- Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
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Chemoselective deoxygenation of carbonyls and alcohols using hydrogen by heterogeneous base-metal catalysts is crucial for the sustainable production of fine chemicals and biofuels. We report an aluminum metal-organic framework (DUT-5) node support cobalt(II) hydride, which is a highly chemoselective and recyclable heterogeneous catalyst for deoxygenation of a range of aromatic and aliphatic ketones, aldehydes, and primary and secondary alcohols, including biomass-derived substrates under 1 bar H2. The single-site cobalt catalyst (DUT-5-CoH) was easily prepared by postsynthetic metalation of the secondary building units (SBUs) of DUT-5 with CoCl2 followed by the reaction of NaEt3BH. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of CoII and AlIII centers in DUT-5-CoH and DUT-5-Co after catalysis. The coordination environment of the cobalt center of DUT-5-Co before and after catalysis was established by extended X-ray fine structure spectroscopy (EXAFS) and density functional theory. The kinetic and computational data suggest reversible carbonyl coordination to cobalt preceding the turnover-limiting step, which involves 1,2-insertion of the coordinated carbonyl into the cobalt-hydride bond. The unique coordination environment of the cobalt ion ligated by oxo-nodes within the porous framework and the rate independency on the pressure of H2 allow the deoxygenation reactions chemoselectively under ambient hydrogen pressure.
- Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
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supporting information
p. 9029 - 9039
(2021/06/28)
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- Aryl [a] indole [2,3 - the g] and quinolizine compound, preparation method thereof, pharmaceutical compositions and uses thereof
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The invention relates to an aryl [a] indole [2,3-g] quinolizine compound as well as a preparation method, a pharmaceutical composition and application thereof, and particularly relates to a aryl [a] indole [2,3-g] quinolizine compound with a novel structure as shown in a general formula (I) and a derivative, a preparation method and a pharmaceutical composition thereof and application of the aryl [a] indole [2,3-g] quinolizine compound in preparation of a drug for treating diseases related to alpha 1-adrenoreceptor and urinary system diseases, such as benign prostatic hyperplasia, uroschesis and bladder outlet obstruction, especially.
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Paragraph 0370; 0371
(2017/01/17)
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- Methyl Hydrazinocarboxylate as a Practical Alternative to Hydrazine in the Wolff-Kishner Reaction
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Herein we describe a facile protocol for the reduction of aromatic ketones and aldehydes to the corresponding methylene unit. The procedure involves isolation of a carbomethoxyhydrazone intermediate that is easily decomposed to the reduced product without the requirement for large quantities of pernicious hydrazine.
- Cranwell, Philippa B.,Russell, Andrew T.,Smith, Christopher D.
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supporting information
p. 131 - 135
(2015/12/26)
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- Benzyllithiums bearing aldehyde carbonyl groups. A flash chemistry approach
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Reductive lithiation of benzyl halides bearing aldehyde carbonyl groups followed by reaction with subsequently added electrophiles was successfully accomplished without affecting the carbonyl groups by taking advantage of short residence times in flow microreactors.
- Nagaki, Aiichiro,Tsuchihashi, Yuta,Haraki, Suguru,Yoshida, Jun-ichi
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supporting information
p. 7140 - 7145
(2015/07/01)
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- Boron-Catalyzed N-Alkylation of Amines using Carboxylic Acids
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A boron-based catalyst was found to catalyze the straightforward alkylation of amines with readily available carboxylic acids in the presence of silane as the reducing agent. Various types of primary and secondary amines can be smoothly alkylated with good selectivity and good functional-group compatibility. This metal-free amine alkylation was successfully applied to the synthesis of three commercial medicinal compounds, Butenafine, Cinacalcet. and Piribedil, in a one-pot manner without using any metal catalysts.
- Fu, Ming-Chen,Shang, Rui,Cheng, Wan-Min,Fu, Yao
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supporting information
p. 9042 - 9046
(2015/08/03)
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- Continuous-flow hydrogenation of olefins and nitrobenzenes catalyzed by platinum nanoparticles dispersed in an amphiphilic polymer
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A method for the flow hydrogenation of olefins and nitrobenzenes in a continuous-flow reactor containing platinum nanoparticles dispersed on an amphiphilic polystyrene-poly(ethylene glycol) resin (ARP-Pt) was developed. The hydrogenation of olefins and nitrobenzenes was completed within 31 seconds in the continuous-flow system containing ARP-Pt, giving the corresponding hydrogenated products in up to 99% yield with good chemoselectivity. Moreover, long-term (63-70 h) continuous-flow hydrogenation of styrene and nitrobenzene produced more than ten grams of ethylbenzene and aniline, respectively, without significant loss of catalytic activity. The flow hydrogenation system provides an efficient and practical method for the chemoselective reduction of olefins and nitrobenzenes. This journal is
- Osako, Takao,Torii, Kaoru,Tazawa, Aya,Uozumi, Yasuhiro
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p. 45760 - 45766
(2015/06/08)
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- Activity investigation of imidazolium-based ionic liquid as catalyst for friedel-crafts alkylation of aromatic compounds
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N-Methylimidazolium ionic liquids were synthesised from N-methylimidazole and 1-bromobutane by two-step method. The alkylation of benzene and other aromatic compounds through improved Friedel-Crafts reaction was investigated in these ionic liquids. The imidazolium-based ionic liquids showed both high activity and high selectivity for this reaction. In particular, remarkable enhancement of the catalytic effect of the imidazolium-based ionic liquids was observed for the ionic liquids containing the PF6- anion. The effects of various types of anions, ionic liquid dosage, reaction temperature and molar ratio of aromatic compound to 1-bromobutane/tertbutyl alcohol were explored using [Bmim]PF6 or its mixture with AlCl3 as catalyst. The synthesis yielded improved results over those obtained using either neat AlCl3 or other imidazolium-based ionic liquids as catalyst. The ionic liquids can also be recycled and reused in contrast to traditional solvent-catalyst systems.
- Cai, Mingjian,Wang, Xiuge
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p. 649 - 653
(2015/01/30)
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- Investigation of the aroma-active compounds formed in the maillard reaction between glutathione and reducing sugars
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Aroma-active compounds formed during the thermal reaction between glutathione (GSH) and reducing sugars were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-olfactometry (GC-O) with aroma extract dilution analysis (AEDA). Application of AEDA to glutathione Maillard reaction products (GSH MRPs) led to the identification of 19 aroma-active compounds in the thermal reaction of glutathione with glucose or fructose. In addition, the carbohydrate module labeling (CAMOLA) approach was also employed to elucidate the formation pathways for selected target sulfur aroma compounds, such as 5-methylthiophene-2-carbaldehyde and 3-methylthiophene-2-carbaldehyde, which have not been reported previously. The intact carbon skeleton of glucose via 3-deoxyhexosone is incorporated into 5-methylthiophene-2-carbaldehyde with the hydrogen sulfide of GSH. On the other hand, the formation of 3-methylthiophene2-carbaldehyde may occur via the recombination of a C-4 sugar fragment and mercaptoacetaldehyde.
- Lee, Sang Mi,Jo, Ye-Jin,Kim, Young-Suk
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experimental part
p. 3116 - 3124
(2011/08/05)
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- Catalytic transformations of alkylthiophenes
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The transformations of alkylthiophenes in the presence of amorphous aluminosilicate and decationated zeolite HNaY were studied. Substituted thiophenes with R = 2- and 3-Me, 2-Et, and 2-iso-Pr undergo dealkylation to thiophene with close rates, migration of the alkyl group from the 9α- to the β-position of the thiophene ring (or in the opposite direction with an elevated rate), and decomposition with H2S elimination. The dealkylation rate of 2-substituted thiophenes with a branched-chain radical (R = iso-Pr, terf-Bu) is much higher and the elimination rate with this radical is lower than those for normal-chain radicals; the isomerization step is virtually absent. Di-, tri-, and tetrasubstituted thiophenes with R = Et and iso-Pr undergo stepwise dealkylation, which is facilitated by an increase in the degree of substitution on the thiophene ring. Thiophene and its lower homologues can be obtained by the transformation of a mixture of high-molecular thiophenes. Copyright
- Mashkina,Chernov
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p. 209 - 215
(2007/10/03)
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- Initiation of thermal reactions of sulfur compounds by dialkyl selenides
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The use of diethyl selenide (20-40 mol %) as initiator in the gas-phase synthesis of thiophene from diethyl disulfide and acetylene increases the selectivity of the process and the yield of thiophene from 40 to 92%. As a result, this reaction becomes the most efficient preparative method for the synthesis of thiophene and also of selenophene which is formed in up to 70% yield. The complete conversion of both sulfur-and selenium-containing reagents is attained. Due to much different boiling points, thiophene and selenophene can readily be separated by rectification of the reaction mixture. Dialkyl selenides also initiate other thermal reactions of hydrogen sulfide and organic sulfides.
- Deryagina,Sukhomazova,Levanova,Shilkina,Korchevin
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p. 359 - 363
(2007/10/03)
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- Oligomerization of the Thiophene-Based p-Quinodimethanes 2,5-dihydrothiophene and 2-Ethylidene-5-methylene-2,5-dihydrothiophene
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Flash vacuum pyrolysis (FVP) of (5-methyl-2-thiophene-yl)methyl benzoate (8) produces in ca. 75% yield 2,5-dimethylene-2,3-dihydrothiophene, S-monomer (3). S-Monomer 3 is relatively stable dissolved in carbon disulfide-chloroform at -78°C. The structure of 3 is confirmed by its spectral properties. When a 0.17 M solution of S-monomer 3 was allowed to warm to room temperature, SS-dimer 5 ([2,2](2,5)thiophenophane, 14.7%), SSS-trimer 7 ([2,2,2](2,5)thiophenophane, 44.3%), and polymer were produced. A small amount ( 1%) of an SSSS-tetramer was detected by GC/MS. The mechanism proposed for the formation of these oligomers involves the combination of two molecules of 3 to give an intermediate diradical (11) that can close to form dimer 5 or react with additional molecules of 3 to form the higher oligomers. Evidence for the trapping of diradical 11 by 2,5-dimethylene-2,5-dihydrofuran (O-monomer 2) was obtained. Co-oligomerization of S-monomer 3 and O-monomer 2 gave four compounds containing the thiophene moiety: OS-dimer 16, SS-dimer 5, OSS-trimer 17, and SSS-trimer 7. Some OO-dimer 4 was produced but no OOO-trimer 6 was observed and only a trace of OOS-trimer 18 was detected. Additional support for the diradical mechanism was obtained from the study of the oligomerization of the methyl derivatives of 3, 2-ethylidene-5-methylene-2,5-dihydrothiophene (10, E and Z isomers), prepared by the FVP of (5-ethyl-2-thiophene-yl)methyl benzoate (9). Oligomerization of 10 gave several dimers and trimers including two acyclic dimers that are accounted for by intramolecular disproportionation.
- Trahanovsky, Walter S.,Miller, Deborah Louise,Wang, Yili
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p. 8980 - 8986
(2007/10/03)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS XXXV. THERMAL REACTIONS OF DI(1-PROPENYL) SULFIDE
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The thermolysis of dipropenyl sulfide in a flow-type system in an atmosphere of nitrogen at 450-540 deg C leads to propenethiol, thiophene, methylthiophenes, and 2-ethylthiophene.The formation of the thiophene derivatives results from intramolecular radical cyclization of the initial sulfide.Dimethyl selenide (5-10 mole percent) substantially accelerates the thermolysis of dipropenyl sulfide, and the yield of 2-ethylthiophene at 450-480 deg C is increased appreciably.The high-temperature reactions of di(1-propenyl) sulfide with 2-halogenothiophenes and acetylene confirm that the propenethiol and thiophene derivatives are formed in parallel during the thermolysis of dipropenyl sulfide.
- Ostroukhova, L. A.,Deryagina, E. N.,Korchevin, N. A.,Musorin, G. K.,Amosova, S. V.,Voronkov, M. G.
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p. 301 - 305
(2007/10/02)
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- Synthesis of some Thiophenium Bis(t-butoxycarbonyl)methylides
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Thiophene derivatives react with di-t-butyl diazomalonate in the presence of rhodium(II) carboxylates to yield thiophenium bis(t-butoxycarbonyl)methylides.Rhodium(II) hexanoate is a more efficient catalyst than rhodium(II) acetate, shortening reaction times and increasing yields of the ylides.Series of 2-halogeno-, 2-alkyl-, 2-benzyl-5-halogeno-, and 2-benzyl-5-alkyl-thiophenium ylides are described.Whilst 2-methyl-, 2-ethyl-, and 2-isopropyl-thiophenes readily form the ylides in good yield, 2-t-butylthiophene appears to undergo further reaction to yield 1,3-bis-t-butoxycarbonyl-2-(3-t-butyl-6,6-bis-t-butoxycarbonyl-2-thioniabicyclohex-3-en-2-yl)methanide (2) whose structure has been confirmed by X-ray crystallography.
- Bowles, Timothy,Jones, Ray,Porter, Alexander E. A.,Rechka, Josef A.,Rzepa, Henry S.,Williams, David J.
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p. 1023 - 1028
(2007/10/02)
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- STABLE HETEROARENIUM IONS-IX. DISPROPORTIONATION OF ALKYLTHIOPHENIUM IONS AND ITS USE FOR THE SYNTHESIS OF 2,4-DIALKYLTHIOPHENES
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A number of isopropyl and ethyl substituted thiophenium ions has been generated by the alkylation of thiophene and protonation of alkylthiophenes.Disproportionation of these ions has been studied at room temperature and at the b.p. of 1,2-dichloroethane used as a solvent while preparing the ions. 2,4-Diethylthiophene has been prepared from its mixture with the 2,5-isomer by disproportionation of the 2,5-diethyl-2H-thiophenium ion.
- Belen'kii, L. I.,Yakubov, A. P.
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p. 759 - 762
(2007/10/02)
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- Reactions of Thiophene and Alkylthiophenes in Glow Discharge
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The glow discharge reaction of thiophene is shown to produce thioketene and carbon monosulfide along with other gaseous products.The dominant liquid product is ethynylthiophene.Methylthiophenes and especially dimethylthiophenes produce benzene as one of the major liquid products.
- Skramstad, Jan,Chaudhry, Mohammed Shoaib,Garvang, Arne
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p. 509 - 512
(2007/10/02)
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- Sulfonation of aromatic compounds in the presence of solvents
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A process for the sulfonation of aromatic compounds wherein an aromatic substance consisting of one or more aromatic compounds susceptible to the action of sulfur trioxide is formed into a reactant by admixture with one or more organic liquids, substantially inert to sulfur trioxide under the conditions of the process, which reactant is brought to boiling at a temperature not greater than 100° C under a pressure of from 0.1 mm Hg to atmospheric pressure, gaseous sulfur trioxide is introduced thereinto thereby causing it to continue to boil, the component or components of the reactant thus volatilized is or are reconverted to liquid in a heat-exchanger and recycled to the reaction chamber, and the pressure in the reaction chamber and the rate at which the gaseous sulfur trioxide is introduced into the reactant are controlled so as to ensure that there is always present in the reaction chamber an amount of volatilizable matter exceeding that amount volatilizable by the heat of reaction of the aromatic substance present in the reaction chamber with the gaseous sulfur trioxide in contact with said aromatic substance and that the temperature of the reaction mixture is a temperature of 100° C or below.
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