- Synthesis of Phospholipids using an Inverse Phosphite Triester Approach
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1,2-Diacylglycerols, prepared from allyl protected precursors, were transformed into glycerophosphatidylcholines through an acid catalysed coupling with a dialkyl phosphoramidite, followed by a one step deprotection-substitution reaction.
- Hebert, Normand,Just, George
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- Microwave-assisted, rapid cycloaddition of allyl glycidyl ether and CO 2 by employing pyridinium-based ionic liquid catalysts
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This study investigated the use of pyridinium-based ionic liquids (ILs) as an efficient catalyst for the rapid solvent-free microwave-assisted cycloaddition of allyl glycidyl ether (AGE) and CO2 to yield allyl glycidyl carbonate (AGC) under moderate reaction conditions. The cycloaddition reaction occurred over a short reaction time of 30 s, resulting in a high turnover frequency (TOF) ranging from 200 to 7000 h- 1. The effects of alkyl chain length and anion of pyridinium-based catalysts on the cycloaddition reactivity were studied. The effects of reaction parameters such as the amount of catalyst, microwave power, CO2 pressure, and reaction time were also investigated.
- Tharun, Jose,Kathalikkattil, Amal Cherian,Roshan, Roshith,Kang, Dong-Heon,Woo, Hee-Chul,Park, Dae-Won
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- Synthesis of a plasmenylethanolamine
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A concise synthesis of a plasmenylethanolamine (PlsEtn-[16:0/18:1 n-9]), known as antioxidative phospholipids commonly found in cell membranes, has been achieved from an optically active known diol through 8 steps. The key transformations for the synthesis of PlsEtn-[16:0/18:1 n-9] are (1) regio- A nd Z-selective vinyl ether formation via the alkylation of a lithioalkoxy allyl intermediate with an alkyl iodide, and (2) a one-pot phosphite esterification-oxidation sequence to construct the ethanolamine phosphonate moiety in the presence of the vinyl ether functionality. The piperidine salt of synthetic PlsEtn-[16:0/18:1 n-9] was desalinated through reversed-phase high-performance liquid chromatography purification.
- Asano, Yoshio,Enomoto, Masaru,Inoue, Tsubasa,Kuwahara, Shigefumi,Maeda, Satoshi,Mohri, Tomoyo,Nakagawa, Kiyotaka,Ogura, Yusuke,Otoki, Yurika
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- Discovery of lipids from B. longum subsp. infantis using whole cell MALDI analysis
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Bifidobacteria are dominant members of the microbial community in the intestinal tract of infants, and studies have shown that glycolipids extracted from the cell surface of these bacteria elicit beneficial immune responses. Accordingly, the identification and structural characterization of glycolipids from the cell wall of bifidobacteria is the first step in correlating glycolipid structure with biological activity. Using whole cell MALDI as a screening tool, we herein present for the first time the identification and structural elucidation of the major polar lipids from Bifidobacterium longum subs. infantis. The lipids identified include an unprecedented plasmenyl cyclophosphatidic acid and a mixed acetal glycolipid, with the latter subsequently being isolated and found to suppress the innate immune response.
- Timmer, Mattie S. M.,Sauvageau, Janelle,Foster, Amy J.,Ryan, Jason,Lagutin, Kirill,Shaw, Odette,Harper, Jacquie L.,Sims, Ian M.,Stocker, Bridget L.
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- Room-temperature self-healing polymers based on dynamic-covalent boronic esters
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Cross-linked polymers constructed with dynamic-covalent boronic esters were synthesized via photoinitiated radical thiol-ene click chemistry. Because the reversibility of the boronic ester cross-links was readily accessible, the resulting materials were capable of undergoing bond exchange to covalently mend after failure. The reversible bonds of the boronic esters were shown to shift their exchange equilibrium at room temperature when exposed to water. Nevertheless, the materials were observed to be stable and hydrophobic and absorbed only minor amounts of water over extended periods of time when submerged in water or exposed to humid environments. The facile reversibility of the networks allowed intrinsic self-healing under ambient conditions. Highly efficient self-healing of these bulk materials was confirmed by mechanical testing, even after subjecting a single site to multiple cut-repair cycles. Several variables were considered for their effect on materials properties and healing, including cross-link density, humidity, and healing time.
- Cash, Jessica J.,Kubo, Tomohiro,Bapat, Abhijeet P.,Sumerlin, Brent S.
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- Structurally Simple Benzylidene-Type Photolabile Diol Protecting Groups
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Two structurally simple photolabile protecting groups for releasing 1,2- and 1,3-diols have been developed. The diols can be protected in high yields and released from their corresponding acetals with high chemical efficiency.
- Ding, Xiong,Devalankar, Dattatray A.,Wang, Pengfei
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- Zwitterionic Quaternary Ammonium Alkoxides: Organic Strong Bases
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Stable quaternary ammonium alkoxides, a new type of organic strong base, were obtained from unhindered tertiary alkanolamines and glycidol.At elevated temperatures, the 2-hydroxyethyl derivatives underwent intramolecular rearrangements and deoxyalkylation to form tertiary amine terminated 1,4-poly(3-hydroxyoxetanes).Demethylation was also observed.The 3-hydroxypropyl derivative underwent disproportionation and Hofmann elimination in addition.
- Lovett, Eva G.
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- Aqueous-microwave synthesized carboxyl functional molecular ribbon coordination framework catalyst for the synthesis of cyclic carbonates from epoxides and CO2
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A carboxyl-containing coordination polymer catalyst {Cu(Hip) 2(Bpy)}n (CHB) was synthesized rapidly in an aqueous medium using microwave energy and characterized for its structure, morphology, acid-base sites and heterogeneity using experimental and physicochemical techniques. The microwave route was established as competent with the hydrothermal pathway. Exploration of the coordination modes of metal-organic framework (MOF) ligands, especially carboxyl spacers, in achieving reactive functional groups is herein illustrated as crucial rather than focusing merely on the porosity of MOF catalysts. The work represents the first report of a carboxyl-containing MOF class material employed for synthesizing cyclic carbonates from epoxide and CO2. The metal-carboxyl mediated cycloaddition of allyl glycidyl ether and CO2 by the cooperative influence of Cu2+ and the COOH of CHB was synergistically enhanced by an ionic liquid co-catalyst to obtain allyl glycidyl carbonate in 89% yield at optimised reaction conditions. The epoxide substrate scope, effect of reaction parameters and catalyst recyclability (up to 5 cycles) were also studied.
- Kathalikkattil, Amal Cherian,Kim, Dong-Woo,Tharun, Jose,Soek, Han-Geul,Roshan, Roshith,Park, Dae-Won
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- Synthesis and Evaluation of New Polyurethane - Based Material for Ion Separation
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The polyaddition of macrocyclic diols with diisocyanates is an easy way to prepare ionselective polymers bearing pendant crown ethers.Those polymers can be readily immobilized on silicagel, with no change of ionselective properties.
- Favre-Reguillon, Alain,Dumont, Nathalie,Dunjic, Branko,Lemaire, Marc
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- Bifunctional organocatalysts for the conversion of CO2, epoxides and aryl amines to 3-aryl-2-oxazolidinones
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A route to synthesize 3-aryl-2-oxazolidinones is developed, which is achieved through a three component reaction between CO2, aryl amines, and epoxides with a binary organocatalytic system composed of organocatalysts and DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). The method allows wide scopes of epoxide and aryl amine substrates with various functional groups under mild reaction conditions. The control experiments indicate that a cyclic carbonate is formed via cycloaddition of epoxides with CO2, which further reacts with the β-amino alcohol originating from epoxides and aryl amines, resulting in the formation of 3-aryl-2-oxazolidinones finally.
- Xie, Ya-Fei,Guo, Cheng,Shi, Lei,Peng, Bang-Hua,Liu, Ning
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supporting information
p. 3497 - 3506
(2019/04/14)
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- MACROCYCLIC MCL-1 INHIBITORS AND METHODS OF USE
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The present disclosure provides for compounds of Formula (I) wherein A2, A3, A4, A6, A7, A8, A15, RA, R5, R9, R10A, R10B, R11, R12, R13, R14, R16, W, X, and Y have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents in the treatment of diseases and conditions, including cancer. Also provided are pharmaceutical compositions comprising compounds of Formula (I).
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Paragraph 00255; 00262
(2019/03/05)
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- Macrocyclic MCL-1 inhibitors and methods of use
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The present disclosure provides for compounds of Formula (I) wherein A2, A3, A4, A6, A7, A8, A15, RA, R5, R9, R10A, R10B, R11, R12, R13, R14, R16, W, X, and Y have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents for the treatment of diseases and conditions, including cancer. Also provided are pharmaceutical compositions comprising compounds of Formula (I).
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Paragraph 1049
(2019/02/28)
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- MACROCYCLIC MCL-1 INHIBITORS AND METHODS OF USE
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The present disclosure provides for compounds of formula (I), wherein A2, A3, A4, A6, A7, A8, A15, RA, R5, R9, R10A, R10B, R11, R12, R13, R14, R16, W, X, and Y have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents in the treatment of diseases and conditions, including cancer. Also provided are pharmaceutical compositions comprising compounds of formula (I).
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Paragraph 00153
(2019/03/05)
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- MnIII Porphyrins: Catalytic Coupling of Epoxides with CO2 under Mild Conditions and Mechanistic Considerations
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A series of 5,10,15,20-tetrakis(2,3-dichlorophenyl)porphyrinate complexes of manganese(III) [MnIII(T2,3DCPP)X] with six different axial ligands (X=NO3 ?, AcO?, IO3 ?, Br?, Cl?, HO?) were investigated as catalysts in the cycloaddition reactions of CO2 and styrene oxide (SO), under mild conditions, i. e., atmospheric pressure and 60 °C. [MnIIIT(2,3DCPP)IO3] showed the best catalytic performance, selectively producing the respective cyclic carbonate from diverse epoxides using tetrabutylammonium bromide as a nucleophile source. Mechanistic considerations were inferred from electronic spectra and spectrophotometric titrations, showing that there are a series of equilibriums involved in the formation of the catalytic active species. Stability constants for the proposed equilibrium models were determined using SQUAD software. A catalytic cycle has been proposed based on those observations.
- Milani, Jorge L. S.,Meireles, Alexandre M.,Bezerra, Werberson A.,Martins, Dayse. C. S.,Cangussu, Danielle,das Chagas, Rafael P.
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p. 4393 - 4402
(2019/08/01)
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- Straightforward synthesis of MTW-type magnesium silicalite for CO2 fixation with epoxides under mild conditions
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Aluminum-free magnesium silicalite with MTW topology (Mg-Si-ZSM-12) was fabricated via a straightforward hydrothermal synthesis route involving an initial acid co-hydrolysis step. Mg incorporation endowed superior basic properties to the MTW framework, as illustrated by CO2 sorption and temperature programmed desorption plus the activity in a typical basic reaction, Knoevenagel condensation. Mg-Si-ZSM-12 catalyzed the coupling of atmospheric CO2 with epoxides and led to the efficient production of cyclic carbonates with high yield and selectivity at relatively low temperature (down to 60 °C). The present strategy afforded a zeolitic solid base with regular 12-membered ring microporous channels that has potential application in CO2 fixation.
- Wen, Haimeng,Xie, Jingyan,Zhou, Yang,Zhou, Yu,Wang, Jun
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p. 5725 - 5735
(2019/10/23)
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- Aromatic Donor-Acceptor Interaction-Based Co(III)-salen Self-Assemblies and Their Applications in Asymmetric Ring Opening of Epoxides
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Aromatic donor-acceptor interaction as the driving force to assemble cooperative catalysts is described. Pyrene/naphthalenediimide functionalized Co(III)-salen complexes self-assembled into bimetallic catalysts through aromatic donor-acceptor interactions and showed high catalytic activity and selectivity in the asymmetric ring opening of various epoxides. Control experiments, nuclear magnetic resonance (NMR) spectroscopy titrations, mass spectrometry measurement, and X-ray crystal structure analysis confirmed that the catalysts assembled based on the aromatic donor-acceptor interaction, which can be a valuable noncovalent interaction in supramolecular catalyst development.
- Liang, Jian,Soucie, Luke N.,Blechschmidt, Daniel R.,Yoder, Aaron,Gustafson, Addie,Liu, Yu
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supporting information
p. 513 - 518
(2019/01/14)
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- Calix[8]arene as New Platform for Cobalt-Salen Complexes Immobilization and Use in Hydrolytic Kinetic Resolution of Epoxides
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Eight cobalt-salen complexes have been covalently attached to a calix[8]arene platform through a flexible linker by a procedure employing Click chemistry. The corresponding well-defined catalyst proved its efficiency in the hydrolytic kinetic resolution (HKR) of various epoxides through an operative bimetallic cooperative activation, demonstrating highly enhanced activity when compared to its monomeric analogue. As an insoluble complex, this multisite cobalt-salen catalyst could be easily recovered and reused in successive catalytic runs. Products were isolated by a simple filtration with virtually no cobalt traces and without requiring a prior purification by flash chromatography.
- Abdellah, Ibrahim,Martini, Cyril,Dos Santos, Amandine,Dragoe, Diana,Guérineau, Vincent,Huc, Vincent,Schulz, Emmanuelle
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p. 4761 - 4767
(2018/10/02)
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- Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes
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New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).
- Tak, Rajkumar,Kumar, Manish,Menapara, Tusharkumar,Gupta, Naveen,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Suresh
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supporting information
p. 3990 - 4001
(2017/11/22)
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- COMPOSITION CONTAINING ETHER LINKAGE-CONTAINING COMPOUND AND METHOD FOR PRODUCING THE SAME
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PROBLEM TO BE SOLVED: To provide a composition which can be used suitably as raw materials for a polymer having excellent water treatment performance and a method of producing the same. SOLUTION: The composition comprises a compound represented by a general formula (1), 0-20 mass% of a prescribed diol compound, 1-20 mass% of a prescribed compound having two carbon-carbon double bonds, and 0-1 mass% of a prescribed epoxy compound. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0078; 0079; 0084
(2017/09/14)
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- Synthesis method of allyl glyceroether
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The invention discloses a synthesis method of allyl glyceroether. The synthesis method comprises the following steps: taking allyl glycidyl ether as a raw material; carrying out hydrolysis ring-opening reaction under the action of a strong-acidity ion exchange resin supported SnCl4 catalyst; filtering and recycling a catalyst (capable of being circularly utilized); distilling to remove excessive amount of water; decompressing and rectifying to obtain a product, namely the allyl glyceroether, wherein the excessive amount of water recycled by distillation can be returned back and used as the raw material. According to the synthesis method disclosed by the invention, solid acid is used for catalyzing the allyl glycidyl ether to be subjected to ring opening with the water; compared with a traditional process, a process flow is short, reaction conditions are moderate and the operation is safe, simple and convenient; the raw material is easy to obtain and the yield of the product is high; the catalyst has low corrosiveness and can be recycled and circularly utilized, the process is clean and industrialization is prone to realize.
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Paragraph 0035; 0036
(2017/07/19)
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- Aniline-terephthalaldehyde resin p-toluenesulfonate (ATRT) as a highly efficient and reusable catalyst for alcoholysis, hydrolysis, and acetolysis of epoxides
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Alcoholysis, hydrolysis, and acetolysis of epoxides were carried out in the presence of a catalytic amount of aniline-terephthalaldehyde resin p-toluenesulfonate (ATRT) to give the corresponding β-substituted alcohols in good yields. Alcoholysis and hydrolysis of epoxides catalyzed by ATRT proceeded faster than those by pyridinium p-toluenesulfonate (PPTS).
- Tanemura, Kiyoshi,Suzuki, Tsuneo
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supporting information
p. 1781 - 1789
(2016/11/17)
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- A highly efficient protocol for regioselective ring-opening of epoxides with alcohols, water, acetic acid, and acetic anhydride catalyzed by SbF3
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SbF3as an efficient catalyst has been used for regioselective alcoholysis, acetolysis and hydrolysis of epoxides to the corresponding β-alkoxy, β-acetoxy alcohols, and 1,2-diols in high to excellent yields. This study also represents a convenient synthesis of vic-diacetates from ring-opening of epoxides with acetic anhydride.
- Zeynizadeh, Behzad,Gilanizadeh, Masumeh,Aminzadeh, Farkhondeh Mohammad
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p. 1051 - 1056
(2016/07/06)
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- COMPOSITION CONTAINING SULFONIC CID GROUP-CONTAINING ETHER COMPOUND AND MANUFACTURING METHOD THEREOF
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PROBLEM TO BE SOLVED: To provide a composition containing a sulfonic acid group-containing ether compound small in the content of a diol body, for example 3-allyloxy-1,2-dihydroxy propane as a by-product, the residual amount of a sulfite compound and the residual amount of allyl glycidyl ether, and a manufacturing method of the composition containing the sulfonic acid group-containing ether compound small in generation of a diol body, for example 3-allyloxy-1,2-dihydroxy propane as a by-product, the residual amount of a sulfite compound and the residual amount of allyl glycidyl ether at a high yield. SOLUTION: There is provided a composition containing a sulfonic acid group-containing ether compound represented by a specific general formula, a sulfite compound of 2000 ppm to 8000 ppm and an ether compound having 2 or more hydroxyl groups of 1.4 mass% to 3.5 mass%. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0072
(2018/10/31)
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- Selective functionalization of the primary hydroxy group in triols
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A procedure was suggested for preparing functionally substituted 1,2-diols by O-alkylation of hydroxyalkyl-1,3-dioxacyclanes with alkyl halides, followed by acid hydrolysis. The conditions for selective cleavage of the ethers obtained were found. (2,2-Dimethyl-1,3-dioxolan-4-yl)methyl benzoate under the conditions of acid deacetalization undergoes saponification of the ester group.
- Raskil'Dina,Valiev,Sultanova,Zlotskii
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p. 1599 - 1604
(2016/02/18)
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- Heterobimetallic dual-catalyst systems for the hydrolytic kinetic resolution of terminal epoxides
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A heterobimetallic dual-catalyst system based on the preparation and use of various salen complexes has been developed for the hydrolytic kinetic resolution (HKR) of terminal epoxides. A combination of cobalt-salen and manganese-salen complexes, generated from ligands with the same configuration possessing thiophene or pyrrole moieties, produced indeed highly selective catalysts for the hydrolysis of epibromohydrin. This effect could also be extended to other terminal epoxides and to the more challenging ring opening of cyclohexene oxide. Kinetic studies indicated that only one CoIII salen complex was involved in the rate-determining step, which supported a heterobimetallic highly enantioselective pathway based on the crucial existence of in situ generated CoIII-OH species, previously postulated in the literature. The beneficial effect of the presence of additional Mn-complexes was ascribed to the inhibition of the alternative less enantioselective monometallic reaction pathway by epoxide activation.
- Hong, Xiang,Mellah, Mohamed,Schulz, Emmanuelle
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p. 2608 - 2617
(2014/07/22)
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- A broadly applicable and practical oligomeric (salen)Co catalyst for enantioselective epoxide ring-opening reactions
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The (salen)Co catalyst (4a) can be prepared as a mixture of cyclic oligomers in a short, chromatography-free synthesis from inexpensive, commercially available precursors. This catalyst displays remarkable enhancements in reactivity and enantioselectivity relative to monomeric and other multimeric (salen)Co catalysts in a wide variety of enantioselective epoxide ring-opening reactions. The application of catalyst 4a is illustrated in the kinetic resolution of terminal epoxides by nucleophilic ring-opening with water, phenols, and primary alcohols; the desymmetrization of meso epoxides by addition of water and carbamates; and the desymmetrization of oxetanes by intramolecular ring opening with alcohols and phenols. The favorable solubility properties of complex 4a under the catalytic conditions facilitated mechanistic studies, allowing elucidation of the basis for the beneficial effect of oligomerization. Finally, a catalyst selection guide is provided to delineate the specific advantages of oligomeric catalyst 4a relative to (salen)Co monomer 1 for each reaction class.
- White, David E.,Tadross, Pamela M.,Lu, Zhe,Jacobsen, Eric N.
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p. 4165 - 4180
(2014/06/09)
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- Synthesis and biological activity of phosphoglycolipids from Thermus thermophilus
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An extreme thermophile, Thermus thermophilus, has very unique glycolipids on the cell surface. The acidic immunostimulatory phosphoglycolipid of T. thermophilus was synthesized for the first time, with newly developed glycosylation methods using 3-nitropyridyl (3NPy) and 4,6-dimethoxy-1,3,5- triazin-2-yl (DMT) glycosides as glycosyl donors. The analogues of the phosphoglycolipid, which include a diastereomer possessing the opposite configuration at the diacyl glycerol moiety, were also synthesized. The biological activities of the synthesized compounds were elucidated with cytokine inductions (IL-6 and TNF-α). A synthetic phosphoglycolipid with a natural-type diacyl glycerol configuration showed apparent immunostimulatory activity, whereas its diastereomer did not. The present study revealed that the configuration at the diacyl glycerol moiety of the phosphoglycolipids is important for immunostimulation, suggesting the existence of the particular receptor/recognizing protein that can recognize the stereochemistry of the glycerol part.
- Fujimoto, Yukari,Mitsunobe, Kunihiro,Fujiwara, Satoko,Mori, Motoko,Hashimoto, Masahiro,Suda, Yasuo,Kusumoto, Shoichi,Fukase, Koichi
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supporting information
p. 5034 - 5041
(2013/08/23)
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- METHODS FOR THE SYNTHESIS OF PLASMALOGENS AND PLASMALOGEN DERIVATIVES, AND THERAPEUTIC USES THEREOF
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A method for preparing plasmalogens and derivatives thereof represented by Formula B, wherein R1 and R2 are similar or different, derived from fatty acids; R3 is selected from hydrogen and small alkyl groups. The synthetic route involves production of novel cyclic plasmalogen precursors of Formula A and their conversion to plasmalogens and plasmalogen derivatives of Formula B. Also disclosed is the therapeutic use of plasmalogens and derivatives thereof as produced by the synthetic route of the present invention.
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Page/Page column 27-28
(2013/06/05)
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- Pd-catalyzed reaction of allyl carbonate with polyols: The role of CO 2 in transesterification versus etherification of glycerol
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An intermolecular Pd/PPh3-catalyzed transesterification of diallyl carbonate with glycerol to generate glycerol carbonate has been developed. Analysis of the reaction kinetics in THF indicates a first-order dependence on Pd and diallyl carbonate, that the Pd bears two phosphines during the turnover limiting event, and that increasing the glycerol concentration inhibits reaction, possibly via change in the polarity of the medium. 13C isotopic labeling studies demonstrate that the Pd-catalyzed transesterification requires at least one allyl carbonate moiety and that there is rapid equilibrium of the allyl carbonate with CO2 in solution, even when present only at low concentrations. A mechanism that is consistent with these results involves oxidative addition of the allyl carbonate to Pd followed by reversible decarboxylation, with the intermediate I·1- and I·3-allyl Pd alkoxides mediating direct and indirect transesterification reactions with the glycerol. Using this model, successful simulations of the kinetics of reactions conducted under atmospheres of N2 or CO2 could be achieved, including switching in selectivity between etherification and transesterification in the early stages of reaction. Reactions with the higher polyols threitol and erythritol are also efficient, generating the terminal (1,2) monocarbonates with high selectivity. It's a gas: A Pd-catalyzed transesterification of diallyl carbonate with polyols has been developed. The CO2 concentration is shown to control the relative rates of etherification and transesterification. Kinetic and isotopic labeling studies suggest that intermediate I·1-allyl Pd alkoxides mediate indirect intermolecular transesterification. The higher polyols erythritol and threitol selectively generate monocarbonates. Copyright
- Gordillo, Alvaro,Lloyd-Jones, Guy C.
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supporting information; scheme or table
p. 2660 - 2665
(2012/04/11)
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- Model studies toward a synthesis of asperaculin A: Exploration of iterative intramolecular Pauson-Khand reaction based strategies to access the dioxa[5.5.5.6]fenestrane framework
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A concise strategy, involving tandem intramolecular Pauson-Khand reactions (IPKRs) on a readily available ene-diyne precursor, to access the dioxa-fenestrane framework is delineated.
- Mehta, Goverdhan,Khan, Tabrez Babu
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scheme or table
p. 4558 - 4561
(2012/09/25)
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- Enzymatic synthesis of both enantiomeric forms of 3-allyloxy-propane-1,2- diol
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The stereoselective synthesis of (S)- and (R)-3-allyloxy-propane-1,2-diol has been accomplished in four steps from (RS)-3-allyloxy-propane-1,2-diol. Only one intermediate, namely 1-benzoyloxy-3-allyloxy-2-propanone has been prepared by a chemical reaction, that is, pyridinium chlorochromate oxidation of 1-benzoyloxy-3-allyloxypropan-2-ol. All of the remaining reactions (regioselective acylations, asymmetric bioreduction of prochiral ketones, and enzymatic alcoholysis) have been carried out in the presence of biocatalysts.
- Casati, Silvana,Santaniello, Enzo,Ciuffreda, Pierangela
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p. 395 - 400
(2012/07/14)
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- MANUFACTURING METHOD FOR SULFONIC ACID GROUP-CONTAINING ETHER COMPOUND
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The present invention provides a method for efficiently producing a sulfonic acid group-containing ether compound having a high purity and a good polymerizability while preventing production of a byproduct, and provides a sulfonic acid group-containing ether compound containing fewer impurities and having a good radical (co)polymerizability. The present invention provides a method of producing a sulfonic acid group-containing ether compound by reacting a sulfurous acid compound with a compound represented by the formula (1) : wherein R1 represents a single bond, a CH2 group, or a CH2-CH2 group, and R2 represents H, or a CH3 group, the method comprising the steps of: adjusting pH of a reaction system to 5.5 or grater with use of an alkaline substance; and adding the compound represented by the formula (1) to a reaction vessel containing the sulfurous acid compound.
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Page/Page column 10
(2011/06/23)
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- Investigation of the catalytic activity of an electron-deficient vanadium(IV) tetraphenylporphyrin: A new, highly efficient and reusable catalyst for ring-opening of epoxides
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In this work, the catalytic activity of high-valent tetraphenylporphyrinatovanadium(IV) trifluoromethanesulfonate, [V IV(TPP)(OTf)2], in the nucleophilic ring-opening of epoxides is reported. This new V(IV) catalyst was used as an efficient catalyst for alcoholysis with primary (methanol, ethanol and n-propanol), secondary (iso-propanol) and tertiary alcohols (tert-butanol), hydrolysis and acetolysis of epoxides with acetic acid and also for the conversion of epoxides to 1,2-diacetates with acetic anhydride, conversion of epoxides to thiiranes with ammonium thiocyanate and thiourea, and for conversion of epoxides to acetonides with acetone. The catalyst was reused several times without loss of its activity.
- Taghavi, S. Abdolmanaf,Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza,Ahmadi, Venus
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experimental part
p. 2244 - 2252
(2011/10/03)
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- Shell cross-linked micelle-based nanoreactors for the substrate-selective hydrolytic kinetic resolution of epoxides
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Shell cross-linked micelles (SCMs) containing Co(III)-salen cores were prepared from amphiphilic poly(2-oxazoline) triblock copolymers. The catalytic activity of these nanoreactors for the hydrolytic kinetic resolution of various terminal epoxides was investigated. The SCM catalysts showed high catalytic efficiency and, more significantly, substrate selectivity based on the hydrophobic nature of the epoxide. Moreover, because of the nanoscale particle size and the high stability, the catalyst could be recovered easily by ultrafiltration and reused with high activity for eight cycles.
- Liu, Yu,Wang, Yu,Wang, Yufeng,Lu, Jie,Pinon, Victor,Weck, Marcus
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supporting information; experimental part
p. 14260 - 14263
(2011/11/05)
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- MCM-41 grafted quaternary ammonium salts as recyclable catalysts for the sequential synthesis of dimethyl carbonate from epoxides, CO2, and methanol
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One kind of novel heterogenous bifunctional catalyst, MCM- 41 grafted quaternary ammonium salts with terminal amino group, was prepared. These catalysts exhibited excellent catalytic performance and good reusability in the sequential synthesis of dimethyl carbonate from epoxides, CO2, and methanol.
- Li, Jian,Wang, Liguo,Liu, Shimin,Li, Xueli,Shi, Feng,Deng, Youquan
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supporting information; experimental part
p. 1277 - 1278
(2011/02/17)
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- An environmentally benign catalytic method for efficient and selective nucleophilic ring opening of oxiranes by zirconium tetrakis(dodecyl Sulfate)
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An operationally simple and environmentally benign protocol for a highly regio- and chemoselective preparation of β-substituted alcohols by means of ring-opening reactions of oxiranes with various aliphatic alcohols, H 2O, NaN3 , and NaCN as nucleophiles in the presence of catalytic amounts of zirconium tetrakis(dodecyl sulfate) as Lewis acid/surfactant-combined catalysts (LASCs) was developed. The high efficiency of the catalyst was confirmed by the high product yields obtained within desired times and, in particularly by the reusability of the ZrIV complex.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Aliabadi, Marzieh
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scheme or table
p. 405 - 413
(2010/05/19)
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- Erbium(III) triflate is a highly efficient catalyst for the synthesis of β-alkoxy alcohols, 1,2-diols and β-hydroxy sulfides by ring opening of epoxides
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Chemo- and stereoselectivity in the ring-opening reaction of epoxides with erbium(III) triflate are described. Epoxides can be cleaved under neutral conditions with alcohols and thiols in the presence of catalytic amounts of Lewis acid, affording the corresponding β-alkoxy alcohols and β-hydroxy sulfides in high yields. In water, epoxide ring opening occurs to produce the corresponding diols in good yields.
- Dalpozzo, Renato,Nardi, Monica,Oliverio, Manuela,Paonessa, Rosina,Procopio, Antonio
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experimental part
p. 3433 - 3438
(2010/02/28)
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- Engineering polymer-enhanced bimetallic cooperative interactions in the hydrolytic kinetic resolution of epoxides
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Through systematic variations of the length of oligo(ethylene glycol)-based linkers and the catalyst density of poly(styrene)-supported cobalt-salen catalysts, we have elucidated an optimal catalyst flexibility and density of polymeric Co-salen catalysts for the hydrolytic kinetic resolution (HKR) of racemic terminal epoxides that follows a bimetallic cooperative pathway. The optimized polymeric catalyst brings the two cooperative Co-salen units to a favorable proximity efficiently and hence displays significantly improved catalytic performance in the HKR compared with its monomeric small molecule analogue. Complex Co(5b), representing the most active poly(styrene)-supported HKR catalyst known so far, can effect the resolution of a variety of epoxides to reach ≥ 98 % ee in 6-24 h with a low cobalt loading of 0.01-0.1 mol%.
- Zheng, Xiaolai,Jones, Christopher W.,Weck, Marcus
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supporting information; experimental part
p. 255 - 261
(2009/04/08)
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- Enhanced cooperativity in hydrolytic kinetic resolution of epoxides using poly(styrene) resin-supported dendronized co-(salen) catalysts
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Excellent enantioselectivities and isolated yields have been achieved for the hydrolytic kinetic resolution of epoxides using a resin-supported dendronized R,R-(salen)Co catalyst with catalyst loadings as low as 0.04 mol%, the lowest metal loadings of any heterogeneous resin-supported (salen)Co catalyst reported to date. In addition, the supported catalysts can be recycled and reused with comparable enantioselectivities. It is hypothesized that the high catalytic activity can be attributed to the flexible linker and the dendronized framework supporting the (salen)Co moieties on the resin thereby promoting cooperativity between two metal centers. This work opens up new opportunities for the design of highly active resin-supported catalysts that catalyze transformations through a bimetallic pathway.
- Goyal, Poorva,Zheng, Xiaolai,Weck, Marcus
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experimental part
p. 1816 - 1822
(2009/08/07)
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- Ring-expanding olefin metathesis: A route to highly active unsymmetrical macrocyclic oligomeric co-salen catalysts for the hydrolytic kinetic resolution of epoxides
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In the presence of the third generation Grubbs catalyst, the ring-expanding olefin metathesis of a monocyclooct-4-en-1-yl functionalized salen ligand and the corresponding Co(II)(salen) complex at low monomer concentrations results in the exclusive formation of macrocyclic oligomeric structures with the salen moieties being attached in an unsymmetrical, flexible, pendent manner. The TOF-MALDI mass spectrometry reveals that the resulting macrocyclic oligomers consist predominantly of dimeric to tetrameric species, with detectable traces of higher homologues up to a decamer. Upon activation under aerobic and acidic conditions, these Co(salen) macrocycles exhibit extremely high reactivities and selectivities in the hydrolytic kinetic resolution (HKR) of a variety of racemic terminal epoxides under neat conditions with very low catalyst loadings. The excellent catalytic properties can be explained in terms of the new catalyst's appealing structural features, namely, the flexible oligomer backbone, the unsymmetrical pendent immobilization motif of the catalytic sites, and the high local concentration of Co(salen) species resulting from the macrocyclic framework. This ring-expanding olefin metathesis is suggested to be a simple way to prepare tethered metal complexes that are endowed with key features - (i) a high local concentration of metal complexes and (ii) a flexible, single point of attachment to the support - that facilitate rapid and efficient catalysis when a bimetallic transition state is required.
- Zheng, Xiaolai,Jones, Christopher W.,Weck, Marcus
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p. 1105 - 1112
(2007/10/03)
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- Synthesis of structural variants of Staphylococcus aureus lipoteichoic acid (LTA)
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Based on 1,2-O-isopropylidene-sn-glycerol, which is readily available from d-mannitol, five chiral building blocks for the construction of structural variants of Staphylococcus aureus LTA designed and synthesized. Ligation of these building blocks led readily to the target molecules 1 and 2. They demonstrated that the d-alanine residues at the glycerophosphate backbone are decisive for the activation of the immune system.
- Figueroa-Perez, Ignacio,Stadelmaier, Andreas,Morath, Siegfried,Hartung, Thomas,Schmidt, Richard R.
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p. 493 - 506
(2007/10/03)
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- Rapid and efficient ring opening of epoxides catalyzed by a new electron deficient tin(IV) porphyrin
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The new electron deficient tin(IV) tetraphenylporphyrinato trifluoromethanesulfonate, [SnIV(tpp)(OTf)2], was used as an efficient catalyst for the alcoholysis, hydrolysis and acetolysis of epoxides. Conversion of epoxides to thiiranes and acetonides were also performed efficiently in the presence of this catalyst.
- Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Shaibani, Reza
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p. 6105 - 6111
(2007/10/03)
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- Silica sulfuric acid; an efficient and reusable catalyst for regioselective ring opening of epoxides by alcohols and water
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The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of silica sulfuric acid with high degree of regioselectivity. The catalyst is reusable and can be applied several times without any decrease in the yield of reactions.
- Salehi, Peyman,Dabiri, Minoo,Zolfigol, Mohammad Ali,Fard, Mohammad Ali Bodaghi
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p. 1113 - 1121
(2007/10/03)
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- Direct synthesis of plasmenylcholine from allyl-substituted glycerols
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We report a new method for the facile preparation of plasmenylcholine via reaction of lithioalkoxy allyl intermediates with 1-iodoalkanes as the key step in the stereoselective formation of 1′-(Z)-alkenyl glyceryl ethers. The allyl anion intermediate is prepared by treating mono- or disiloxy-protected 1-allylglycerol precursors with s-BuLi at -65 to -80°C. Subsequent addition of 1-iodoalkane solutions at low temperature gives moderate yields of γ-coupled, Z-vinyl ethers as the major product and α-coupled product as the minor component. Several different preparative strategies for the total synthesis of plasmalogens are enabled by this simple transformation.
- Shin, Junhwa,Thompson, David H.
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p. 6760 - 6766
(2007/10/03)
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- Magnesium hydrogensulfate: A cheap and efficient catalyst for the conversion of epoxides into β-alkoxy alcohols, vicinal-diols, and thiiranes
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The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of magnesium hydrogensulfate, Mg(HSO4)2, with high degree of regioselectivity. The reactions are chemoselective and many of the other functional groups such as ethereal carbon oxygen bonds as well as carbon-carbon double bond remain intact under the reaction conditions. Epoxides also react with thiourea or ammonium thiocyanate in the presence of Mg(HSO 4)2 to afford the corresponding thiiranes in good to excellent yields.
- Salehi, Peyman,Khodaei, Mohammad Mahdi,Zolfigol, Mohammad Ali,Keyvan, Afsaneh
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p. 3041 - 3048
(2007/10/03)
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- Efficient regio- and stereoselective ring opening of epoxides with alcohols, acetic acid and water catalyzed by ammonium decatungstocerate(IV)
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Epoxides can be cleaved in a regio- and stereoselective manner under neutral conditions with alcohols and acetic acid in the presence of catalytic amounts of decatungstocerate(IV) ion, ([CeW10O36] 8-), affording the corresponding β-alkoxy and β-acetoxy alcohols in high yields. In water, ring opening of epoxides occurs with this catalyst to produce the corresponding diols in good yields.
- Mirkhani, Valiollah,Tangestaninejad, Shahram,Yadollahi, Bahram,Alipanah, Ladan
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p. 8213 - 8218
(2007/10/03)
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- 2,2'-Bipyridine lariat calixcrowns: A new class of encapsulating ligands forming highly luminescent Eu3+ and Tb 3+ complexes
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A new class of calix[4]arene crown ethers with one or two bipyridines appended to the polyether ring (lariat calixcrowns) have been designed and synthesized; the luminescence properties of their Eu3+ and Tb3+ complexes have been studied in acetonitrile. In this solvent, long lifetimes for the metal emitting states and high metal-luminescence intensities obtained upon ligand excitation have been observed in both Eu3+ and Tb3+ complexes. The association constants in methanol have been determined for some of the complexes studied.
- Fischer, Claudia,Sarti, Gianluca,Casnati, Alessandro,Carrettoni, Barbara,Manet, Ilse,Schuurman, Ruud,Guardigli, Massimo,Sabbatini, Nanda,Ungaro, Rocco
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p. 1026 - 1034
(2007/10/03)
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- Bismuth(III) chloride (BiCl3); an efficient catalyst for mild, regio- and stereoselective cleavage of epoxides with alcohols, acetic acid and water
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Epoxides can be cleaved in a regio- and stereoselective manner with alcohols, acetic acid and water in the presence of catalytic amounts of bismuth(III) chloride, affording the corresponding β-alkoxy and β-acetoxy alcohols and diols in high yields.
- Mohammadpoor-Baltork,Tangestaninejad,Aliyan,Mirkhani
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p. 2365 - 2374
(2007/10/03)
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- Iron(III) trifluoroacetate as an efficient catalyst for solvolytic and nonsolvolytic nucleophilic ring opening of epoxides
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Iron(III) trifluoroacetate was used as an efficient and nonhygroscopic catalyst for the alcoholysis, hydrolysis, and acetolysis of epoxides. The addition of chloride, bromide, iodide, and nitrate ions to epoxides to produce the corresponding 2-halo and 2-nitratoalkanols and also the conversion of epoxides to acetonides and thiiranes were also performed efficiently in the presence of this catalyst.
- Iranpoor, Nasser,Adibi, Hadi
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p. 675 - 680
(2007/10/03)
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- Hydroxynitrile lyase catalyzed enantioselective HCN addition to O-protected α-hydroxyaldehydes
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Various O-protected glycol- and racemic lactaldehydes 3 and 6 as well as O-allyl protected racemic α-hydroxyaldehydes 7 (R1=Et, Pr, Bu) have been prepared to investigate and perform a stereoselective Kiliani-Fischer synthesis by hydroxynitrile lyase (HNL) catalyzed addition of HCN. From all protecting groups investigated the allyl moiety was most suitable. (R)-PaHNL from bitter almonds (Prunus amygdalus), yielding the (2S)-cyanohydrins 8-10, was found to be a more stereoselective catalyst than (S)-MeHNL from maniok (Manihot esculenta). While (R)-PaHNL led to enantiomeric excesses ≥93%, with (S)-MeHNL the (2R)-cyanohydrins 8-10 were obtained with enantiomeric excesses ≤78%.
- Roos, Juergen,Effenberger, Franz
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p. 2817 - 2828
(2007/10/03)
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- TiCl3(OTf) and TiO(TFA)2 efficient catalysts for ring opening of epoxides with alcohols, acetic acid and water
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TiCl3 (OTf) and TiO(TFA)2 can efficiently catalyze nucleophilic ring opening of epoxides in primary, secondary and tertiary alcohols, acetic acid and water to give the corresponding β-alkoxy alcohols, β-acetoxy alcohols and vicinal diols with high stereo- and regioselectivity in excellent yields. The reaction of optically active styrene oxide in MeOH with two titanium reagents was found to be highly stereospecific and afforded the corresponding S-(+)-2-methoxy-2-phenyl ethanol in 89-95% ee.
- Iranpoor, Nasser,Zeynizadeh, Behzad
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p. 1017 - 1024
(2007/10/03)
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- Symmetry-Assisted Synthesis of C2-Symmetric trans-α,α'-Bis(hydroxymethyl)pyrrolidine and -piperidine Derivatives via Double Sharpless Asymmetric Dihydroxylation of αω-Terminal Dienes
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A new strategy has been developed for the synthesis of C2-symmetric trans-α,α'-bis(hydroxymethyl)pyrrolidine and piperidine derivatives 1-3 starting from symmetric αω-terminal dienes 4-6. The double-asymmetric dihydroxylation (AD) reaction of 4-6 gave C2-symmetric tetrols, which were converted in a four-step sequence to C2-symmetric azacycloalkanes 17,9, and 22, respectively. These azacycloalkanes were transformed into 1-3 in high enantiomeric excess (82% → 98%ee). The double AD reaction proved to cause enantiomeric enhancement, even though the asymmetric induction for the first AD reaction is moderate. In addition, it was observed that the chromatography on silica gel of several C2-symmetric azacycloalkanes (17, 20, and 22) of varying ee's resulted in marked enantiomeric fractionation.
- Takahata, Hiroki,Takahashi, Seiki,Kouno, Shin-Ichi,Momose, Takefumi
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p. 2224 - 2231
(2007/10/03)
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