the use of [Ir(cod)2] +BF4- complex. For instance, the reaction of allyl acetate with n-octyl alcohol in the presence of a catalytic amount of [Ir(cod)2]+BF4- complex afforded allyl octyl ether in quantitative yield. Allyl carboxylates were also prepared by the exchange reaction between carboxylic acids and allyl acetate in good yields. The [Ir(cod)2]+BF4- complex catalyzed the reaction of alkyl and aromatic amines with allyl acetate to lead to the corresponding allylamines in fair to good yields.
- Nakagawa, Hideto,Hirabayashi, Tomotaka,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 3474 - 3477
(2007/10/03)
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- Rhenium-Catalyzed Epoxide Deoxygenation: Scope and Limitations
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Transfer of oxygen atoms from epoxides to triphenylphosphine is efficiently catalyzed by Tp′ReO3 [Tp′ = hydrido-tris-(3,5-dimethylpyrazolyl)borate] in benzene at 75-105 °C. The reaction tolerates a wide variety of functional groups including ketones (conjugated or non-conjugated to the new double bond), esters, nitriles, ethers, silyl ethers and phthalimides. Relative rates vary with substitution pattern and electronics; in general, monosubstituted and 2,2-disubstituted epoxides react fastest, and cis-2,3-disubstituted systems react faster than trans. Electron-withdrawing substituents promote the reaction.
- Gable, Kevin P.,Brown, Eric C.
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p. 2243 - 2245
(2007/10/03)
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- Process for the conversion of aldehydes to esters
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A process for the conversion of aldehydes to esters, specifically acrolein or methacrolein to methyl acrylate or methyl methacrylate, respectively. Essentially in the absence of water, an aldehyde is contacted with an oxidizing agent to form an intermediate and then the intermediate is contacted with a diol or an alcohol to form an ester or diester. Preferably, the oxidizing agent is also a chlorinating agent. Specifically, acrolein or methacrolein is contacted with an oxidizing/chlorinating agent, such as t-butyl hypochlorite, and the chlorinated compound is contacted with an alcohol, such as methanol, to form methyl acrylate or methyl methacrylate, respectively. Generally, the order of addition is for the oxidizing agent to be added to the aldehyde, specifically for t-butyl hypochlorite to be added to acrolein or methacrolein, and for the diol or alcohol to be added to the intermediate, specifically for the methanol to be added to the reaction product of acrolein or methacrolein and t-butyl hypochlorite. The process of the present invention can be carried out in the absence or in the presence of solvent. Generally, better methyl acrylate or methyl methacrylate yields are obtained at lower reaction temperatures.
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Page/Page column 4
(2010/01/31)
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- Enhancement of the efficiency of the low temperature method for kinetic resolution of primary alcohols by optimizing the organic bridges in porous ceramic-immobilized lipase
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For the enhancement of enantioselectivity and acceleration of the reaction rate in the lipase-catalyzed resolution of primary alcohols, the use of a very low reaction temperature (-30 °C) and an immobilized lipase on organic bridges-coated porous ceramic support was found to be highly effective. Furthermore, the structure of the organic bridges greatly influenced the temperature effect between in E and 1/T as well as the reaction rate. Among the organic bridges examined in the resolution of (±)-2-hydroxymethyl-1,4-benzodioxane, the 6-(2-methylpropanoyloxy)hexylsilanetrioxyl bridge was the best choice for both the E value and the reaction rate at -30 °C.
- Sakai, Takashi,Hayashi, Kyoko,Yano, Fumika,Takami, Mie,Ino, Megumi,Korenaga, Toshinobu,Ema, Tadashi
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p. 1441 - 1446
(2007/10/03)
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- Polymerizable dye
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Dye monomers of the general chemical formula STR1 where X denotes an unsaturated polymerizable organic radical; and R is an organic diradical with 2 to 12 carbon atoms.
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