- 3-(Acyloxy)propanolamines: agents with β-adrenergic blocking activity
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A series of totally aliphatic 3-(acyloxy)propanolamine derivatives were prepared and their pA2-values were determined employing the guinea-pig atrium.Compounds, with an acetyl or methyl succinoyl half ester moiety showed a pronounced β1-adrenergic blocking activity.Keywords: 3-(acyloxy)propanolamines / β1-adrenergic blocking activity
- Leuschner, J.,Schaefer, H.,Leuschner, F.
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- Highly selective and efficient olefin epoxidation with pure inorganic-ligand supported iron catalysts
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Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.
- Zhou, Zhuohong,Dai, Guoyong,Ru, Shi,Yu, Han,Wei, Yongge
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supporting information
p. 14201 - 14205
(2019/10/02)
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- Poly(Alkyl Glycidate Carbonate)s as Degradable Pressure-Sensitive Adhesives
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Insertion of CO2 into the polyacrylate backbone, forming poly(carbonate) analogues, provides an environmentally friendly and biocompatible alternative. The synthesis of five poly(carbonate) analogues of poly(methyl acrylate), poly(ethyl acrylate), and poly(butyl acrylate) is described. The polymers are prepared using the salen cobalt(III) complex catalyzed copolymerization of CO2 and a derivatized oxirane. All the carbonate analogues possess higher glass-transition temperatures (Tg=32 to ?5 °C) than alkyl acrylates (Tg=10 to ?50 °C), however, the carbonate analogues (Td≈230 °C) undergo thermal decomposition at lower temperatures than their acrylate counterparts (Td≈380 °C). The poly(alkyl carbonates) exhibit compositional-dependent adhesivity. The poly(carbonate) analogues degrade into glycerol, alcohol, and CO2 in a time- and pH-dependent manner with the rate of degradation accelerated at higher pH conditions, in contrast to poly(acrylate)s.
- Beharaj, Anjeza,Ekladious, Iriny,Grinstaff, Mark W.
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supporting information
p. 1407 - 1411
(2019/01/14)
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- Continuous-Flow Synthesis of (R)-Propylene Carbonate: An Important Intermediate in the Synthesis of Tenofovir
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(R)-Propylene carbonate is an important intermediate in the synthesis of tenofovir pro-drugs such as tenofovir alafenamide fumarate (TAF) and tenofovir diisoproyl fumarate (TDF). Independent of the pro-drug type, tenofovir presents a chiral secondary hydroxy derivative, which can be obtained directly from (R)-propylene carbonate. Herein, we report our chemo-enzymatic continuous-flow strategy towards (R)-propylene carbonate starting from a very cheap and renewable raw material, glycerol. We were able to synthesize (R)-propylene carbonate in seven continuous-flow steps, starting from glycerol, in good-to-excellent yields (66–93 %) and excellent selectivity (E > 200).
- Suveges, Nicolas S.,Rodriguez, Anderson A.,Diederichs, Carla C.,de Souza, Stefania P.,Le?o, Raquel A. C.,Miranda, Leandro S. M.,Horta, Bruno A. C.,Pedraza, Sérgio F.,de Carvalho, Otavio V.,Pais, Karla C.,Terra, José H. C.,de Souza, Rodrigo O. M. A.
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supporting information
p. 2931 - 2938
(2018/06/27)
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- Synthesis and enzymatic resolution of racemic 2,3-epoxy propyl esters obtained from glycerol
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A method is described for the synthesis of (±)-2,3-epoxy propyl esters from glycerol, involving reaction of epichlorohydrin with sodium or potassium salts of carboxylic acids in the presence of TBAB as catalyst, with moderate to excellent yields. Kinetic resolution of glycidyl butyrate by lipase of Thermomyces lanuginosa has been achieved with remarkable enantiomeric excess (ee >99%) using 1,4-dioxane as a co-solvent in pure buffer solution (30 and 50 °C, pH = 7.0).
- Araujo, Yara Jaqueline Kerber,Avvari, Naga Prasad,Paiva, Derisvaldo Rosa,De Lima, Dênis Pires,Beatriz, Adilson
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supporting information
p. 1696 - 1698
(2015/03/14)
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- Composites of [γ-H2PV2W10O40]3- and [α-SiW12O40]4- supported on Fe2O3 as heterogeneous catalysts for selective oxidation with aqueous hydrogen peroxide
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Composites of [γ-H2PV2W10O40]3- and [α-SiW12O40]4- supported on Fe2O3 (PV2-SiW12/Fe2O3, in particular, the molar ratio of PV2/SiW12 = 1/1) could act as effective and reusable heterogeneous catalysts for selective oxidation with aqueous hydrogen peroxide. In the presence of PV2-SiW12/Fe2O3, various kinds of organic substrates such as alkenes, sulfides, arenes, and alkanes could selectively be converted into the corresponding oxygenated products in moderate to high yields. The observed catalyses for the present oxidations were intrinsically heterogeneous, and PV2-SiW12/Fe2O3 could be reused at least three times for each oxidation (epoxidation, sulfoxidation, and arene hydroxylation) without appreciable losses of the high catalytic performance.
- Wang, Ye,Kamata, Keigo,Ishimoto, Ryo,Ogasawara, Yoshiyuki,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 2602 - 2611
(2015/05/13)
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- A basic germanodecatungstate with a - 7 charge: Efficient chemoselective acylation of primary alcohols
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The synthesis of highly negatively charged polyoxometalates with electrically and structurally controlled uniform basic sites can lead to the unique base catalysis. In this work, a γ-Keggin germanodecatungstate, [γ-HGeW10O36]7- (A), having a -7 charge was, for the first time, successfully synthesized by the reaction of [γ-H2GeW10O36]6- with one equivalent of [(n-C4H9)4N]OH under non-aqueous conditions. The activities of germanodecatungstates for base-catalyzed reactions dramatically increased with increase in the number negative charges from -6 to -7. In the presence of A, various combinations of acylating agents and primary alcohols including those with acid-sensitive functional groups chemoselectively gave the desired acylated products in high yields even under the stoichiometric conditions.
- Sugahara, Kosei,Satake, Naoto,Kamata, Keigo,Nakajima, Takahito,Mizuno, Noritaka
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supporting information
p. 13248 - 13252
(2015/01/09)
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- Oxidative functional group transformations with hydrogen peroxide catalyzed by a divanadium-substituted phosphotungstate
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A divanadium-substituted phosphotungstate TBA4[γ-PW 10O38V2(μ-OH)(μ-O)] (I, TBA = tetra-n-butylammonium) reacts with one equivalent H+ to form a bis-μ-hydroxo species [γ-PW10O38V 2(μ-OH)2]3- (I′) in organic media. The strong electrophilic oxidants such as [γ-PW10O 38V2(μ-OH)(μ-OOH)]3- (II) and [γ-PW10O38V2(μ-η2: η2-O2)]3- (III) are formed by the reaction of the bis-μ-hydroxo species with H2O2. In the presence of I and H+, H2O2-based oxidations such as (i) epoxidation of alkenes (17 examples including electron-deficient ones), (ii) hydroxylation of alkanes (11 examples), and (iii) oxidative bromination of alkenes, alkynes, and aromatics with Br- as a bromo source (12 examples including chlorination) chemo-, diastereo-, and regioselectively proceed to give the corresponding oxidized products in moderate to high yields with high efficiencies of H2O2 utilization.
- Mizuno, Noritaka,Kamata, Keigo,Yamaguchi, Kazuya
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scheme or table
p. 157 - 161
(2012/06/18)
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- Efficient epoxidation of electron-deficient alkenes with hydrogen peroxide catalyzed by [γ-PW10O38V2(μ-OH) 2]3-
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A divanadium-substituted phosphotungstate, [γ-PW10O 38V2(μ-OH)2]3- (I), showed the highest catalytic activity for the H2O2-based epoxidation of allyl acetate among vanadium and tungsten complexes with a turnover number of 210. In the presence of I, various kinds of electron-deficient alkenes with acetate, ether, carbonyl, and chloro groups at the allylic positions could chemoselectively be oxidized to the corresponding epoxides in high yields with only an equimolar amount of H2O2 with respect to the substrates. Even acrylonitrile and methacrylonitrile could be epoxidized without formation of the corresponding amides. In addition, I could rapidly (min) catalyze epoxidation of various kinds of terminal, internal, and cyclic alkenes with H;bsubesubbsubesub& under the stoichiometric conditions. The mechanistic, spectroscopic, and kinetic studies showed that the I-catalyzed epoxidation consists of the following three steps: 1) The reaction of I with H;bsubesubbsubesub& leads to reversible formation of a hydroperoxo species [I;circbsubesubbsubesubbsubesubcirccircbsupesup& (II), 2) the successive dehydration of II forms an active oxygen species with a peroxo group [ 2:2-O2)]3- (III), and 3) III reacts with alkene to form the corresponding epoxide. The kinetic studies showed that the present epoxidation proceeds via III. Catalytic activities of divanadium-substituted polyoxotungstates for epoxidation with H 2O2 were dependent on the different kinds of the heteroatoms (i.e., Si or P) in the catalyst and I was more active than [γ-SiW10O38V2(μ-OH)2] 4-. On the basis of the kinetic, spectroscopic, and computational results, including those of [γ-SiW10O38V 2(μ-OH)2]4-, the acidity of the hydroperoxo species in II would play an important role in the dehydration reactivity (i.e., k3). The largest k3 value of I leads to a significant increase in the catalytic activity of I under the more concentrated conditions. Copyright
- Kamata, Keigo,Sugahara, Kosei,Yonehara, Kazuhiro,Ishimoto, Ryo,Mizuno, Noritaka
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scheme or table
p. 7549 - 7559
(2011/08/03)
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- MANUFACTURE OF AN EPOXYETHYL CARBOXYLATE OR GLYCIDYL CARBOXYLATE
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The invention relates to a process for the manufacture of an epoxyethyl carboxylate or glycidyl carboxylate, including reacting a vinyl carboxylate or an allyl carboxylate using an oxidant and a water-soluble manganese complex in an aqueous reaction medium, and the water-soluble manganese complex comprises an oxidation catalyst, characterized in that the water-soluble manganese complex is a mononuclear species of the general formula (I): [LMnX3]Y, or a binuclear species of the general formula (II): [LMn(μ-X)3MnL]Yn, wherein Mn is a manganese; L is a ligand and each L is independently a polydentate ligand, each X is independently a coordinating species and each μ-X is independently a bridging coordinating species, Y is a non-coordinating counter ion, and wherein the epoxidation is carried out at a pH in the range of from 1.0 to 7.0.
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Page/Page column 14-15
(2011/09/14)
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- Process for the manufacture of a 1,2-Epoxide
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The invention relates to a process for the manufacture of a 1,2-epoxide by catalytic oxidation of a terminal olefin with hydrogen peroxide wherein the catalytic oxidation is performed in a biphasic system comprising an organic phase and an aqueous reaction medium, wherein a water-soluble manganese complex is used as oxidation catalyst, wherein a terminal olefin is used with a solubility at 20°C of at least 0,01 to 100 g in 1 liter water, and wherein the molar ratio of terminal olefin to hydrogen peroxide is in the range of from 1:0.1 to 1:2.
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Page/Page column 7
(2010/03/02)
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- Covalent heterogenization of a discrete Mn(II) Bis-Phen complex by a metal-template/metal-exchange method: An epoxidation catalyst with enhanced reactivity
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Considerable attention has been devoted to the immobilization of discrete epoxidation catalysts onto solid supports due to the possible benefits of site isolation such as increased catalyst stability, catalyst recycling, and product separation. A synthetic metal-template/metal-exchange method to imprint a covalently attached bis-1,10-phenanthroline coordination environment onto high-surface area, mesoporous SBA-15 silica is reported herein along with the epoxidation reactivity once reloaded with manganese. Comparisons of this imprinted material with material synthesized by random grafting of the ligand show that the template method creates more reproducible, solution-like bis-1,10-phenanthroline coordination at a variety of ligand loadings. Olefin epoxidation with peracetic acid shows the imprinted manganese catalysts have improved product selectivity for epoxides, greater substrate scope, more efficient use of oxidant, and higher reactivity than their homogeneous or grafted analogues independent of ligand loading. The randomly grafted manganese catalysts, however, show reactivity that varies with ligand loading while the homogeneous analogue degrades trisubstituted olefins and produces trans-epoxide products from cis-olefins. Efficient recycling behavior of the templated catalysts is also possible.
- Terry, Tracy J.,Daniel,Stack
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p. 4945 - 4953
(2008/09/21)
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- Regioselectivity and diasteroselectivity in Pt(II)-mediated "green" catalytic epoxidation of terminal alkenes with hydrogen peroxide: Mechanistic insight into a peculiar substrate selectivity
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Recently developed electron-poor Pt(II) catalyst 1 with the "green" oxidant 35% hydrogen peroxide displays high activity and complete substrate selectivity in the epoxidation of terminal alkenes because of stringent steric and electronic requirements. In the presence of isolated dienes bearing terminal and internal double bonds, epoxidation is completely regioselective toward the production of terminal epoxides. Insight into the mechanism is gained by means of a reaction progress kinetic analysis approach that underlines the peculiar role of 1 in activating both the alkene and H 2O2 in the rate-determining step providing a rare example of nucleophilic oxidation of alkenes by H2O2.
- Colladon, Marco,Scarso, Alessandro,Sgarbossa, Paolo,Michelin, Rino A.,Strukul, Giorgio
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p. 7680 - 7689
(2008/02/05)
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- Trimanganese complexes bearing bidentate nitrogen ligands as a highly efficient catalyst precursor in the epoxidation of alkenes
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A series of trinuclear manganese complexes coordinated with neutral bidentate nitrogen ligands, [Mn3L2-(OAc)6], were prepared from manganese acetate and the corresponding ligands. Using peracetic acid as the oxidant, the air- and moisture-stable manganese clusters exhibited excellent catalytic activity and selectivity in the epoxidation of olefins under mild conditions. The highest activity was observed with a trinuclear complex containing a 2-pyridylimino ligand, [Mn3(ppei) 2(OAc)6] (ppei = 2-pyridinal-1-phenylethylimine). With this system, the substrate scope was extremely wide to include terminal and electron-deficient double bonds of both aliphatic and aromatic alkenes. The high activity was undiminished under the reaction conditions even directly using a mixture of the pyridylimino ligands and manganese acetates, making this process more convenient. It was also observed that analogous trinuclear complexes, such as [Mn3(bipy)2(OAc)6] and [Mn 3(phen)2(OAc)6], displayed excellent activities. While radical intermediacy was inferred from the product distribution, kinetic data revealed that the epoxidation is roughly first-order in manganese cluster precursor and oxidant, respectively, and zero-order in olefin. These results led us to propose that the trinuclear complexes [Mn 3L2(OAc)6] serve as catalyst precursors that dissociate into monomeric species with the formulation of [MnL 2(OAc)2] under the reaction conditions.
- Kang, Byungman,Kim, Min,Lee, Junseong,Do, Youngkyu,Chang, Sukbok
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p. 6721 - 6727
(2007/10/03)
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- Catalyst-free gas-phase epoxidation of alkenes
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Butadiene, styrene, cyclohexene, allyl acetate, methyl methacrylate, and allyl alcohol were epoxidized in a gas-phase reaction in the absence of a catalyst. The applied oxidizing agent is ozone. With exception of allyl alcohol (selectivity to glycidol: 58%), the selectivity to the corresponding epoxide ranged from 88 to 97%. For acrylonitrile, there was no measureable conversion. Copyright
- Berndt, Torsten,Boege, Olaf
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p. 584 - 585
(2007/10/03)
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- Regioselective opening of an oxirane system with trifluoroacetic anhydride. A general method for the synthesis of 2-monoacyl- and 1,3-symmetrical triacylglycerols
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A trifluoroacetic anhydride-catalyzed opening of the oxirane system of glycidyl esters with a simultaneous migration of the acyl group provides a new, efficient entry to either 2-monoacylglycerols (2-MAG) or 1,3-symmetrical triglycerides (1,3-STG) as potential prodrug frameworks.
- Stamatov, Stephan D.,Stawinski, Jacek
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p. 3659 - 3669
(2007/10/03)
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- Efficient epoxidation of electron-deficient olefins with a cationic manganese complex
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The complex [MnII(R,R-mcp)(CF3SO3)2] is an efficient and practical catalyst for the epoxidation of electron-deficient olefins. This catalyst is capable of epoxidizing olefins with as little as 0.1 mol % catalyst in under 5 min using 1.2 equiv of peracetic acid as the terminal oxidant. A wide scope of substrates are epoxidized including terminal, tertiary, cis and trans internal, enones, and methacrylates with >85% isolated yields. Copyright
- Murphy, Andrew,Dubois, Geraud,Stack
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p. 5250 - 5251
(2007/10/03)
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- Novel synthesis and enzymatic resolution of (±)-2,3-epoxy propyl esters
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A novel method of synthesizing glycidyl esters (±) -2,3-epoxy propyl esters has been developed involving reaction of epichlorohydrin with sodium salt of carboxylic acids in the presence of 15-crown-5 as catalyst with excellent yields. Enzymatic resolution of these glycidyl esters by lipasePS- C has been achieved with remarkable substrate selectivity.
- Nair, Ranjeet V.,Patil, Prashant N.,Salunkhe, Manikrao M.
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p. 2559 - 2566
(2007/10/03)
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- Epoxidation of terminal or electron-deficient olefins with H2O2, catalysed by Mn-trimethyltriazacyclonane complexes in the presence of an oxalate buffer
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A catalytic amount of an oxalate/oxalic acid buffer strongly enhances the catalytic properties of Mn-tmtacn complexes for epoxidation reactions with H2O2. Especially terminal olefins are easily epoxidized. Yields for e.g. allyl acetate or 1-hexene reach up to 99 % and 65 % on olefin and peroxide basis respectively. The reaction is stereospecific; there are no products of solvolysis.
- De Vos, Dirk E.,Sels, Bert F.,Reynaers, Mattias,Subba Rao,Jacobs, Pierre A.
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p. 3221 - 3224
(2007/10/03)
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- The Synthesis of Oxiranes and Oxetanes from 1,2- or 1,3-Halohydrins Using Organoantimony(V) Alkoxide
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Tetraphenylstibonium methoxide (1) is an effictive reagent for the synthesis of oxiranes and oxetanes from the corresponding 1,2- and 1,3-halohydrins, respectively.As the reaction conditions are neutral, oxiranes bearing an ester moiety were obtained intact without undergoing solvolysis.In addition, oxetanes, whose preparation was not generally facile, were formed in good yields under mild conditions (60-80 deg C).
- Fujiwara, Masahiro,Hitomi, Kazuhisa,Baba, Akio,Matsuda, Haruo
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p. 106 - 109
(2007/10/02)
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- A Convenient Synthesis of Glycidyl Esters (2,3-Epoxypropyl Alkanoates)
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A novel method for synthesizing glycidyl esters (2,3-epoxypropyl alkanoates) 1 has been achieved by the sequence of the organotin phosphate catalyzed reaction of epichlorohydrin 2 with carboxylic acids and dehydrochlorination of the resulting mixture of ester chlorohydrins 3 + 4 followed by separation.
- Otera, Junzo,Matsuzaki, Shinjiro
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p. 1019 - 1020
(2007/10/02)
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- An Electron Spin Resonance Study of 3-Oxypropenoyl Radicals derived from Glycidols
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Glycidols with blocked OH groups (A; M = alkyl or trialkylsilyl) react with t-butoxyl radicals to show the e.s.r. spectra of the corresponding 3-oxypropenoyl radicals (D), and 24 examples of these acyl radicals are reported.The reaction is thought to proceed through the formation of the allyloxyl radicals (B), which, in part, are converted into the aldehyde (C) which is very reactive towards loss of hydrogen to give the acyl radical (D).Glycidyl pivalate (A; M = COCMe3) reacts cleanly in this way, but glycidyl acetate (E; R = Me) also undergoes intramolecular 1,5-transfer of the acyl group to show the spectrum of the enoxyl radical (F).Glycidyl propionate and butyrate do not undergo this acyl transfer, but show the spectra of the radicals and (R' = Me or Et).
- Davies, Alwyn G.,Hawari, Jalal A.-A.,Muggleton, Brenda,Tse, Man-Wing
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p. 1132 - 1137
(2007/10/02)
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