- Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
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The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
- Lambert, Tristan H.,Steiniger, Keri A.
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supporting information
p. 8013 - 8017
(2021/10/25)
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- Method and system for producing 1, 3-propylene glycol by multi-step method
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The invention discloses a method and a system for producing 1, 3-propylene glycol by a multi-step method. The method comprises the following steps: carrying out dehydration reaction on 1, 3-dichloropropanol and a dehydration catalyst to prepare 1, 3-dichloropropene; carrying out a first hydrolysis reaction on a first mixed reaction system containing the 1, 3-dichloropropene, a first hydrolysis agent and a first solvent to prepare 3-chloro-2-propene-1-alcohol; carrying out hydrogenation reaction on the 3-chloro-2-propene-1-alcohol and a hydrogenation catalyst to prepare 3-chloropropanol; and carrying out a second hydrolysis reaction on a second mixed reaction system containing the 3-chloropropanol, a second hydrolysis agent and a second solvent to prepare the 1, 3-propylene glycol. According to the method, 1, 3-dichloropropanol is used as a raw material, the important chemical raw material 1, 3-propylene glycol is prepared through a dehydration, hydrolysis, hydrogenation and hydrolysisfour-step method, and the method has the advantages of mild reaction conditions, low cost, environmental protection, economy and the like.
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Paragraph 0101; 0106-0107; 0110; 0115-0116; 0119; 0124-0125
(2021/01/28)
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- An Ultrasensitive Fluorescence Assay for the Detection of Halides and Enzymatic Dehalogenation
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Halide assays are important for the study of enzymatic dehalogenation, a topic of great industrial and scientific importance. Here we describe the development of a very sensitive halide assay that can detect less than a picomole of bromide ions, making it very useful for quantifying enzymatic dehalogenation products. Halides are oxidised under mild conditions using the vanadium-dependent chloroperoxidase from Curvularia inaequalis, forming hypohalous acids that are detected using aminophenyl fluorescein. The assay is up to three orders of magnitude more sensitive than currently available alternatives, with detection limits of 20 nM for bromide and 1 μM for chloride and iodide. We demonstrate that the assay can be used to determine specific activities of dehalogenases and validate this by comparison to a well-established GC-MS method. This new assay will facilitate the identification and characterisation of novel dehalogenases and may also be of interest to those studying other halide-producing enzymes.
- Aslan-üzel, A?k?n S.,Beier, Andy,Ková?, David,Cziegler, Clemens,Padhi, Santosh K.,Schuiten, Eva D.,D?rr, Mark,B?ttcher, Dominique,Hollmann, Frank,Rudroff, Florian,Mihovilovic, Marko D.,Bury?ka, Tomá?,Damborsky, Ji?í,Prokop, Zbyněk,Badenhorst, Christoffel P. S.,Bornscheuer, Uwe T.
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p. 2032 - 2039
(2020/02/11)
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- Chemical synthesis method of 3-chloro-1-propanol
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The invention belongs to the technical field of chemical synthesis, and concretely relates to a chemical synthesis method of 3-chloro-1-propanol. 1,3-propylene glycol reacts with hydrochloric acid with benzenesulfonic acid as a catalyst to synthesize 3-chloro-1-propanol. The method comprises the following steps: 1,3-propylene glycol, a part of hydrochloric acid and benzenesulfonic acid are added into a reaction kettle and are reacted, the remaining hydrochloric acid is added into the reaction kettle, the obtained mixture is continuously reacted until the sampling analysis result shows that thesample is qualified, toluene is added, a heating reflux water-carrying reaction is carried out, the kettle is cooled to room temperature after the water-carrying reaction is completed, an oil phase in the kettle is neutralized to be neutral, the oil phase is pumped into a rectifying kettle, and is rectified until the sampling analysis result shows that the sample is qualified, and the finished product is separated out. The method which adopts the benzenesulfonic acid as the catalyst has the advantages of increase of the reaction efficiency, prevention of excessive chlorination, no generationof high-toxicity and high-pollution three wastes in the reaction, recyclability of byproducts, realization of the comprehensive yield of 95% or above, high conversion rate, high operability, low riskand low industrialization difficulty.
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Paragraph 0030-0043
(2020/01/25)
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- ADENOSINE A3 RECEPTOR MODULATING COMPOUNDS AND METHODS OF USE THEREOF
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Provided herein is a method of preventing, treating, or ameliorating one or more symptoms of an adenosine A3-mediated condition, disorder, or disease, with a compound of Formula I. Also provided herein is a method of preventing, treating, or ameliorating one or more symptoms of glaucoma or ocular hypertension. Further provided herein is a method of modulating the activity of an adenosine A3 receptor.
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- MANUFACTURE OF DICHLOROPROPANOL
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Manufacture of dichloropropanol Process for manufacturing dichloropropa nol wherein a glycerol-based product comprising at least one diol containi ng at least 3 carbon atoms other than 1,2- propanediol, is reacted with a chlorinati ng agent, and of products derived from dichloropropanol such as ep ichlorohydrin and epoxy resins. No figure.
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Page/Page column 18-19
(2009/03/07)
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- Magnetically separable Pd catalyst for highly selective epoxide hydrogenolysis under mild conditions
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A magnetically separable palladium catalyst was synthesized simply through a sol-gel process incorporating palladium nanoparticles and superparamagnetic iron oxide nanoparticles in aluminum oxyhydroxide matrix, which is highly active and selective for epoxide hydrogenolysis at room temperature under 1 atm H 2. The catalyst was recycled for 25 times without loss of the activity.
- Kwon, Min Serk,Park, In Soo,Jang, Jum Suk,Lee, Jae Sung,Park, Jaiwook
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p. 3417 - 3419
(2008/02/12)
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- Oxidation of monohydric and dihydric alcohols with CCl4 catalyzed by molybdenum compounds
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Mo(CO)6 catalyzed oxidation of alcohols and diols with tetrachloromethane. Primary oxidation products in reaction of alcohols with CCl4 are alkyl hypochlorites, and final products depending on the structure of initial alcohol are aldehydes (as acetals), ketones, chloroketones, and esters.
- Khusnutdinov,Shchadneva,Burangulova,Muslimov,Dzhemilev
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p. 1615 - 1621
(2007/10/03)
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- Sodium borohydride-solid LiClO4: An effective reagent for reducing aldehydes and ketones in aprotic solvent
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An efficient and simple method for the reduction of aldehydes, ketones and acid chlorides has been accomplished by using NaBH4-solid LiClO 4 in mild conditions at ambient temperature with complete chemoselectivity in reduction of α,β-unsaturated aldehydes and ketones. The reaction is fast with high yield and simple workup. Copyright Taylor & Francis, Inc.
- Halimjani, Azim Ziyaei,Saidi, Mohammad R.
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p. 2271 - 2276
(2007/10/03)
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- A bimetallic system for the catalytic hydroxylation of remote primary C- H bonds in functionalized organics using dioxygen
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In a mixture of trifluoroacetic acid and water, the combination of metallic palladium and copper chloride catalyzes the hydroxylation of remote primary C-H bonds of a variety of acids, alcohols, and aliphatic halides, in the presence of carbon monoxide and dioxygen. Experiments suggest that the principal role of metallic palladium is to generate hydrogen peroxide in situ and that the species responsible for the remote hydroxylation of the substrate by hydrogen peroxide is copper chloride. The unusual preference for the catalytic hydroxylation of primary C-H bonds was also found in an experiment involving competition between ethane and either cumene or p- isopropylbenzoic acid: even though the solution concentration of ethane was significantly lower than the competing substrate, the vast majority of the oxidation product (ethanol) was derived from ethane. In the reactions studied, acetic acid and formic acid were formed through C-C cleavage steps. An examination of the site of C-C cleavage in propionic acid indicated that both C-C bonds were being broken.
- Shen, Chengyu,Garcia-Zayas, Eduardo A.,Sen, Ayusman
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p. 4029 - 4031
(2007/10/03)
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- A simple and efficient method for selective deprotection of t- butyldimethylsilyl ethers by zinc tetrafluoroborate in water
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Selective deprotection of t-butyldimethylsilyl ethers has been achieved under mild conditions using an aqueous solution of zinc tetrafluoroborate.
- Ranu, Brindaban C.,Jana, Umasish,Majee, Adinath
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p. 1985 - 1988
(2007/10/03)
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- Regioselective reduction of epoxides and conjugated carbonyl compounds using zeolite supported zinc borohydride
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Zeolite supported zinc borohydride is a versatile catalyst for the regeoselective reduction of epoxides, conjugated ketones, and aldehydes to the corresponding alcohols in good yields.
- Sreekumar,Padmakumar,Rugmini
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p. 5151 - 5154
(2007/10/03)
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- Benzopyranones, a method for producing them and uses therefor
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Novel 2H-1-benzopyran-2-ones (coumarin derivatives) of the general formula (I) are provided: STR1 wherein R1, R2, R3, R4, X and Y are defined as in the specification, and the addition compounds thereof with physiologically compatible acids, intermediates and methods for the preparation thereof. The coumarin compounds possess a neuroprotective and anti-allergic action.
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- Selective reducing agents
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A process for selective reduction is provided wherein an organic compound containing a reducible group such as acid, acid chloride, ester, aldehyde, ketone, epoxide, amide, oxime, imine, nitrile, or the like, is reacted with a tertiary amine alane such that an alcohol or an amine is produced, substantially without reduction of another group in the molecule such as a halogen-containing functionality, nitro group, or double bond.
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- Regio- and Stereo-selective Reductive Cleavage of Epoxides with Zinc Borohydride Supported on Silica Gel
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Reductive cleavage of unsymmetrical alkyl-substituted epoxides to less substituted alcohols has been achieved in a simple procedure using zinc borohydride supported on silica gel.
- Ranu, Brindaban C.,Das, Asish R.
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p. 1334 - 1335
(2007/10/02)
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- Cleavage of saturated oxygen heterocycles by a dinuclear molybdenum complex containing sulfido and hydrosulfido ligands
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The cationic complex [(MeCpMo)2(S2CH2)(μ-S)(μ-SH)]SO 3CF3 (1) reacted with tetrahydrofuran to form a cationic derivative with a μ-4-hydroxybutanethiolate ligand, [(MeCpMo)2(S2CH
- Godziela,Tonker,Rakowski DuBois
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p. 2220 - 2224
(2008/10/08)
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- Equilibrium Constants for the Interconversion of Substituted 1-Phenylethyl Alcohols and Ethers. A Measurement of Intramolecular Electrostatic Interactions
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Equilibrium constants for the reactions of ring-substituted 1-phenylethyl alcohols with a series of aliphatic alcohols of pKa 12.4-16 to form the corresponding ethers, and for interconversion of the ethers, have been determined in 50:45:5 HOH/CF3CH2OH/ROH (v/v/v), μ = 0.5 (NaCIO4), at 25 deg C.Formation of ethers from the alcohols is favorable, with values of K = 3-74; replacement of water by methanol is favored by factors of 50-74.Equilibrium constants increase with increasing pKa of the alcohol with values of βeq = δlog K/δpKROH in the range 0.17-0.27.This is attributed to hydrogen bonding of the alcohol to the solvent and to an electrostatic interaction between substituents on the alcohol and the aryl group.The contribution from hydrogen bonding to the solvent is estimated to be β = 0.17; for 90percent HOH it is 0.25.An increase in βeq with electron-withdrawing substituents on the benzene ring and a complementary increase in ρeq with electron-donating substituents on ROH are described by an electrostatic interaction coefficient τ = δβeq/δ? = δρeq/δpKROH = 0.10 +/- 0.01.No change in τ for dipole-dipole interactions was observed with increasing water concentration in the range 50-90percent (v/v).The electrostatic interactions that are described by τ can cause changes in structure-reactivity parameters, such as ρ or β, in the absence of changes in transition-state structure.
- Rothenberg, Marc E.,Richard, John P.,Jencks, William P.
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p. 1340 - 1346
(2007/10/02)
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- Selective Reductions. 35. Reaction of Representative Organic Functional Groups with Lithium Borohydride in the Presence of B-Methoxy-9-borabicyclononane. A Simple, Convenient Procedure for the Catalyzed Selective Reduction of Esters
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The rate of reduction of esters by lithium borohydride is considerably enhanced by a number of Lewis acids of boron.The remarkable catalytic effect of B-MeO-9-BBN and (MeO)3B in enhancing the reactivity of lithium borohydride toward the reduction of other representative functional groups has been explored.Alkyl halides are not reduced.Epoxides are readily reduced in 0.25 h.Carboxylic acids are reduced rapidly up to 50percent, with further reaction being very slow.Acid salts are not reduced.Tertiary amides are slowly reduced in the presence of 100 mol percent of B-MeO-9-BBN, 40percent in 24 h.Nitriles, under the same conditions, are reduced completely in 5 h.Pyridine and nitrobenzene are not significantly affected by this system.Sulfides, sulfoxides, and sulfones are also inert.However, tosylates are reduced rapidly.These results indicate the utility of this catalytic effect for the ready reduction of esters by lithium borohydride, as well as the ability of this reducing system to tolerate many substituents in such reductions.
- Brown, Herbert C.,Narasimhan, S.
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p. 3891 - 3898
(2007/10/02)
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- Cyclodehydration and Chlorination of Simple Diols with Triphenylphosphine and tert-Butyl Hypochlorite
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The reagent triphenylphosphine-tert-butyl hypochlorite converts 1,4-diols into the corresponding tetrahydrofurans and 1,2-diols into a mixture of the regioisomeric chlorohydrins and the epoxides at -78 deg C followed by warming to ambient temperature (ca. 30 deg C).Symmetrical diols give largely chlorohydrins and dichlorides.
- Barry, Carey N.,Evans, Slayton A.
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p. 2825 - 2828
(2007/10/02)
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- New Powerful Catalysts for the Reduction of Esters by Lithium Borohydride
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The presence of 10 mmol percent of lithium 9-boratabicyclononane, LiH*9-BBN, or lithium triethylborohydride, LiEt3BH, strongly catalyzes the reduction of esters by lithium borohydride in ether at 25 deg C.The corresponding Lewis acid, B-methoxy-9-borabicyclononane, B-OMe-9-BBN, also permits the rapid and quantitative reduction of esters by LiBH4 and provides a practical method for the reduction of esters by LiBH4 and provides a practical method for the reduction of esters in the presence of reducible groups, such as chloro and nitro.
- Brown, Herbert C.,Narasimhan, S.
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p. 1604 - 1606
(2007/10/02)
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- Hydroboration. 57. Hydroboration with 9-Borabicyclononane of Alkenes Containing Representative Functional Groups
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The hydroboration of alkenes containing representative functional groups was examined with 9-borabicyclononane (9-BBN) in order to extend the hydroboration reaction for the preparation of functionally substituted organoboranes.Terminal alkenes containing a remote functional group are hydroborated with a remarkable regioselectivity (>=98percent terminal), producing the corresponding stable organoboranes. 9-BBN hydroborates the allylic derivatives so as to place boron essentially on the terminal carbon atom (>=97percent).The directive effect is further enhanced (>=99percent) in the case of β-methylallyl derivatives.The hydroboration of crotyl derivatives attaches boron predominantly at the 2-position, followed by an elimination-rehydroboration sequence.However, crotyl alcohol can be protected against elimination as the tert-butyl or tetrahydropyranyl ethers.The hydroboration-oxidation of ethyl crotonate involves a series of elimination, hydroboration, and condensation processes.In the vinyl, crotyl, and isobutenyl systems, the mesomeric effect of the substituent favors the placement of boron at the β-position, while the inductive effect favors the α-position, with the former effect predominating in most cases.Acyclic β-substituted organoboranes undergo rapid elimination.Nonpolar solvents and lower reaction temperatures decrease the rate of elimination.However, those derived from cyclic vinyl derivatives are relatively stable under neutral conditions, undergoing facile elimination in the presence of a base.
- Brown, Herbert C.,Chen, Jackson C.
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p. 3978 - 3988
(2007/10/02)
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- Polar Substituent Effects in the Solvolysis of Primary and Tertiary Alkyl Halides. Polar Effect IX
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When the Hammett-Taft equation log (k/k0) = ρq ?qi is applied to the solvolysis of the 3-substituted propyl bromides 6a-6i in ethanol/water 4:1 (v/v) log k correlates linearly with ?qI except in cases where R exerts an anchimetric effect.The reaction constant ρq for 6 is -0.12 and is typical for a nucleophilic solvent assisted ks process at a primary C-atom.The tertiary halides 1 and 3, however, which reacty with little or no nucleophilic solvent assistance, i.e. by kc processes, lead to larger ρq values of -0.71 and -1.14, respectively.The reacton constant ρq is therefore a sensitive gauge for charge development in the transition state for solvolysis of satured compounds.
- Grob, Cyril A.,Waldner, Adrian
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p. 2152 - 2158
(2007/10/02)
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- SYNTHESIS OF HIGHER ACETYLENIC ALCOHOLS
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The alkylation of 1-alkynes in various solvents was investigated, and the optimum conditions for the production of acetylenic alcohols were obtained.
- Kovalev, B. G.,Matveeva, E. D.,Stan, V. V.,Vovk, G. A.,Yudin, L. G.,Kost, A. N.
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p. 1728 - 1733
(2007/10/02)
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