- A transesterification-acetalization catalytic tandem process for the functionalization of glycerol: The pivotal role of isopropenyl acetate
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At 30 °C, in the presence of Amberlyst-15 as a catalyst, a tandem sequence was implemented by which a pool of innocuous reactants (isopropenyl acetate, acetic acid and acetone) allowed upgrading of glycerol through selective acetylation and acetalization processes. The study provided evidence for the occurrence of multiple concomitant reactions. Isopropenyl acetate acted as a transesterification agent to provide glyceryl esters, and it was concurrently subjected to an acidolysis reaction promoted by AcOH. Both these transformations co-generated acetone which converted glycerol into the corresponding acetals, while acidolysis sourced also acetic anhydride that acted as an acetylation reactant. However, tuning of conditions, mostly by changing the reactant molar ratio and optimizing the reaction time, was successful to steer the set of all reactions towards the synthesis of either a 1?:?1 mixture of acetal acetates (97% of which was solketal acetate) and triacetin, or acetal acetates in up to 91% yield, at complete conversion of glycerol. To the best of our knowledge, a one-pot protocol with such a degree of control on the functionalization of glycerol via transesterification and acetalization reactions has not been previously reported. The procedure was also easily reproduced on a gram scale, thereby proving its efficiency for preparative purposes. Finally, the design of experiments with isotopically labelled reagents, particularly d4-acetic acid and d6-acetone, helped to estimate the contribution of different reaction partners (iPAc/AcOH/acetone) to the formation of final products. This journal is
- Calmanti, Roberto,Perosa, Alvise,Rigo, Davide,Selva, Maurizio
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p. 5487 - 5496
(2020/09/23)
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- Method for synthesizing acetone ketal glycerinum acetate from glycerinum
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The invention discloses a method for synthesizing acetone ketal glycerinum acetate from glycerinum. The method comprises the following steps: firstly, putting acetone and a biodiesel byproduct, namelyglycerinum, into a condensation kettle, performing a condensation reaction in the presence of a catalyst A, and performing extraction and distillation after the reaction so as to obtain acetone ketalglycerinum; putting the acetone ketal glycerinum into a reaction/azeotropic distillation device, performing an ester exchange reaction with acetate in the presence of a catalyst B, and performing aftertreatment, so as to obtain a target product, namely the acetone ketal glycerinum acetate. Through condensation and ester exchange reactions, the biodiesel byproduct, namely the glycerinum, is converted into the acetone ketal glycerinum acetate which can be used as a fuel additive, separation is simple, the yield is high, the preparation process is simple, the catalyst is small in equipment corrosion, environment pollution caused by glycerinum wastes can be avoided, the environment can be protected, meanwhile, additional values of products can be increased, and development of the biodiesel industry can be facilitated.
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Paragraph 0018
(2019/12/25)
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Amorphous SiO2-SO3H [1] with a small surface area and 1.32-mmol H+/g was used for the one-step preparation of solketal from glycerol and acetone; a 20%-w/w catalyst mixture (10% [1] and 10% (Bu4N)(BF4) was found to be very efficient for the synthesis of disolketal ether and of oxygenated biofuels fatty acids solketal esters (FASEs), by direct esterification of the caprylic, lauric, stearic, oleic and linoleic acids with solketal in a 4:1 acid:solketal ratio in refluxing toluene. Solketal acetate was also produced in quantitative yields.
- Barbosa, Sandro L.,Lima, Pamela C.,dos Santos, Wallans T.P.,Klein, Stanlei I.,Clososki, Giuliano C.,Caires, Franco J.
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- Pheromone synthesis. Part 255: Synthesis and GC-MS analysis of pheromonal triacylglycerols of male Drosophila fruit flies
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Pheromonal triacylglycerols and their analogs, 1A, 1B, 2A, 2B, 3A, 3B, and 3C, of male Drosophila fruit flies were synthesized and analyzed by GC-MS. Their GC retention times were found to be a reliable measure to analyze and identify these triacylglycerols with acetyl, oleoyl and tigloyl groups, although the stereo- and regioisomers of 1 (1A and 1B), 2 (2A and 2B), and 3 (3A, 3B, and 3C) could not be distinguished from each other by MS alone.
- Mori, Kenji
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p. 5752 - 5762
(2015/03/30)
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- Green Acetylation of Solketal and Glycerol Formal by Heterogeneous Acid Catalysts to Form a Biodiesel Fuel Additive
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A glut of glycerol has formed from the increased production of biodiesel, with the potential to integrate the supply chain by using glycerol additives to improve biodiesel properties. Acetylated acetals show interesting cold flow and viscosity effects. Herein, a solventless heterogeneously catalyzed process for the acetylation of both solketal and glycerol formal to new products is demonstrated. The process is optimized by studying the effect of acetylating reagent (acetic acid and acetic anhydride), reagent molar ratios, and a variety of commercial solid acid catalysts (Amberlyst-15, zeolite Beta, K-10 Montmorillonite, and niobium phosphate) on the conversion and selectivities. High conversions (72–95 %) and selectivities (86–99 %) to the desired products results from using acetic anhydride as the acetylation reagent and a 1:1 molar ratio with all catalysts. Overall, there is a complex interplay between the solid catalyst, reagent ratio, and acetylating agent on the conversion, selectivities, and byproducts formed. The variations are discussed and explained in terms of reactivity, thermodynamics, and reaction mechanisms. An alternative and efficient approach to the formation of 100 % triacetin involves the ring-opening, acid-catalyzed acetylation from solketal or glycerol formal with excesses of acetic anhydride.
- Dodson, Jennifer R.,Leite, Thays d C. M.,S. Pontes, Nathália,Peres Pinto, Bianca,Mota, Claudio J. A.
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p. 2728 - 2734
(2016/12/23)
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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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- Selective esterifications of primary alcohols in a water-containing solvent
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Oxyma and an oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate (5b), displayed a remarkable effect on selective esterifications of primary alcohols. A wide range of carboxylic acids could be esterified with primary alcohols by using EDCI, NaHCO3, and Oxyma or Oxyma derivative 5b in 5% H2O-CH3CN. Oxyma derivative 5b is particularly useful, since it could be removed after the reaction via a simple basic or an acidic aqueous workup procedure.
- Wang, Yong,Aleiwi, Bilal A.,Wang, Qinghui,Kurosu, Michio
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supporting information
p. 4910 - 4913,4
(2012/12/12)
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- Selective esterifications of primary alcohols in a water-containing solvent
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Oxyma and an oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate (5b), displayed a remarkable effect on selective esterifications of primary alcohols. A wide range of carboxylic acids could be esterified with primary alcohols by using EDCI, NaHCO3, and Oxyma or Oxyma derivative 5b in 5% H2O-CH3CN. Oxyma derivative 5b is particularly useful, since it could be removed after the reaction via a simple basic or an acidic aqueous workup procedure.
- Wang, Yong,Aleiwi, Bilal A.,Wang, Qinghui,Kurosu, Michio
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supporting information
p. 4910 - 4913
(2013/01/15)
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- New approach to the synthesis of 1,3-dioxolanes
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Application of ethanol to the synthesis of 1,3-dioxolanes by the condensation of carbonyl compounds with vicinal diols results in a high yield of the reaction product and considerably reduces the duration of the process. It is assumed that the effect of the ethanol is caused by the adduct formation with carbonyl compounds (hemiacetals) which behave as active intermediates of the condensation. A cyclic ketal of acetone with glycerol obtained with the help of ethanol was used as a basis component in the synthesis of a series of ketals substituting diol or carbonyl components by transketalyzation mechanism proceeding without water liberation.
- Vol'Eva,Belostotskaya,Malkova,Komissarova,Kurkovskaya,Usachev,Makarov
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experimental part
p. 638 - 641
(2012/10/18)
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- Molecular iodine catalyzed selective acetylation of alcohols with vinyl acetate
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Molecular iodine is found to catalyze the acetylation of alcohols efficiently with vinyl acetate. The reaction is mild and selective with good to high yields. Molecular iodine displays significant functional group tolerance, being compatible with methoxy, double bonds, spiroketals, ketals and phenolic hydroxyl functions.
- Bosco, J.W. John,Agrahari, Aditya,Saikia, Anil K.
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p. 4065 - 4068
(2007/10/03)
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- A mild and efficient acetylation of alcohols, phenols and amines with acetic anhydride using La(NO3)3·6H2O as a catalyst under solvent-free conditions
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A wide variety of alcohols, phenols and amines are efficiently and selectively converted into the corresponding acetates by treatment with acetic anhydride in the presence of catalytic amounts of La(NO3)3·6H2O under solvent-free conditions at room temperature. The method is compatible with acid sensitive hydroxyl protecting groups such as TBDMS, THP, OBz, OBn, Boc and some isopropylidenes and offers excellent yields of the mono acetates of 1,3-, 1,4- and 1,5-diols.
- Reddy, T. Srikanth,Narasimhulu,Suryakiran,Mahesh, K. Chinni,Ashalatha,Venkateswarlu
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p. 6825 - 6829
(2007/10/03)
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- Fluorous distannoxane-catalyzed acetylation of alcohols in heterogeneous single fluorous solvent system
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Acetylation of alcohols with an equivalent amount of acetic anhydride is feasible in the presence of fluorous distannoxane catalyst in heterogeneous single fluorous system. The fluorous layer containing catalyst can be recycled and reused at least 10 times.
- Peng, Zhihong,Orita, Akihiro,An, Delie,Otera, Junzo
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p. 3187 - 3189
(2007/10/03)
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- Acetonyltriphenylphosphonium bromide (ATPB): A versatile reagent for the acylation of alcohols, phenols, thiols and amines and for 1,1-diacylation of aldehydes under solvent-free conditions
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A wide variety of alcohols, phenols, amines and thiols may easily be converted into the corresponding acetate derivatives by treatment with acetic anhydride (1.5-2.0 equivalents) in the presence of acetonyltriphenylphosphonium bromide (ATPB; 5 mol %) in good yields at room temperature. With the same precatalyst, both aliphatic and aromatic aldehydes can also be transformed into the corresponding gemdiacetates under reflux conditions.
- Khan, Abu T.,Choudhury, Lokman H.,Ghosh, Subrata
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p. 2782 - 2787
(2007/10/03)
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- Enhanced enantioselectivity of Bacillus coagulans in the hydrolysis of 1,2-O-isopropylidene glycerol esters by thermal knock-out of undesired enzymes
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The enantioselective hydrolysis of different (RS)-1,2-O-isopropylidene glycerol esters has been achieved with whole cells of Bacillus coagulans NCIMB 9365 furnishing the (S)-alcohol as the major enantiomer. The reaction is catalysed by a thermostable cell-bound carboxylesterase and improvement of the enantioselectivity has been achieved by heat treatment of the whole cells, which causes the knock-outs a non-enantioselective competing enzyme. Thermally-treated cells hydrolysed (RS)-1,2-O-isopropylidene glycerol esters with high enantioselectivity, the highest enantiomeric ratio (80-100) being observed for the benzoate. The biocatalyst displayed good stability and could be re-used after filtration for 12 cycles before showing significant loss of activity; repeated biotransformation batches allowed the recovery of 9.55 g/L of enantiomerically pure (S)-isopropylideneglycerol benzoate starting from 24.0 g/L of the racemic mixture.
- Romano, Diego,Falcioni, Francesco,Mora, Diego,Molinari, Francesco,Buthe, Andreas,Ansorge-Schumacher, Marion
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p. 841 - 845
(2007/10/03)
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- NITRIC OXIDE RELEASING PRODRUGS OF DIARYL-2-(5H)-FURANONES AS CYCLOOXYGENASE-2 INHIBITORS
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The invention encompasses novel compounds of Formula I, which are nitric oxide-releasing prodrugs of diaryl-2-(5H)-furanones useful in the treatment of cyclooxygenase-2 mediated diseases. Formula (I). The invention also encompasses certain pharmaceutical compositions and methods for treating cyclooxygenase-2 mediated diseases comprising the use of compounds of Formula 1. The above compounds may be used as a combination therapy with low-dose aspirin to treat chronic cyclooxygenase-2 mediated diseases or conditions while also reducing the risk of thrombotic cardiovascular events.
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Page/Page column 24-25
(2008/06/13)
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- Enantioselective hydrolysis of (RS)-isopropylideneglycerol acetate with Kluyveromyces marxianus
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The hydrolysis of (RS)-isopropylideneglycerol acetate with whole cells of the yeast Kluyveromyces marxianus is reported. The biotransformation furnished (R)-isopropylideneglycerol as major enantiomer with good enantioselectivity (E=28) under optimised conditions. The reaction can be performed in an ultrafiltration-membrane reactor allowing for the obtainment of 19.2g/L of enantiomerically pure (R)-isopropylideneglycerol acetate starting from 60g/L of racemic mixture.
- Molinari, Francesco,Cavenago, Kristin Solange,Romano, Andrea,Romano, Diego,Gandolfi, Raffaella
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p. 1945 - 1947
(2007/10/03)
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- Zn(ClO4)2·6H2O as a Powerful Catalyst for a Practical Acylation of Alcohols with Acid Anhydrides
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A new protocol for the acylation of alcohols with anhydrides in the presence of Zn(ClO4)2·6H2O as the catalyst is reported. The activity of Zn(ClO4)2· 6H2O has been proven to be superior to that exerted by dry Mg(ClO4)2 and by metal triflates. Its efficiency allows reactions between poorly reactive substrates, such as sterically hindered tertiary alcohols and aromatic anhydrides, All of the reactions were carried out at a 1:1.05 alcohol/anhydride ratio. These conditions are extremely convenient from a practical and economic point of view, since they avoid wasting reagents and allow a simple workup procedure. The catalytic action of Zn(ClO4)2·6H2O is so specific for the activation of the anhydrides, that acid-sensitive functionalities and the stereochemical configuration of the starting materials remain unaltered in the esterification process. In all cases, the acylated products are quantitatively obtained in pure form. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Bartoli, Giuseppe,Bosco, Marcella,Dalpozzo, Renato,Marcantoni, Enrico,Massaccesi, Massimo,Sambri, Letizia
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p. 4611 - 4617
(2007/10/03)
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- Highly enantioselective kinetic resolution of primary alcohols of the type Ph-X-CH(CH3)-CH2OH by Pseudomonas cepacia lipase: Effect of acyl chain length and solvent
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Although lipase from Pseudomonas cepacia (PCL) shows high enantioselectivity towards many secondary alcohols, it usually exhibits only low to moderate enantioselectivity towards primary alcohols. To increase this enantioselectivity, we optimised the reaction conditions for the PCL-catalysed hydrolysis of esters of three chiral primary alcohols: 2-methyl-3-phenyl-1- propanol 1, 2-phenoxy-1-propanol 2 and solketal 3. The enantioselectivity towards 1-acetate increased from E=16 to 38 upon changing the solvent from ethyl ether/phosphate buffer to 30% n-propanol in phosphate buffer and increased again to E ≥190 upon changing the substrate from 1-acetate to 1-heptanoate. The same changes increased the enantioselectivity towards alcohol 2 from E=17 to 70, but did not significantly increase the enantioselectivity towards alcohol 3. The best solvent was similar to the solvent used to crystallise the open form of PCL and likely stabilises the open form of PCL. This stabilisation may increase the enantioselectivity by removing kinetic contributions from a non-enantioselective lid-opening step. We determined the kinetic contribution of the lid-opening step by measuring the interfacial activation of PCL. The activation energy for the PCL-catalysed hydrolysis of ethyl acetate was at least 2.6 kcal/mol lower in the presence of a water-organic solvent interface.
- Mezzetti, Alessandra,Keith, Curtis,Kazlauskas, Romas J.
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p. 3917 - 3924
(2007/10/03)
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- Process for preparation of 1,3-dioxolane-4-methanol compounds
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PCT No. PCT/JP97/03165 Sec. 371 Date Feb. 8, 1999 Sec. 102(e) Date Feb. 8, 1999 PCT Filed Sep. 9, 1997 PCT Pub. No. WO98/11087 PCT Pub. Date Mar. 19, 1998A process for preparing easily and economically a 1,3-dioxolane-4-methanol compound in a racemic form or an optically active form with high purity and in high yield. The process comprises reacting an alkali metal or alkaline earth metal salt of an alcohol or a carboxylic acid with a halogenomethyl-1,3-dioxolane which is prepared by acetalizing a halogeno-1,2-propanediol of a formula (1) wherein X is a halogen atom, in an acid catalyst to conduct esterification or etherification, and then hydrolyzing the ester group and hydrogenolyzing the ether group to prepare a 1,3-dioxolane-4-methanol compound of a formula (5) wherein R1 and R2 are hydrogen atom, alkyl having 1 to 4 carbon atoms or phenyl, and R1 and R2 may form a cycloalkyl ring having 3 to 6 carbon atoms with the adjacent carbon atoms.
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- Highly Selective Acylation of Alcohols Using Enol Esters Catalyzed by Iminophosphoranes
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The iminophosphorane bases PhCH2N=P(MeNCH2CH2)3N and PhCH2N=P(NMe2)3 catalyze the acylation of primary alcohols with enol esters in excellent yields and in high selectivity. It was found that acid labile groups such as acetal and epoxide survive under the reaction conditions. Groups such as TBS and disulfide, which undergo cleavage in the presence of Ac2O and the Lewis acid Sc(OTf)3, are also unaffected. Diene, conjugated acetylene, oxazoline, nitro, and benzodioxane groups are also compatible with our catalyst/reagent system. Because secondary alcohols do not react under our conditions, our methodology is attractive for the selective acylation of primary alcohols. Polymer-supported iminophosphorane catalysts are also shown to be useful in these reactions, thus opening the possibility of wider applications.
- Ilankumaran, Palanichamy,Verkade, John G.
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p. 9063 - 9066
(2007/10/03)
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- A Selectivity Study of Activated Ketal Reduction with Borane Dimethyl Sulfide
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A chemo- and regioselectivity study of the reagent combination BH3*SMe2/TMSOTf for ketal reduction has been undertaken.It has revealed that simple 1,3-dioxanes reduce cleanly at low temperature in CH2Cl2 while simple 1,3-dioxolanes may give complete ring cleavage and dimerization products.A study of reduction of 4-substituted 1,3-dioxolanes has revealed a solvent-directed regioselectivity which in THF favors the secondary protected derivative.A mechanism is postulated to account for the selectivities based on recent thinking on acetal substitution reactions.
- Bartels, Birgit,Hunter, Roger
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p. 6756 - 6765
(2007/10/02)
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- 3-pyrrolidinylthio-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid compounds
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3-Pyrrolidinylthio-1-azabicyclo [320] hept-2-ene-2-carboxylic acid anti-microbiotic compounds are prepared.
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- Iodoaryl analogues of dioctanoylglycerol and 1-oleoyl-2-acetylglycerol as probes for protein kinase C
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Analogues of dioctanoylglycerol (diC8) and 1-oleoyl-2-acetylglycerol (OAG) containing an iodoaryl group have been synthesized and shown to compete with [3H]phorbol dibutyrate ([3H]PDBu) for binding to protein kinase C in a crude rat brain preparation. Phorbol diesters have been shown to bind specifically to protein kinase C and the PDBu receptor has been copurified with protein kinase C activity. All three diacylglycerol analogues were comparable to OAG in binding affinity. In an assay of protein kinase C activation, the diC8 analogue was more active than the OAG analogues, thus demonstrating greater structural specificity under the conditions of this assay.
- Strawn,Martell,Simpson,Leach,Counsell
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p. 2104 - 2110
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF PROTECTED α-HYDROXYACETALDEHYDES
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Starting from 2,3-O-isopropylideneglycerol (1), a general procedure for the preparation of protected α-hydroxyacetaldehydes has been developed.
- Shiao, Min-Jen,Yang, Chia-Yu,Lee, Shi-Hung,Wu, Teh-Chun
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p. 359 - 366
(2007/10/02)
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- 3-ACYL-2-OXAZOLONE-ZIRCONIUM COMPLEXES AS EXCELLENT REAGENTS FOR HIGHLY REGIOSELECTIVE ACYLATION OF POLYALCOHOLS
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In combination with 3-acyl-2-oxazolones, zirconium complexes such as zirconium acetylacetonate and zirconocene chloride hydride-Mg serve well as effective catalysts for regioselective acylation of polyalcohols including 1,2-diols to permit higly preferential protection of primary hydroxyl groups.
- Kunieda, Takehisa,Mori, Takashi,Higuchi, Tsunehiko,Hirobe, Masaaki
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p. 1977 - 1980
(2007/10/02)
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