- Chemoselective Oxidation of Secondary Hydroxy Groups by the Molybdenum Hexacarbonyl/Cetylpyridinium Chloride/t-Butyl Hydroperoxide System
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The system molybdenum hexacarbonyl/cetylpyridinium chloride/t-butyl hydroperoxide in benzene is used for the chemoselective oxidation of secondary hydroxy compounds to the corresponding carbonyl derivatives.
- Yamawaki, Kazumasa,Yoshida, Tsutomu,Suda, Takashi,Ishii, Yasutaka,Ogawa, Masaya
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Read Online
- Enzymatic syntheses of 13C-enriched geranylgeranyl diphosphate and casbene from 13C-labeled isopentenyl diphosphate
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Geranylgeranyl diphosphate and casbene were synthesized in high yields from [4-13c]-3-methyl-3- butenyl diphosphate, using coupled enzyme reactions.
- Huang, Qiulong,Huang, Kexue,Scott
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Read Online
- HIGHLY SELECTIVE OXIDATION OF SECONDARY HYDROXYL FUNCTIONS USING THE VO(acac)2-t-BuOOH SYSTEM
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The VO(acac)2-t-BuOOH system shows high oxidation reactivity for secondary alkohols to give ketones.
- Kaneda, Kiyotomi,Kawanishi, Yasuyuki,Jitsukawa, Koichiro,Teranishi, Shiichiro
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Read Online
- Process for preparing 4-hydroxy-2-butanone
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The invention provides a process for preparing 4-hydroxy-2-butanone. Amino acid is used as a catalyst to catalyze the condensation reaction of formaldehyde and acetone at normal temperature, so as tosynthesize 4-hydroxy-2-butanone in one step. The yield of the prepared 4-hydroxy-2-butanone is high, the purity reaches 98%, the production cost is reduced, the corrosion effect caused by the use of astrong base catalyst is avoided, the catalyst and the solvent can be recycled for 10 times or more, and the whole synthesis process is economical and environment-friendly.
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Paragraph 0024-0044
(2020/12/31)
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- Hydroxycarbonyl compound (by machine translation)
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After the separated and purified efficiently and easily by hydroxycarbonyl compound [a] of production method. [Solution] a carbonyl compound having a hydrogen atom at α-position with paraformaldehyde, acidic or basic catalyst is added to the environment is not reacting with the method. Figure 1 [drawing] (by machine translation)
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Paragraph 0070
(2020/01/31)
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- Preparation method of hydroxyl ketone compound
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The invention discloses a preparation method of a hydroxyl ketone compound. The method comprises a step of converting dihydric alcohol into a hydroxyl ketone compound in the presence of a copper-basedcatalyst, namely a conversion step, and the reaction conditions of the conversion step are as follows: the reaction temperature is 200-400 DEG C, the reaction pressure is 0.01-0.5 MPa, and the liquidhour space velocity is 0.1-10 h. The method has a high raw material conversion rate and high selectivity of the hydroxyl ketone compound with terminal hydroxyl, and is easy to implement industrially.
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Paragraph 0024-0036; 0039-0048; 0055-0059
(2020/07/12)
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- Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound i Type Oxidants
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The reductive activation of molecular oxygen catalyzed by iron-based enzymes toward its use as an oxygen donor is paradigmatic for oxygen transfer reactions in nature. Mechanistic studies on these enzymes and related biomimetic coordination compounds designed to form reactive intermediates, almost invariably using various "shunt" pathways, have shown that high-valent Fe(V)=O and the formally isoelectronic Fe(IV) =O porphyrin cation radical intermediates are often thought to be the active species in alkane and arene hydroxylation and alkene epoxidation reactions. Although this four decade long research effort has yielded a massive amount of spectroscopic data, reactivity studies, and a detailed, but still incomplete, mechanistic understanding, the actual reductive activation of molecular oxygen coupled with efficient catalytic transformations has rarely been experimentally studied. Recently, we found that a completely inorganic iron-tungsten oxide capsule with a keplerate structure, noted as {Fe30W72}, is an effective electrocatalyst for the cathodic activation of molecular oxygen in water leading to the oxidation of light alkanes and alkenes. The present report deals with extensive reactivity studies of these {Fe30W72} electrocatalytic reactions showing (1) arene hydroxylation including kinetic isotope effects and migration of the ipso substituent to the adjacent carbon atom ("NIH shift"); (2) a high kinetic isotope effect for alkyl C - H bond activation; (3) dealkylation of alkylamines and alkylsulfides; (4) desaturation reactions; (5) retention of stereochemistry in cis-alkene epoxidation; and (6) unusual regioselectivity in the oxidation of cyclic and acyclic ketones, alcohols, and carboxylic acids where reactivity is not correlated to the bond disassociation energy; the regioselectivity obtained is attributable to polar effects and/or entropic contributions. Collectively these results also support the conclusion that the active intermediate species formed in the catalytic cycle is consistent with a compound I type oxidant. The activity of {Fe30W72} in cathodic aerobic oxidation reactions shows it to be an inorganic functional analogue of iron-based monooxygenases.
- Bugnola, Marco,Shen, Kaiji,Haviv, Eynat,Neumann, Ronny
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p. 4227 - 4237
(2020/05/05)
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- High purity 1,3-butanediol and its preparation method
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The present invention relates to a high purity 1,3-butanediol and a preparation method thereof. The preparation method of the present invention comprises: a step (a) of mixing distilled water, a buffer solution and paraformaldehyde to obtain a mixture, and heating the mixture to prepare formaldehyde; a step (b) of mixing formaldehyde of the step (a) (s100) with acetone, and making the formaldehyde of the step (a) react with the acetone to prepare a mixed solution as an intermediate; a step (c) of reducing the intermediate of the step (b) (s200) to prepare 1,3-butanediol; and a step (d) of deodorizing/purifying 1,3-butanediol of the step (c) (s300). According to the present invention, the high purity 1,3-butanediol prepared by the preparation method not only can be used as raw material for various resins such as polyester resins, alkyd resins, urethane resins, urethane coatings and the like as industrial uses, but also can be diversely used in other fabric softeners, pharmaceuticals, dyestuffs and others. Further, the high purity 1,3-butanediol not only can be used as a moisturizer for a cosmetic composition, perfume and hair since slight intoxication is not generated although the high purity 1,3-butanediol is stored for a long period, but also can be used in a preparation for spice of food products or the like.(AA) Start(BB) End(S10) Step of preparing high purity formaldehyde(S200) Step of preparing an intermediate(S300) Step of reducing the intermediate(S400) Step of performing deodorizing and purifying operationsCOPYRIGHT KIPO 2019
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Paragraph 0172; 0181; 0182
(2019/05/25)
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- Production method of 4-hydroxy-2-butanone
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Belonging to the field of fine chemicals, the invention discloses a production method of 4-hydroxy-2-butanone, and solves the problem of low yield of existing synthetic methods. The method provided bythe invention includes the steps of: adding 1, 3-butanediol, a catalyst, an assistant, water and a water-carrying agent into a reaction kettle, and performing heating to 55-60DEGC; adding hydrogen peroxide dropwise into the mixed solution, and conducting reduced pressure distillation of water; stopping adding hydrogen peroxide, and further performing stirring for 1-1.5h to distill the water-carrying agent out; controlling the temperature of the system not higher than 60DEGC, and conducting reduced pressure rectification to obtain the final product 4-hydroxy-2-butanone. By adding the assistant, 1, 3-butanediol can better participate in the reaction, and the conversion rate can be improved. The chemical reaction carried out in the invention is carried out under a negative pressure condition, and the temperature is controlled not higher than 60DEG C, thus avoiding the generation of methyl vinyl ketone; and in a negative pressure system, the reaction can be fully carried out under a low temperature condition, the product is easier to distill, and impurities are not easily produced.
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Paragraph 0018-0027
(2019/10/01)
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- Aerobic Oxidation of Secondary Alcohols with Nitric Acid and Iron(III) Chloride as Catalysts in Fluorinated Alcohol
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Fluorinated alcohols as solvents strongly influence and direct chemical reaction through donation of strong hydrogen bonds while being weak acceptors. We used 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the activating solvent for a nitric acid and FeCl3-catalyzed aerobic oxidation of secondary alcohols to ketones. Reaction proceeded selectively with excellent yields with no reaction on the primary alcohol group. Oxidation of benzyl alcohols proceeds selectively to aldehydes with only HNO3 as the catalyst, while reaction on tertiary alcohols proceeds through dehydration and dimerization. A mechanistic study showed in situ formation of NOCl that converts alcohol into alkyl nitrite, which in the presence of Fe3+ ions and fluorinated alcohol decomposes into ketone. The study indicates that iron(III) acts also as the single-electron transfer catalyst in regeneration of NOCl reactive species.
- Mo?ina, ?tefan,Iskra, Jernej
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p. 14579 - 14586
(2019/11/14)
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- Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction
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The invention provides a method for synthesizing diene compounds based on an aldehyde-ketone condensation reaction. The method comprises the following steps: firstly, under the action of a condensation catalyst, performing a condensation reaction on ketone compounds and aldehyde compounds to obtain condensation products; then, under the action of a reduction catalyst, performing a reduction reaction on the condensation products obtained in the previous step to obtain reduction products; under the action of a catalyst, performing a dehydration reaction on the reduction products obtained in theprevious step to obtain the diene compounds. According to the method, ketone, aldehyde as well as homologues of ketone and aldehyde which are cheap and easy to obtain can be used as raw materials forsynthesizing the diene compounds such as butadiene, piperylene as well as homologues of butadiene and piperylene, experimental conditions are mild, the operation is simple, and a large-scale synthesisprospect is achieved.
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Paragraph 0156-0160; 0205-0207
(2019/05/08)
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- BORYL ETHERS, CARBONATES, AND CYCLIC ACETALS AS OXIDATIVELY-TRIGGERED DRUG DELIVERY VEHICLES
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A compound, or a pharmaceutically acceptable salt thereof, having a structure of Formula (I), wherein L is a cleavable linker group; X is a cargo moiety-containing group; and R1 and R2 are each independently hydrogen, alkyl, or substituted alkyl; or R1 and R2 together form a boronic ester ring or a substituted boronic ester group.
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Page/Page column 30
(2018/03/28)
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- Synthesis method of 4-hydroxy-2-butanone
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The invention provides a synthesis method of 4-hydroxy-2-butanone. The method comprises the following steps of (1), adding certain amounts of 1,3-butanediol, catalyst, water and water entrainer into a reaction vessel, uniformly agitating an obtained first mixture, so as to form a mixed solution, and increasing a temperature to 60 to 75 DEG C; (2), continuously agitating the mixed solution, dropwise adding hydrogen peroxide of which the mass concentration is 25 to 35 percent into the mixed solution, and carrying out distillation hydration while dropwise adding the hydrogen peroxide; (3), when the content of the 1,3-butanediol in the reaction vessel is detected to be lower than 5 percent of an initial content, stopping dropwise adding the hydrogen peroxide, continuously agitating an obtained second mixture for 0.5h to 1.5h; (4), controlling a temperature in the reaction vessel, and distilling off the water entrainer; (5), decreasing the temperature in the reaction vessel to 60 to 65 DEG C, and distilling an obtained third mixture to obtain a target-product 4-hydroxy-2-butanone. By using the synthesis method of the 4-hydroxy-2-butanone, which is provided by the invention, a by-product only comprises the water; the purity of a product is high; further, the post treatment of a reaction is easy; the pollution does not exist nearly; further, the production cost is lower.
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Paragraph 0032; 0033; 0034; 0035; 0036; 0037; 0038; 0039
(2017/08/28)
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- A process for synthesizing of raspberry ketone
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The invention discloses a synthesis process of raspberry ketone. The synthesis process comprises the following steps: (1) synthesizing butanone alcohol in the presence of a catalyst namely NaOH by adopting a theta-ring stainless steel packing fixed bed reactor and taking formaldehyde and acetone as raw materials; (2) synthesizing raspberry ketone in the presence of a catalyst namely ion exchange resin D218 by taking butanone alcohol and phenol as raw materials and adopting a fluidized bed reactor. According to the synthesis process disclosed by the invention, butanone alcohol is synthesized in the presence of the catalyst namely NaOH by taking acetone and formaldehyde as raw materials, so that the synthesis process has the advantages of low cost, short reaction time, simplicity and convenience in operation, less side reactions, high yield and the like; and raspberry ketone is synthesized in the presence of the catalyst namely the strongly acid cation exchange resin D218, the equipment corrosivity during the process is small, the after treatment is simple, and the reuse rate of the catalysts is high. The synthesis process is a novel efficient and environment-friendly production method.
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Paragraph 0032-0035
(2017/01/09)
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- Catalytic dehydrogenation of 1,2- and 1,3-diols
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Described are studies of the dehydrogenation of 1,2- and 1,3-diols in homogenous solutions catalyzed by {[2,5-diphenyl-3,4-ditoluyl-(η5-C4CO)]2H}Ru2(CO)4(μ-H) (otherwise known as the Casey/Shvo catalyst). Both in the presence and absence of a dihydrogen acceptor, these reactions led to the analogous α-hydroxyketone as the only organic product. Isotopic labeling studies indicate that this product arises from reversible dehydrogenation/hydrogenation reactions, resulting in formation of the thermodynamically favored α-hydroxyketone. When this catalytic dehydrogenation was carried out in the presence of the rhodium decarbonylation catalyst Rh(dppp)2Cl (dppp = 1,3-bis(diphenylphosphino)propane), modest amounts of carbon monoxide result, suggesting that the dehydrogenation does generate at least some aldehydes that are intercepted by this catalyst. However, the efficiency of the latter reaction is poor.
- Weber, Madeline A.,Ford, Peter C.
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supporting information
p. 81 - 87
(2016/04/05)
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- Alcohol, Aldehyde, and Ketone Liberation and Intracellular Cargo Release through Peroxide-Mediated α-Boryl Ether Fragmentation
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α-Boryl ethers, carbonates, and acetals, readily prepared from the corresponding alcohols that are accessed through ketone diboration, react rapidly with hydrogen peroxide to release alcohols, aldehydes, and ketones through the collapse of hemiacetal intermediates. Experiments with α-boryl acetals containing a latent fluorophore clearly demonstrate that cargo can be released inside cells in the presence of exogenous or endogenous hydrogen peroxide. These experiments show that this protocol can be used for drug activation in an oxidative environment without generating toxic byproducts.
- Hanna, Ramsey D.,Naro, Yuta,Deiters, Alexander,Floreancig, Paul E.
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supporting information
p. 13353 - 13360
(2016/10/22)
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- A structure/catalytic activity study of gold(i)-NHC complexes, as well as their recyclability and reusability, in the hydration of alkynes in aqueous medium
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We conducted a structure/catalytic activity study of water-soluble gold(i) complexes-supporting sulfonated NHC ligands-in the hydration of alkynes in pure water or water nsp;:nsp;methanol (1nsp;:nsp;1), as well as their recyclability. Comparative studies were carried out with the addition of different silver salts. Our results indicate that the bulkier complex is the most effective and that the addition of methanol as co-solvent not only shortens reaction times but also stabilizes the less bulky complexes.
- Fernández, Gabriela A.,Chopa, Alicia B.,Silbestri, Gustavo F.
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p. 1921 - 1929
(2016/04/05)
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- Reversible catalytic dehydrogenation of alcohols for energy storage
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Reversibility of a dehydrogenation/hydrogenation catalytic reaction has been an elusive target for homogeneous catalysis. In this report, reversible acceptorless dehydrogenation of secondary alcohols and diols on iron pincer complexes and reversible oxidative dehydrogenation of primary alcohols/reduction of aldehydes with separate transfer of protons and electrons on iridium complexes are shown. This reactivity suggests a strategy for the development of reversible fuel cell electrocatalysts for partial oxidation (dehydrogenation) of hydroxyl-containing fuels.
- Bonitatibus, Peter J.,Chakrabortyb, Sumit,Doherty, Mark D.,Siclovan, Oltea,Jones, William D.,Soloveichik, Grigorii L.
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p. 1687 - 1692
(2015/03/05)
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- Electrochemistry for the generation of renewable chemicals: Electrochemical conversion of levulinic acid
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The oxidative and reductive electrochemical conversion of levulinic acid to its primary products valeric acid, γ-valerolactone, 2,7-octanedione, 4-hydroxy-2-butanone and 3-buten-2-one is studied in detail. The reactions were performed in aqueous solutions and at ambient temperature, following the principles of green chemistry. The obtained primary reaction products were studied with respect to the oxidative and reductive electrochemical formation of secondary products, such as n-octane, 1-butanol and 1,3-butanediol. It is shown that the choice of electrolyte composition, educt concentration and the nature of the electrode material has a strong influence on the selectivity of product formation. For instance it is demonstrated that in alkaline solutions γ-valerolactone can be gained from levulinic acid at iron electrodes with similar Coulombic efficiency (~20%) but higher selectivity (S = 70%) than on lead (S = 50%). Furthermore, for the first time the electrochemical two-step reaction of levulinic acid to 1-butanol via 4-hydroxy-2-butanone is reported. For some of the reaction pathways the main product is water insoluble, which allows a direct separation of the product and the potential electrolyte reuse in a semi-continuous process. Especially the use of the electrocatalytic hydrogenation may provide a path for the storage of electricity into liquid organic fuels as shown by a basic energetic assessment of all electrochemical conversions.
- Dos Santos, Tatiane R.,Nilges, Peter,Sauter, Waldemar,Harnisch, Falk,Schr?der, Uwe
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p. 26634 - 26643
(2015/03/30)
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- Regioselective hydration of terminal alkynes catalyzed by a neutral gold(I) complex [(IPr)AuCl] and one-pot synthesis of optically active secondary alcohols from terminal alkynes by the combination of [(IPr)AuCl] and Cp?RhCl[(R, R)-TsDPEN]
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A neutral gold(I) complex [(IPr)AuCl] (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene) was found to be a highly effective catalyst for the hydration of terminal alkynes, including aromatic alkynes and aliphatic alkynes. The desired methyl ketones were obtained in high yields with complete regioselectivities. Furthermore, a series of optically active secondary alcohols could be obtained in high yield with good to excellent enatioselectivities via one-pot sequential hydration/asymmetric transfer hydrogenation (ATH) from terminal alkynes by the combination of of [(IPr)AuCl] and Cp?RhCl[(R,R)-TsDPEN] (Cp? = pentamethylcyclopentadienyl, TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine). Notably, this research exhibited the potential of the direct use of neutral gold(I) complexes instead of cationic ones as catalysts for the activation of multiple bonds for organic synthesis.
- Li, Feng,Wang, Nana,Lu, Lei,Zhu, Guangjun
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p. 3538 - 3546
(2015/04/14)
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- Ligand- and Acid-Free Gold(I) Chloride Catalyzed Hydration of Terminal Alkynes
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Our work shows that simple alkynes can be hydrated by the AuCl/MeOH catalyst system to afford the corresponding methyl ketones in moderate to high yields without any additive, ligand, or acid promoter. This methodology is simpler, milder, and operationally easier than those reported before. The reaction media significantly affects the reaction, and methanol is found to be the best solvent. Both aliphatic and aromatic terminal alkynes were able to undergo hydration, affording moderate to excellent yields under the reaction conditions used in the present work, and excellent functional-group tolerance was also observed. A plausible mechanism for the hydration reaction was proposed.
- Das, Atanu Kumar,Park, Sangseung,Muthaiah, Senthilkumar,Hong, Soon Hyeok
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p. 2517 - 2520
(2015/11/16)
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- Water-Soluble Gold-N-Heterocyclic Carbene Complexes for the Catalytic Homogeneous Acid- and Silver-Free Hydration of Hydrophilic Alkynes
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Water-soluble gold(III/I) N-heterocylic carbene complexes behave as efficient catalysts for the hydration of terminal alkynes in neat water. The transformation proceeds in the absence of Bronsted acids or halide scavengers and is suitable for sensitive substrates. Kinetic profiles and DFT studies provide a clear picture of intermediates present during catalysis.
- Ibrahim, Houssein,Defrmont, Pierre,Braunstein, Pierre,Thry, Vincent,Nauton, Lionel,Cisnetti, Federico,Gautier, Arnaud
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p. 3893 - 3900
(2016/01/25)
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- Synthesis of natural maleimides farinomaleins C-E and evaluation of their antifungal activity
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A practical and convenient synthesis of naturally occurring farinomaleins C-E was achieved starting from readily available ethyl 3-methyl-2-oxobutyrate and triethyl phosphonoacetate. The key steps of the sequence included a Horner-Wadsworth-Emmons condensation to obtain the precursor farinomalein A and coupling with suitable alcohols to install the chain. The synthesis of farinomalein D has been achieved starting from (R)-isopropylideneglycerol on the basis of which the S configuration was assigned to the natural compound. The antifungal activity of the synthesized compounds was evaluated against Cladosporium cladosporioides.
- Lahore, Santosh,Aiwale, Sachin T.,Sardi, Paola,Dallavalle, Sabrina
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p. 4196 - 4198
(2014/07/22)
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- Synthesis of natural maleimides farinomaleins C-E and evaluation of their antifungal activity
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A practical and convenient synthesis of naturally occurring farinomaleins C-E was achieved starting from readily available ethyl 3-methyl-2-oxobutyrate and triethyl phosphonoacetate. The key steps of the sequence included a Horner-Wadsworth-Emmons condensation to obtain the precursor farinomalein A and coupling with suitable alcohols to install the chain. The synthesis of farinomalein D has been achieved starting from (R)-isopropylideneglycerol on the basis of which the S configuration was assigned to the natural compound. The antifungal activity of the synthesized compounds was evaluated against Cladosporium cladosporioides.
- Lahore, Santosh,Aiwale, Sachin T.,Sardi, Paola,Dallavalle, Sabrina
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p. 4196 - 4198
(2015/02/05)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF DOLUTEGRAVIR
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The present invention provides (R)-3-Amino-1-butanol (D)-tartarate (lIb); process for its preparation and its conversion to Dolutegravir. The present invention also provides an improved process for the preparation of Dolutegravir (I) or pharmaceutically acceptable salts wherein compound (XVI) is reacted with an optically active acid addition salt of (R)-3-amino-1-butanol (lla).
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Page/Page column 20; 23
(2014/09/03)
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- Well-defined iron catalysts for the acceptorless reversible dehydrogenation-hydrogenation of alcohols and ketones
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Acceptorless dehydrogenation of alcohols, an important organic transformation, was accomplished with well-defined and inexpensive iron-based catalysts supported by a cooperating PNP pincer ligand. Benzylic and aliphatic secondary alcohols were dehydrogenated to the corresponding ketones in good isolated yields upon release of dihydrogen. Primary alcohols were dehydrogenated to esters and lactones, respectively. Mixed primary/secondary diols were oxidized at the secondary alcohol moiety with good chemoselectivity. The mechanism of the reaction was investigated using both experiment and DFT calculations, and the crucial role of metal-ligand cooperativity in the reaction was elucidated. The iron complexes are also excellent catalysts for the hydrogenation of challenging ketone substrates at ambient temperature under mild H2 pressure, the reverse of secondary alcohol dehydrogenation.
- Chakraborty, Sumit,Lagaditis, Paraskevi O.,F?rster, Moritz,Bielinski, Elizabeth A.,Hazari, Nilay,Holthausen, Max C.,Jones, William D.,Schneider, Sven
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p. 3994 - 4003
(2015/01/16)
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- Heterogeneously catalyzed oxidation of butanediols in base free aqueous media
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The oxidation of four butanediols under base-free conditions has been investigated using a set of Au, Pd and Pt catalysts prepared using sol-immobilization. The supported nanoparticles are found to be active with bimetallic alloys having much higher activity when compared with the monometallic counterparts. In general the AuPt catalysts are the most active and in all cases the corresponding C4 oxidation products were observed with high selectivity; sequential reaction of these products leads to the formation of acetic acid as an undesired by-product.
- Ryabenkova, Yulia,Miedziak, Peter J.,Knight, David W.,Taylor, Stuart H.,Hutchings, Graham J.
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p. 6055 - 6058
(2014/12/10)
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- Heterogeneously catalyzed oxidation of butanediols in base free aqueous media
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The oxidation of four butanediols under base-free conditions has been investigated using a set of Au, Pd and Pt catalysts prepared using sol-immobilization. The supported nanoparticles are found to be active with bimetallic alloys having much higher activity when compared with the monometallic counterparts. In general the AuPt catalysts are the most active and in all cases the corresponding C4 oxidation products were observed with high selectivity; sequential reaction of these products leads to the formation of acetic acid as an undesired by-product.
- Ryabenkova, Yulia,Miedziak, Peter J.,Knight, David W.,Taylor, Stuart H.,Hutchings, Graham J.
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p. 6055 - 6058
(2015/03/30)
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- Upgrading of diols by gas-phase dehydrogenation and dehydration reactions on bifunctional Cu-based oxides
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Biomass-derived short-chain polyols can be transformed into valuable oxygenates used as building blocks. The gas phase conversion of a model molecule of 1,3-diols (1,3-butanediol), was studied on bifunctional Cu-Mg, Cu-Al and Cu-Mg-Al mixed oxide catalysts that exhibit surface Cu0 particles and acid-base properties. A series of ZCuMgAl catalysts (Z = 0.3-61.2 wt.% Cu, Mg/Al = 1.5 molar ratio) was prepared by coprecipitation and thoroughly characterized by several techniques such as BET surface area, TPR-N2O chemisorption, XRD and TPD of CO2. The ZCuMgAl catalysts promote the upgrading of diols by a series of dehydrogenation and/or dehydration reactions proceeding at reaction rates that depend on the copper content (Z). The overall activity increases linearly with the amount of surface Cu0 species thereby confirming the participation of metallic sites in the rate-limiting steps. Besides, surface Cu0 sites favor the reaction pathway toward 1,3-butanediol dehydrogenation. Thus, the dehydrogenation/dehydration selectivity ratio increases with Z as a result of the enhanced amount of exposed Cu0 particles. ZCuMgAl catalysts with Z 4 ketones and break the intermediates forming C1-C 3 oxygenates; catalysts with Z > 8 wt.% have higher activity and yield valuable multifunctional C4 oxygenates such as hydroxyketones and, to a lesser extent, unsaturated alcohols and ketones. A strongly basic Cu-Mg catalyst promotes the C-C bond cleavage reaction giving short carbon chain oxygenates at low rates; an acidic Cu-Al catalyst converts the diol into C 4 saturated ketones and olefins. the Partner Organisations 2014.
- Torresi,Diez,Luggren,Di Cosimo
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p. 3203 - 3213
(2014/08/18)
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- Production of Higher Alcohols
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A reactive distillation method comprises introducing a feed stream to a reactive distillation column, contacting the feed stream with one or more catalysts in the reactive distillation column during a distillation, and removing one or more higher alcohols during the distillation from the reactive distillation column as a bottoms stream. The feed stream comprises one or more alpha hydrogen alcohols, and the feed stream reacts in the presence of the one or more catalysts to produce a reaction product comprising the one or more higher alcohols.
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Paragraph 0194-0195
(2014/09/03)
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- Base-free, acceptorless, and chemoselective alcohol dehydrogenation catalyzed by an amide-derived NNN -ruthenium(II) hydride complex
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The bmpi (1,3-bis(6′-methyl-2′-pyridylimino)isoindoline) pincer Ru(II) hydride complex catalyzes base-free, acceptorless, and chemoselective dehydrogenation of alcohols with liberation of dihydrogen under moderate (120 C) conditions. Primary alcohols and diols are converted to ester and lactone products with high conversion efficiencies. The catalyst system is remarkably selective for the oxidation of secondary alcohols in the presence of primary alcohols.
- Tseng, Kuei-Nin T.,Kampf, Jeff W.,Szymczak, Nathaniel K.
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supporting information
p. 2046 - 2049
(2013/05/22)
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- Conversion of diols by dehydrogenation and dehydration reactions on silica-supported copper catalysts
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The gas-phase conversion of a 1,3-polyol (1,3-butanediol) containing primary and secondary OH functions was studied on a series of copper-silica catalysts, ZCuSiO2 (Z = 1-25 wt.% Cu), and thoroughly characterized by several techniques such as BET surface area, TPR, XRD, N2O chemisorption, and UV-vis-DRS. The physicochemical properties of the ZCuSiO 2 catalysts depended on whether the metal loading was above or below the copper monolayer surface coverage (Z = 13.5 wt.% Cu). Copper species presenting different degrees of interaction with the silica support were detected. At low Z values Cu0 dispersion was high (D ≈ 40%) due to a predominant contribution of nano-sized Cu species (3 nm) which are difficult to reduce, but for Z > 13.5 wt.%, D abruptly dropped to 3-8% because of formation of larger tridimensional Cu clustered species (30 nm) that reduced at lower temperatures because of a decreased copper-silica interaction. On ZCuSiO2 catalysts, dehydrogenation of the 1,3-butanediol secondary OH function prevailed over that of the primary one and therefore valuable ketones were the main reaction products. Consecutively to dehydrogenation, dehydration and hydrogenation reactions also took place. Products of the tandem reaction were the β-hydroxy ketone (4-hydroxy-2-butanone), the α,β- unsaturated ketone (methyl vinyl ketone) and the saturated ketone (methyl ethyl ketone). A direct 1,3-butanediol dehydration pathway toward methyl ethyl ketone was also found. Reaction pathways were strongly dependent on the Cu loading and therefore on the kind of Cu species (isolated or clustered). When compared at similar conversion levels, selectivity to the dehydrogenation product 4-hydroxy-2-butanone increased with Z suggesting that on large Cu0 particles 4-hydroxy-2-butanone was released to the gas phase before being converted in consecutive steps. On the contrary, on highly dispersed Cu 0 crystals of low Cu loading catalysts, 1,3-butanediol was readily dehydrated giving the saturated ketone. Kinetically relevant reaction steps of 1,3-butanediol conversion by dehydrogenation and dehydration were promoted on Cu0 sites. Dehydration of the intermediate 4-hydroxy-2-butanone also occurred on Cu0 sites. Turnover rates were constant on Cu0 nano particles and slightly higher on clustered species.
- Torresi,Díez,Luggren,Di Cosimo
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p. 119 - 129
(2013/07/19)
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- Gas-phase rate coefficients for the OH + n -, i -, s -, and t-butanol reactions measured between 220 and 380 K: Non-arrhenius behavior and site-specific reactivity
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Butanol (C4H9OH) is a potential biofuel alternative in fossil fuel gasoline and diesel formulations. The usage of butanol would necessarily lead to direct emissions into the atmosphere; thus, an understanding of its atmospheric processing and environmental impact is desired. Reaction with the OH radical is expected to be the predominant atmospheric removal process for the four aliphatic isomers of butanol. In this work, rate coefficients, k, for the gas-phase reaction of the n-, i-, s-, and t-butanol isomers with the OH radical were measured under pseudo-first-order conditions in OH using pulsed laser photolysis to produce OH radicals and laser induced fluorescence to monitor its temporal profile. Rate coefficients were measured over the temperature range 221-381 K at total pressures between 50 and 200 Torr (He). The reactions exhibited non-Arrhenius behavior over this temperature range and no dependence on total pressure with k(296 K) values of (9.68 ± 0.75), (9.72 ± 0.72), (8.88 ± 0.69), and (1.04 ± 0.08) (in units of 10-12 cm3 molecule-1 s-1) for n-, i-, s-, and t-butanol, respectively. The quoted uncertainties are at the 2σ level and include estimated systematic errors. The observed non-Arrhenius behavior is interpreted here to result from a competition between the available H-atom abstraction reactive sites, which have different activation energies and pre-exponential factors. The present results are compared with results from previous kinetic studies, structure-activity relationships (SARs), and theoretical calculations and the discrepancies are discussed. Results from this work were combined with available high temperature (1200-1800 K) rate coefficient data and room temperature reaction end-product yields, where available, to derive a self-consistent site-specific set of reaction rate coefficients of the form ATn exp(-E/RT) for use in atmospheric and combustion chemistry modeling.
- McGillen, Max R.,Baasandorj, Munkhbayar,Burkholder, James B.
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p. 4636 - 4656
(2013/07/25)
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- Sulfonated water-soluble N-heterocyclic carbene silver(I) complexes: Behavior in aqueous medium and as NHC-transfer agents to platinum(II)
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This report describes the synthesis of water-soluble silver(I) and platinum(II) complexes bearing sulfonated mono- or dianionic N-heterocyclic carbene ligands. Thus, treatment of the corresponding zwitterionic imidazolium derivative with silver(I) oxide in water afforded the light-sensitive bis(carbene) complexes Ag[Ag(NHC)2] (2Ag+), which were transformed into the stable salts Na[Ag(NHC)2] (2) by addition of sodium chloride. In contrast, the same reaction in dmso afforded mono(carbenes) of general formula Na[AgCl(NHC)] (3). The solvent-dependence of the reaction product can be rationalized on the basis of the equilibrium [AgCl 2]- - AgCl + Cl-. The precipitation of silver chloride is more favored in protic solvents than in aprotic solvents such as dmso, thus explaining the formation of bis(carbenes) in water. The formation of silver chloride may also promote the hydrolysis of silver NHC complexes under some conditions. The water-soluble platinum(II) complexes Na[PtCl 2(dmso)(NHC)] were synthesized by using either mono(carbene) silver complexes 3 as carbene-transfer agents or by direct metalation of the imidazolium salt with cis-[PtCl2(dmso)2] in the presence of NaHCO3 as base. The (NHC)Pt(II) complexes were tested as catalysts for the hydration of alkynes in the aqueous phase and found to be active in neat water without the need for acidic cocatalysts.
- Baquero, Edwin A.,Silbestri, Gustavo F.,Gomez-Sal, Pilar,Flores, Juan C.,De Jesus, Ernesto
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p. 2814 - 2826
(2013/06/26)
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- METHOD FOR MANUFACTURING KETONE
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A method for manufacturing a ketone, includes oxidizing an internal olefin or a cyclic olefin having a functional group containing a hetero atom and one carbon-carbon double bond or more at a position other than terminals of a molecule thereof in an amide-based solvent in the presence of water, a palladium catalyst, and molecular oxygen, without oxidizing the functional group, thereby bonding an oxo group to at least one of the carbon atoms constituting the carbon-carbon double bond. The amide-based solvent is represented by formula (1): wherein R1 represents an alkyl group having 1 to 4 carbon atoms; R2 and R3 each independently represent an alkyl group having 1 to 4 carbon atoms or an aryl group; and when R1 and R2 are alkyl groups, R1 and R2 may be bonded to each other to form a ring structure.
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Page/Page column 9
(2012/08/08)
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- Platinum(II) diphosphinamine complexes for the efficient hydration of alkynes in micellar media
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Highly active monomeric bis-cationic platinum(II) catalysts bearing small bite angle diphosphinamine [N,N-bis(diarylphosphino)amine] 'PNP' ligands efficiently catalyze Markovnikov hydration of terminal and internal alkynes to the corresponding ketones in water. Catalyst solubilization in water is achieved via ion pairing with anionic micelles formed by surfactant addition. The micelles ensure dissolution of apolar alkynes and promote the intimate contact between reagents and catalyst, while in organic-water media in the absence of surfactants the reaction is sluggish. Hydration products can be isolated by means of extraction with an apolar solvent and the catalyst, that remains confined in the aqueous phase, can be recycled up to four times without loss of catalytic activity. Copyright
- Trentin, Francesco,Chapman, Andrew M.,Scarso, Alessandro,Sgarbossa, Paolo,Michelin, Rino A.,Strukul, Giorgio,Wass, Duncan F.
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scheme or table
p. 1095 - 1104
(2012/05/20)
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- Chemoselective aerobic diol oxidation by palladium(II)-pyridine catalysis
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Neutral and cationic palladium complexes that bear pyridine ligands [i.e., pyridine (Py), 4-ethylpyridine (4-EtPy) and 2,4,6-trimethylpyridine (2,4,6-Me3Py)] have been isolated and characterized in solution by 1H and 13C{1H} NMR spectroscopy, cyclic voltammetry (CV) and in the solid state by elemental analysis and single-crystal structure analysis. All palladium compounds have been scrutinized as a precursor to catalyze the aerobic oxidation of diols either in the presence or in the absence of an external base (i.e., K2CO3). As a result, the chemoselective production of the corresponding hydroxy ketones has been achieved. The bis-cationic palladium complex of the formula [Pd(4-EtPy)4](OTs)2 (OTs = p-toluenesulfonate) [5b(OTs)2] emerged as the most promising precursor; it outperformed the neutral precursor that consisted of trans-[Pd(OAc)2(4-EtPy) 2] (OAc = acetate) and 4-EtPy [3b/2(4-EtPy)] (2 mol-equiv.). An operando high-pressure (HPNMR) spectroscopic study with the precursor 5b(OTs)2 combined with the results obtained from catalytic reactions has provided insight into the catalytic mechanism that is operative in 5b(OTs)2-catalyzed aerobic diol oxidation reactions. Neutral and cationic palladium(II) complexes with pyridine ligands were synthesized and employed as catalyst precursors for the aerobic K2CO 3-assisted oxidation of unprotected diols to chemoselectivelygive hydroxy ketones. Within the series of catalyst precursors studied, the bis-cationic compound [Pd(4-EtPy)4](OTs)2 (Py = pyridine, OTs = p-toluenesulfonate) emerged as the most promising.
- Bettucci, Lorenzo,Bianchini, Claudio,Filippi, Jonathan,Lavacchi, Alessandro,Oberhauser, Werner
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experimental part
p. 1797 - 1805
(2011/06/25)
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- Chemoselective aerobic oxidation of unprotected diols catalyzed by Pd-(NHC) (NHC = N-heterocyclic carbene) complexes
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Neutral Pd(X)(η3-allyl) (X = Cl, OAc (acetate)) complexes bearing mono-coordinating NHC ligands have been synthesized, characterized and employed to catalyze the aerobic oxidation of unprotected 1,2- and 1,3-diols selectively to hydroxy ketones. A comparison of the catalytic performance of these precursors with a reference system has shown that the precursor with the ligands N,N′-bis(adamantyl)imidazol-2-ylidene and chloride is the most efficient for the chemoselective oxidation of 1,2-diols is concerned. High-pressure 1H NMR (HPNMR) experiments in combination with catalytic batch reactions have provided valuable information on the activation of the precursor as well as on the stability of the catalysts.
- Bettucci, Lorenzo,Bianchini, Claudio,Oberhauser, Werner,Hsiao, Tsun-Hung,Lee, Hon Man
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experimental part
p. 63 - 72
(2010/07/08)
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- Selective catalytic oxidation of glycerol to dihydroxyacetone
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High selectivity and high yield characterize the oxidation of glycerol into dihydroxyacetone using catalyst 1, with benzoquinone or air as the oxidant. The mechanism proposed involves reversible palladium-alkoxide formation with the turnover-limiting reoxidation of the palladium complex. Copyright
- Painter, Ron M.,Pearson, David M.,Waymouth, Robert M.
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supporting information; experimental part
p. 9456 - 9459
(2011/03/19)
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- Selective deprotection of silyl ethers with sodium periodate
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Highly selective deprotection of silyl ethers by NaIO4 in THF-H2O (4:1) is reported. The mild neutral conditions enable efficient applications to complex, polyfunctional, and sensitive substrates. Georg Thieme Verlag Stuttgart.
- Li, Jun,Menche, Dirk
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experimental part
p. 1904 - 1908
(2009/12/31)
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- Aldol condensation reaction and catalyst therefore
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The invention relates to a novel processes for cross aldol reactions using strongly basic, anionic, macroreticular polymeric resin with quaternary ammonium groups of the type -CH2N+(CH3)3 as heterogeneous catalysts. This catalyst is recyclable and the process can be repeated several times.
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Page/Page column 6
(2009/01/20)
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- TiCl4/tert-butyl hydroperoxide: Chemioselective oxidation of secondary alcohols and suppression of sharpless epoxidation
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Replacing Ti(Oi-Pr)4 with TiCl4 under the normal Sharpless epoxiation conditions resulted in a shut down of the epoxidation reaction. Instead, a chemioselective oxidation of secondary alcohols in the presence of primary alcohols occurred. Georg Thieme Verlag Stuttgart.
- Shei, Chun-Tin,Chien, Hao-Lun,Sung, Kuangsen
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experimental part
p. 1021 - 1026
(2009/04/04)
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- [α-PW12O40]3- immobilized on ionic liquid-modified polymer as a heterogeneous catalyst for alcohol oxidation with hydrogen peroxide
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Ionic liquid-modified polystyrene resin beads were demonstrated to be an appropriate support for polyoxometalate. In this heterogeneous catalytic system, alcohols can be efficiently oxidized to corresponding carbonyl groups with H2O2 in CH3CN. The catalyst can be easily recovered by filtration and recycled without apparent loss of catalytic performance. Copyright Taylor & Francis Group, LLC.
- Lang, Xianjun,Li, Zhen,Xia, Chungu
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p. 1610 - 1616
(2008/09/21)
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- Heteropoly acid-based supported ionic liquid-phase catalyst for the selective oxidation of alcohols
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A supported ionic liquid strategy has been applied for the immobilization of a heteropolyacid, molybdovanadophosphoric acid, onto ionic liquid-modified mesoporous silica SBA-15. The immobilized catalyst demonstrated high activity in the aerobic oxidation of primary and secondary alcohols to aldehydes and ketones, respectively. No overoxidation of the primary alcohols to carboxylic acids was observed. Secondary alcohols were chemoselectively oxidized to ketones in the presence of primary alcohol, hetero atom, and allyl groups. This catalyst could be recycled five times without obvious loss of activity.
- Bordoloi, Ankur,Sahoo, Suman,Lefebvre,Halligudi
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experimental part
p. 232 - 239
(2009/03/11)
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- Selective photooxidation of diols with silica bound W10 O324 -
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The decatungstate anion W10 O324 - has been heterogenized on silica previously functionalized with different ammonium cations covalently bound to the surface of the solid support. These materials are investigated as photocatalysts for the oxygen-assisted oxidation of 1,3-butanediol and 1,4-pentanediol. Product distribution and adsorption experiments indicate that the polarity of the environment surrounding the photoactive anion plays a crucial role in controlling the adsorption of diols on the surface and, consequently, their reaction with the photoexcited decatungstate. Proper reaction conditions are found for obtaining more than 90% of 4-hydroxy-2-butanone from 1,3-butanediol and for stopping the oxidation of 1,4-pentanediol to 4-hydroxypentanal with good yield. The employed photocatalysts present a very good stability in repeated experiments.
- Maldotti,Molinari,Bigi
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p. 312 - 317
(2008/09/16)
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- New amino endoperoxides belonging to the antimalarial G-factor series
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In the search for new antimalarial endoperoxides we developed a direct route for the preparation of new amino compounds belonging to the G-factor series. During the synthesis, a significant difference in reactivity between two series of diastereoisomers was observed. The final amino endoperoxides were obtained with 58 to 70 % yields, depending on the starting amine, in the "anti" series, but with the "syn" diastereoisomers an unexpected rearrangement occurred during the deprotection step. This was attributed to a transient hexacoordinate fluorosilicon complex allowing the formation of a 1,2-dioxetane. Its decomposition gave aldehyde 12 and 4-hydroxybutan-2-one; these compounds were also identified when acidic conditions were used in the deprotection step. The anti amino compounds obtained were tested, but in vitro activities were found to be lower than initially expected, and fitted poorly with the previous biological hypothesis. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Givelet, Cecile,Bernat, Virginie,Danel, Mathieu,Andre-Barres, Christiane,Vial, Henri
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p. 3095 - 3101
(2008/02/08)
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- DMSO/N2H4·H2O/I2/H 2O/CH3CN: A new system for selective oxidation of alcohols in hydrated media
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A new alternative system for the oxidation of secondary alcohols to ketones with DMSO/N2H4·H2O/I2/H 2O/CH3CN in hydrated media has been developed. The system also selectively oxidizes the secondary alcoholic groups to the corresponding ketones in the presence of primary alcoholic groups present within the same molecule in moderate to very good yields at reflux temperature.
- Gogoi, Pranjal,Sarmah, Gautam Kumar,Konwar, Dilip
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p. 5153 - 5154
(2007/10/03)
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- Rate constants for the gas-phase reactions of OH radicals with a series of hydroxyaldehydes at 296 ± 2 K
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Using a relative rate method with in situ generation of the hydroxyaldehydes, rate constants for the reactions of the OH radical with 2-hydroxybutanal [CH3CH2CH(OH)CHO], 3-hydroxybutanal [CH3CH(OH)CH2CHO], 2-hydroxypropanal [CH 3CH(OH)CHO], 2-hydroxy-2-methylpropanal [(CH3) 2C(OH)CHO], and 3-hydroxy-propanal [HOCH2CH 2CHO] have been measured at atmospheric pressure and 296 ± 2 K. The hydroxy-aldehydes were generated in situ from the OH radical-initiated reactions of precursor compounds (1,2- and 1,3-butanediol, 2-methyl-2,4-pentanediol, 2-methyl-3-buten-2-ol, and cis-3-hexen-1-ol) and the rate constants for the reaction of OH radicals with the hydroxyaldehydes were determined relative to those for reaction of OH radicals with the precursor compound. The rate constants obtained (in units of 10-11 cm 3 molecule-1 s-1) were CH3CH 2CH(OH)CHO, 2.37 ± 0.23; CH3CH(OH)CH 2CHO, 2.95 ± 0.24; CH3CH(OH)CHO, 1.70 ± 0.20; (CH3)2C(OH)CHO, 1.40 ± 0.25; and HOCH 2CH2CHO, 1.99 ± 0.29.
- Baker, Jillian,Arey, Janet,Atkinson, Roger
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p. 7032 - 7037
(2007/10/03)
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- Unusual reversal of regioselectivity in antibody-mediated aldol additions with unsymmetrical methyl ketones
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A catalytic regio- and enantioselective aldol reaction of various unsymmetrical methyl ketones with para-nitrobenzaldehyde has been developed using aldolase antibodies as the catalysts. It has been found that the sense and level of regioselectivity for the reactions catalysed by antibody 38C2 and 33F12 are highly dependent on the structure of both the donor and the acceptor but in contrast, antibodies 84G3 and 93F3 catalyse the exclusive formation of the linear regioisomer independent of the structure of the reactants examined. The level of enantiocontrol is very high for most reactions. Both linear aldol enantiomers could be accessed through aldol or retro-aldol reactions using the same antibody. Theoretical studies on regioisomeric α- and β-heteroatom substituted enamines derived from unsymmetrical ketones suggest that most of the linear aldol products formed in the presence of antibodies 84G3 and 93F3 must be formed from intermediate enamines which are not the thermodynamically most favourable.
- Maggiotti,Bahmanyar,Reiter,Resmini,Houk,Gouverneur
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p. 619 - 632
(2007/10/03)
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- Practical application of recombinant whole-cell biocatalysts for the manufacturing of pharmaceutical intermediates such as chiral alcohols
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We have developed efficient biocatalytic processes for the preparation of chiral alcohols, such as (R)-1,3-butanediol, ethyl (S)-4-chloro-3-hyroxybutanoate, ethyl (R)-4-chloro-3-hyroxybutanoate, (S)-5-chloro-2-pentanol, (R)-5-chloro-2-pentanol, and (S)-cyclopropylethanol by stereospecific enzymatic oxidoreduction on a practical level. These chiral alcohols are very important synthons for the synthesis of various pharmaceutical intermediates that lead to antibiotics and inhibitors of HMG-CoA reductase. Here, we present practical applications on biocatalysis using novel recombinant whole-cell biocatalysts that catalyzed enantioselective oxidation and asymmetric reduction with a coenzyme regeneration system.
- Matsuyama, Akinobu,Yamamoto, Hiroaki,Kobayashi, Yoshinori
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p. 558 - 561
(2013/09/06)
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- Kinetics and products of the reactions of selected diols with the OH radical
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Using a relative rate method, rate constants been measured at 296 ± 2 K for the gas-phase reactions of OH radicals with 1,2-butanediol, 2,3-butanediol, 1,3-butanediol, and 2-methyl-2,4-pentanediol, with rate constants (in units of 10-12 cm3 molecule-1 s-1) of 27.0 ± 5.6, 23.6 ± 6.3, 33.2 ± 6.8, and 27.7 ± 6.1, respectively, where the error limits include the estimated overall uncertainty of ±20% in the rate constant for the reference compound. Gas chromatographic analyses showed the formation of 1-hydroxy-2-butanone from 1,2-butanediol, 3-hydroxy-2-butanone from 2,3-butanediol, 1-hydroxy-3-butanone from 1,3-butanediol, and 4-hydroxy-4-methyl-2-pentanone from 2-methyl-2,4-pentanediol, with formation yields of 0.66 ± 0.11, 0.89 ± 0.09, 0.50 ± 0.09, and 0.47 ± 0.09, respectively, where the indicated errors are the estimated overall uncertainties. Pathways for the formation of these products are presented, together with a comparison of the measured and estimated rate constants and product yields.
- Bethel, Heidi L.,Atkinson, Roger,Arey, Janet
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p. 310 - 316
(2007/10/03)
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- Oxidation of alcohols by dimethyldioxirane
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The kinetics of oxidation of a series of monoalomic alcohols (methanol, 2-propanol, 2-butanol, 2-methyl-1-propanol, 2-chloroethanol, 1,3-dichloro-2-propanol, benzyl alcohol), hydroxyacetic acid, and 1,3-butandiol (ROH) by dimethyldioxirane (1) was studied. The reaction kinetics obeys the second order equation w = k[ROH][1]. The rate constants were measured in the range of 7 - 50 C, and the activation parameters were found. To describe the reaction rate constants as a function of the ROH structure, the two-parametric Taft equation was used, which takes into account both the polar and resonance substituent effects. Alcohol oxidation produces the corresponding carbonyl compounds, viz., ketones from secondary alcohols and aldehydes from primary alcohols, in yields of at least 80%. The results were explained by the competition of the molecular (oxenoid) and radical mechanisms. The introduction of electron-withdrawing substituents into the alcohol molecule increases the contribution of the radical channel of the reaction.
- Grabovskii,Suvorkina,Kabal'nova,Khursan,Shereshovets
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p. 1332 - 1337
(2007/10/03)
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- Efficient oxidation of alcohols to carbonyl compounds with molecular oxygen catalyzed by N-hydroxyphthalimide combined with a Co species
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Highly efficient catalytic oxidation of alcohols with molecular oxygen by N-hydroxyphthalimide (NHPI) combined with a Co species was developed. The oxidation of 2-octanol in the presence of catalytic amounts of NHPI and Co(OAc)2 under atmospheric dioxygen in AcOEt at 70 °C gave 2-octanone in 93% yield. The oxidation was significantly enhanced by adding a small amount of benzoic acid to proceed smoothly even at room temperature. Primary alcohols were oxidized by NHPI in the absence of any metal catalyst to form the corresponding carboxylic acids in good yields. In the oxidation of terminal vic-diols such as 1,2-butanediol, carbon-carbon bond cleavage was induced to give one carbon less carboxylic acids such as propionic acid, while internal vic-diols were selectively oxidized to 1,2-diketones.
- Iwahama, Takahiro,Yoshino, Yasushi,Keitoku, Takashi,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 6502 - 6507
(2007/10/03)
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