- A phosphonium ylide as a visible light organophotoredox catalyst
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A phosphonium ylide-based visible light organophotoredox catalyst has been designed and successfully applied to halohydrin synthesis using trichloroacetonitrile and epoxides. An oxidative quenching cycle by the ylide catalyst was established, which was confirmed by experimental mechanistic studies.
- Toda, Yasunori,Tanaka, Katsumi,Matsuda, Riki,Sakamoto, Tomoyuki,Katsumi, Shiho,Shimizu, Masahiro,Ito, Fuyuki,Suga, Hiroyuki
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supporting information
p. 3591 - 3594
(2021/04/14)
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- SULFONIMIDAMIDE COMPOUNDS AS NLRP3 MODULATORS
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Described herein are compounds of Formula (I), Formula (I-A), and Formula (I-B), solvates thereof, tautomers thereof, and pharmaceutically acceptable salts of the foregoing, Further described herein are methods of inhibiting NLRP3 using said compounds, and methods of and compositions useful in treating NLRP3-dependent disorders.
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Paragraph 0784
(2021/07/31)
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- MBA-cross-linked poly(N-vinyl-2-pyrrolidone)/ferric chloride macromolecular coordination complex as a novel and recyclable Lewis acid catalyst: Synthesis, characterization, and performance toward for regioselective ring-opening alcoholysis of epoxides
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A novel macromolecular-metal coordination complex, MBA-cross-linked PNVP/FeCl3 material was fabricated by immobilization of water intolerant ferric chloride onto the porous cross-linked poly(N-vinyl-2-pyrrolidone) carrier beads as a macromolecular ligand or carrier which was prepared by suspension free-radical copolymerization of N-vinyl-2-pyrrolidone (NVP) and N,N′-methylene bis-acrylamide (MBA) as a crosslinking agent in water. The obtained PNVP/FeCl3 was characterized by UV/vis and FT-IR spectroscopies, TGA, FE-SEM, EDX, and ICP techniques. This heterogenized version of ferric chloride is a convenient and safe alternative to highly water intolerant ferric chloride. The catalytic performance of (PNVP/FeCl3) as an efficient and recyclable polymeric Lewis acid catalyst was appropriately probed in the regio-and stereoselective nucleophilic ring opening of various epoxides with various alcohols in excellent yields with TOF up to 182.48 h?1 without generating any waste. The activity data indicate that this heterogeneous catalyst is very active and could be easily recovered, and reused at least six times without appreciable loss of activity indicating its stability under experimental conditions.
- Rahmatpour, Ali,Zamani, Maryam
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- Selective monochlorination of unsymmetrical vicinal diols with chlorinated iminium chlorides
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Chlorinated iminium chlorides have been identified to promote the highly efficient and selective mono-chlorination of unsymmetrical vicinal diols. Vilsmeier reagent, namely, (chloromethylene)dimethyliminium chloride, enables highly reactive and regioselective chlorination of 1,2- and 1,3-diols featured one secondary benzylic hydroxy group and one primary aliphatic hydroxy group to give the corresponding 1,2- and 1,3-chlorohydrins. Viehe's salts (α,α-dichloro iminium salts) exhibit excellent reactivity and good selectivity for vicinal diols to give the corresponding chlorohydrin carbamates via a cyclic intermediate in situ. The chlorination protocols tolerate diverse functional groups, including halogens, naphthalene rings, nitro, and cyano. Moreover, the optical purity of chiral diols could be retained during this chlorination reaction.
- Li, Chengyang,Li, Xiaotong,Wang, Yu,Wu, Xiaoyu,Xie, Xiaomin,Yang, Liqun,Zhang, Zhaoguo
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- Visible-light-triggered Catalytic Halohydrin Synthesis from Epoxides and Trichloroacetonitrile by Copper and Iron Salts
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Preparation of vicinal halohydrins, in which copper or iron chlorides catalyze the ring-opening reaction of epoxides with visible light effectively, is described. The use of trichloroacetonitrile as a halogen source enables catalytic HCl generation under the mild conditions. This method can also be applied to the aziridine ring-opening reaction.
- Toda, Yasunori,Tanaka, Katsumi,Matsuda, Riki,Suga, Hiroyuki
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supporting information
p. 1469 - 1471
(2019/12/02)
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- An epoxide ring-opening reaction by using sol–gel-synthesized palladium supported on a strontium hydroxyl fluoride catalyst
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Palladium supported on a strontium hydroxyl fluoride catalyst was synthesized by a one-pot fluorolytic sol–gel method. The prepared catalyst was characterized by various physicochemical techniques. The sol–gel method has led to the formation of a high surface area (57?m2g?1), mesoporous (pore diameter?=?13.0?nm) catalyst with uniform dispersion of Pd nanoparticles of size ～7?nm on the surface of strontium hydroxyl fluoride. The catalyst was used for epoxide alcoholysis, and 100% conversion was obtained with 96% selectivity for β-alkoxy alcohols under mild conditions. The catalyst could be recycled for up to three catalytic cycles without any appreciable decrease in conversion and selectivity, indicating the stability of the catalyst under the reaction conditions. Further, the mechanism of alcoholysis was proposed on the basis of the physicochemical characteristics of the catalyst and on the basis of the products formed during the catalytic reaction.
- Acham, Vaibhav R.,Dongare, Mohan K.,Kemnitz, Erhard,Umbarkar, Shubhangi B.
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p. 1237 - 1246
(2016/10/13)
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- Efficient and regioselective ring-opening of epoxides with alcohols and sodium azide by using catalytic amounts of gacl3/polyvinylpyrrolidone
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A new polymeric catalyst was prepared by supporting GaCl3 on cross-linked polyvinylpyrrolidone (GaCl3/ PVP). This catalyst was employed for efficient and regioselective ring-opening reaction of epoxides by various alcohols under solvent-free conditions at room temperature. In our procedure, this heterogeneous catalyst was used at neutral and mild reaction conditions to afford high yields of β-alkoxy alcohols. Also, regioselective conversion of epoxides to β-azidohydrines was accomplished by sodium azide in MeOH in the presence of GaCl3/PVP at room temperature. GaCl3/PVP is a non-hygroscopic and recoverable catalyst and is easily separated from reaction mixture by a simple filtration and re-used repeatedly. Also, this catalyst has good handling and can be stored for long time without any reducing of its reactivity.
- Pourali, Ali Reza,Ghayeni, Samaneh,Afghahi, Fatemeh
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p. 1741 - 1744
(2013/07/26)
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- "Metal ion electrophilic catalysis" in ring-opening reactions of 1,2-epoxides by metal halides in ionic liquids
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Metal ion electrophilic catalysis (Li+ > Na+ ? K+) has been found in ring-opening reactions of 1,2-epoxides 1-5 by metal halides MHa1 in ionic liquids. The results have been rationalized on the basis of a transition state where the cation M+ stabilizes the negative charge developing on the oxygen atom of the oxirane ring while favoring the nucleophilic attack at the adjacent carbon by the ion-paired anion Hal -. Georg Thieme Verlag Stuttgart.
- Betti, Cecilia,Landini, Dario,Maia, Angelamaria
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p. 1335 - 1338
(2007/10/03)
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- Facile and regioselective conversion of epoxides into β-chlorohydrins using ZrCl4
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Epoxides were efficiently converted into the corresponding β-chlorohydrins in good yields by treatment with ZrCl4 in acetonitrile.
- Smitha,Reddy, Ch. Sanjeeva
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p. 300 - 301
(2007/10/03)
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- 1,2-Ferrocenediylazaphosphinines 2: A new class of nucleophilic catalysts for ring-opening of epoxides
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1,2-Ferrocenediylazaphosphinines (1a-c) have been successfully employed as a new class of nucleophilic catalysts for ring-opening of a range of epoxides, their catalytic efficiency in terms of regioselectivity as well as chemical yield comparing well with the existing catalysts in the literature. In contrast, low enantiomeric excesses have been obtained from the reactions of meso-epoxides catalyzed by (R)-1.
- Paek, Seung Hwan,Shim, Sang Chul,Cho, Chan Sik,Kim, Tae-Jeong
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p. 849 - 851
(2007/10/03)
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- Synthesis of tetrahydrofurans by the reaction of α,β-epoxy alcohol derivatives with allylsilanes
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In the presence of SnCl4, α,β-epoxy alcohol derivatives easily reacted with allylsilanes to give the corresponding tetrahydrofurans in moderate yields.
- Sugita, Yoshiaki,Kimura, Yoko,Yokoe, Ichiro
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p. 5877 - 5880
(2007/10/03)
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- Organic co-solvents restore the inherently high enantiomeric ratio of lipase B from Candida antarctica in hydrolytic resolution by relieving the enantiospecific inhibition of product alcohol
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The enantiomeric ratio in the hydrolysis of racemic 3-chloro-1- phenylmethoxy-2-propyl butanoate with lipase B from Candida antarctica, CALB, is raised from E=50 to E=180 upon addition of acetone to the aqueous medium. This co-solvent effect is now explained as an enantiospecific inhibition of the lipase by the liberated alcohol. In the range from 0 to 30% acetone, the effect correlates with the increased solubility of the alcohol in the reaction medium. Free and immobilized CALB show similar behaviour.
- Lundhaug, Kamilla,Overbeeke, P.L. Antoine,Jongejan, Jaap A.,Anthonsen, Thorleif
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p. 2851 - 2856
(2007/10/03)
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- Regio- and stereoselective ring opening of 2,3-epoxyalcohols with diethylaluminium azide
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2,3-Epoxyalcohols react with diethylaluminium azide under mild conditions to give 3-azido-1,2-diols resulting from the regio- and stereoselective attack of the nucleophile at the epoxide C-3. The high regioselectivity (>25:1) observed with both cis and trans substituted epoxides is not affected by bulky substituents at C-3. The method has been successfully applied also to the synthesis of diaminodiol dipeptide isosteres.
- Benedetti, Fabio,Berti, Federico,Norbedo, Stefano
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p. 7971 - 7974
(2007/10/03)
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- Enzymatic resolution of butanoic esters of 1-phenylmethyl and 1-[2-phenylethyl]ethers of 3-chloro-1,2-propanediol
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The enzymatic hydrolysis of butanoic esters of 1-phenylmethyl- and 1-[2-phenylethyl] ethers of 3-chloro-1,2-propanediol has been studied by using lipases. Highest enantiomeric ratio was obtained with PPL for the phenylmethyl ether and with Amano SAM II for the phenylethyl ether. The absolute configurations of the products was verified in two ways. Both the produced alcohols and the remaining esters were converted into the corresponding glycidyl ethers which also were synthesised in homochiral forms starting from (S)-epichlorohydrin. The produced alcohols and the remaining esters were prepared independently from (S)-epichlorohydrin.
- Partali,Waagen,Alvik,Anthonsen
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p. 961 - 968
(2007/10/02)
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- Selective monoalkylation of acyclic diols by means of dibutyltin oxide and fluoride salts
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Fluoride anion was found to promote monoalkylation reaction of diols by the stannylene acetal method, and selective monoalkylation of various acyclic diols was accomplished in good yields under mild conditions by employing this new method. Functional groups such as carboxylic acid ester, carboxamide, carbamate, nitrile, alkyl chloride, and ether were not affected under the reaction conditions.
- Nagashima,Ohno
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p. 1972 - 1982
(2007/10/02)
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- Liquid-Liquid-Extraction of Metal Ions with Lariat Ethers
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Lariat ethers of various ring size and substitution are synthesized and characterized by physical data and chemical analysis.The extraction behaviour of the crown compounds towards Na+, K+, Cs+ and Ag+ in a picric acid solution has been investigated.The extraction constants for 1:1 and 1:2 complexes are determined using the equilibrium distribution data.The results show that the flexible side chain in the investigated compounds has in no case a positive effect on the metal picrate extraction.
- Gloe, K.,Muehl, P.,Beger, J.,Poeschmann, C.,Petrich, M.,Beyer, L.
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p. 413 - 421
(2007/10/02)
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- Enzymes in Organic Synthesis: Synthesis of Highly Enantiomerically Pure 1,2-Epoxy Aldehydes, Epoxy Alcohols, Thiirane, Aziridine, and Glyceraldehyde 3-Phosphate
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This paper describes a chemoenzymatic procedure for the synthesis of (R)- and (S)-glycidaldehyde diethyl acetal (4 and 5). 2-Acetoxy-3-chloropropanal diethyl acetal (1c) was enantioselectively hydrolyzed by LP-80 lipase to give (S)-3-chloro-2-hydroxypropanal diethyl acetal (2c) and the unreacted acetate (3c), both in >95percent calculated yield and >98percent ee.Both products were subsequently converted to epoxides 4 and 5, respectively.Resolutions of 2-acetoxy-1-(benzyloxy)-3-chloropropane (11a) and 3-(allyloxy)-2-acetoxypropyl p-toluenesulfonate (14b) were similarly carried out to give the corresponding optically active 2-hydroxy and 2-acetoxy derivatives in 90percent and >95percent ee.These products were subsequently converted to the corresponding 1,2-epoxides.Nucleophilic opening of epoxide 4 was exemplified by the syntheses of (R)-3-azido-2-hydroxypropanal and D-glyceraldehyde 3-phosphate.Conversion of the chiral epoxides to thiirane and aziridine was also described.
- Pederson, Richard L.,Liu, Kevin K.-C.,Rutan, James F.,Chen, Lihren,Wong, Chi-Huey
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p. 4897 - 4901
(2007/10/02)
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- Organotin Phosphate Condensates as a Catalyst of Selective Ring-Opening of Oxiranes by Alcohols
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The highly regioselective alcoholysis of oxiranes is catalyzed by organotin phosphate condensates, providing a variety of β-alkoxy alcohols in good yields.The selectivity of the nucleophilic attack is dependent on the structures of epoxides.The gem-dialkyloxiranes are cleaved on the tertiary carbon, while β,γ-epoxy alcohols and their derivatives gave C-3 attack products.The anti stereoisomers are solely produced in the latter case.Thus the catalysis is both acidic and coordinative.Of practical importance is the recycled use of the catalyst without any appreciable decrease in the activity and the selectivities.
- Otera, Junzo,Niibo, Yoshihisa,Tatsumi, Naofumi,Nozaki, Hitosi
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p. 275 - 278
(2007/10/02)
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- HIGHLY REGIOSELECTIVE RING OPENING OF EPOXIDES WITH ALCOHOLS CATALYZED BY ORGANOTIN PHOSPHATE CONDENSATES
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Organotin phosphate condensates proved to catalyze the ring opening reaction of epoxides with alcohols in a highly regioselective manner.
- Otera, Junzo,Yoshinaga, Yukari,Hirakawa, Kazuhisa,Nakata, Tetsuya
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p. 3219 - 3222
(2007/10/02)
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- Crown ether compositions with sidearms affording enhanced cation binding
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This invention relates to novel crown ether compositions which have been given the cognomen "lariat ethers". They have been designed with one or more arms bearing neutral donor groups capable of interacting with a complexed metal ion and thereby affording enhanced cation binding compared to simple crown ethers. Evidence of enhanced cation binding has been obtained and the compounds have also shown utility as phase transfer catalysts.
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- Enhancement of Cation Binding in Lariat Ethers Bearing a Methyl Group at the Quaternary, Pivot Carbon Atom
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A number of carbon-pivot lariat ethers have been prepared and compared, with their counterparts having a methyl group bonded to the side-arm-bearing or pivot carbon.All of the compounds examined are 15-crown-5 derivatives, and in this series, the methyl lariats invariably show a higher affinity for sodium than do the nonmethylated species.The results are less consistent in the case of potassium cation which is larger than the 15-crown-5 compound's cation binding hole.The enhanced stability constant observed for sodium with the methyl lariats is attributed to reduced s ide-arm mobility or conformational changes in either the side arm or macroring.
- Nakatsuji, Yohji,Nakamura, Tetsuya,Okahara, Mitsuo,Dishong, Dennis M.,Gokel, George W.
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p. 1237 - 1242
(2007/10/02)
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- Crown Cation Complex Effects. 20. Syntheses and Cation Binding Properties of Carbon-Pivot Lariat Ethers
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In an effort devise synthetic cation binders that will mimic the behavior of naturally occuring ionophores such as valinomycin, we have prepared approximately 30 macrocyclic (crown) polyethers bearing flexible side chains attached to the macro ring at carbon.In many of these "carbon-pivot" compounds, the side chain contains one or more neutral donor groups that, if in a suitable geometrical arrangement, may provide additional solvation to the macro-ring-bound cation.Although such donors often enhanced the cation binding ability, overall, the increases in stability constants were modest.The physical resemblance and concept of "roping and tying" the cation suggest the name "lariat ethers".Syntheses of these molecules and binding by them of Na+ and K+ cations are reported and conclusions drawn about the structural requirements and cation binding efficacy of these materials.
- Dishong, Dennis M.,Diamond, Craig J.,Cinoman, Michael I.,Gokel, Geoge W.
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p. 586 - 593
(2007/10/02)
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- ALCOOLYSE DE L'EPICHLORHYDRINE DU GLYCEROL SUR CATALYSEUR SOLIDE. SYNTHESE COMMODE D'ETHERS DU CHLORO-3 PROPANE DIOL-1,2.
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Monoethers of 3-chloro-1,2 propanediol were easily obtained in good yields from epichlorohydrin and alcohols under catalysis of actived montmorillonite K 10.
- Thuy, Vu Moc,Petit, Huguette,Maitte, Pierre
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p. 261 - 262
(2007/10/02)
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