- Bromotrimethylsilane as a selective reagent for the synthesis of bromohydrins
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Bromotrimethylsilane (TMSBr) is a very efficient reagent in the solvent-free conversion of glycerol into bromohydrins, useful intermediates in the production of fine chemicals. As glycerol is a relevant by-product in biodiesel production, TMSBr has been also tested as a mediator in transesterification in acidic conditions, providing FAME from castor oil in good yields, along with bromohydrins from glycerol. Subsequently the glycerol conversion was optimized and depending on the reaction conditions, glycerol can be selectively converted into α-monobromohydrin (1-MBH) or α,γ-dibromohydrin (1,3-DBH) in very good yields. This journal is
- Giomi, Donatella,Salvini, Antonella,Ceccarelli, Jacopo,Brandi, Alberto
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p. 14453 - 14458
(2021/05/19)
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- Preparation method of 3-hydrazino-5-morpholinomethyl-2-oxazolidinone
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The invention provides a preparation method of 3-hydrazino-5-morpholinomethyl-2-oxazolidinone, and belongs to the technical field of chemical synthesis. The preparation method comprises the followingsteps: carrying out a cyclization reaction on 1-Boc protective hydrazine-3-morpholine-2-propanol and a carbonic ester substance to obtain 3-Boc protective hydrazine-5-morpholinomethyl-2-oxazolidinone;and finally hydrolyzing to obtain the AMOZ. The chemical structural formula of the 1-Boc protective hydrazine-3-morpholine-2-propanol is shown in the specification, the chemical structural formula ofthe 3-Boc protective hydrazine-5-morpholinomethyl-2-oxazolidinone is shown in the specification, and the chemical structural formula of the AMOZ is shown in the specification; and the carbonic estersubstance contains at least one of diethyl carbonate, dimethyl carbonate, di-tert-butyl decarbonate, and dipropyl carbonate. The method is simple in synthetic route, the AMOZ is synthesized by adopting a one-pot method, and the catalyst is used in the preparation process, so that the loss in the synthesis process is greatly reduced, the synthesis yield and the recovery rate are relatively high; and the method is suitable for mass production.
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Paragraph 0093-0094
(2020/07/12)
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- Expeditious Syntheses to Pharmochemicals 1,3-Dihydroxyacetone, 1,3-Dichloro-, 1,3-Dibromo- And 1,3-Diiodoacetone from Glycerol 1,3-Dichlorohydrin Using Homogenous and Heterogenous Medium
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New efficient and reproductive routes to production of 1,3-dihydroxyacetone (1), 1,3-dichloroacetone (6), 1,3-dibromoacetone (7) and 1,3-diiodoacetone (8) from glycerol 1,3-dichlorohydrin (3) were developed. The synthesis of 1 was processed in three steps from glycerol 2 (1,3-selective chlorination of 2 to 3, oxidation of 3 to 6 and subsequent di-hydroxylation) in 51% overall yield. On the other hand, 7 and 8 were produced from 3, via a trans-bromination and trans-iodination, respectively, followed by oxidation and hydroxylation steps, in 38-52% overall yield. It was used homogeneous media with different reagents (HCl/AcOH, pyridinium chlorochromate (PCC), PCC-HIO4) and heterogeneous media with reagents supported on polymer resins such as Amberlyst A26-HCrO4– form, PV-PCC (polyvinyl-pyridinium chlorochromate) and Amberlyst A26-OH– form or reagents supported on alumina such as KI/Al2O3, KBr/Al2O3, in solvent free conditions.
- Pereira, Vera Lúcia P.,da Silva, Fernanda Priscila N. R.,da Silva, Sara R. B.,dos Santos, Priscila F.
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p. 1725 - 1731
(2020/10/09)
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- Synthesis of Functionalized Cyclic Carbonates by One-Pot Reactions of Carbon Dioxide, Epibromohydrin, and Phenols, Thiophenols, or Carboxylic Acids Catalyzed by Ionic Liquids
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The one-pot reactions of CO2, epibromohydrin, and phenols, thiophenols, or carboxylic acids catalyzed by 1-butyl-3-[(3-hydroxyphenyl)methyl]imidazolium bromide were investigated. Three kinds of cyclic carbonates with ether, thioether, or ester groups were synthesized under mild reaction conditions in good-to-high yields. Reaction-mechanism studies indicated that the proton exchange between the alkoxide formed through the ring-opening reaction of epibromohydrin with 1-bromo-3-phenoxy-2-propanol plays a crucial role in this synthetic route. The catalyst 1-butyl-3-[(3-hydroxyphenyl)methyl]imidazolium bromide was transformed to the corresponding cyclic-carbonate-functionalized ionic liquid during the reaction. This transformation did not affect its catalytic performance in the reaction.
- Wu, Shi,Zhang, Yongya,Wang, Binshen,Elageed, Elnazeer H. M.,Ji, Liangzheng,Wu, Haihong,Gao, Guohua
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supporting information
p. 753 - 759
(2017/02/05)
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- For the preparation of intermediate crystallinity of, its synthetic method, intermediate and use thereof
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The present invention relates to a novel intermediate for preparation of bruguiesulfurol with II-type diabetes resisting activity, a synthetic method, an intermediate and use thereof, and a bruguiesulfurol preparation method. The bruguiesulfurol preparation method has the advantages of new synthetic route, simple operation, high yield and good safety, is suitable for industrialized production, and can solve the problem that in the prior art the compound only can be prepared form mangrove forest plant extracts by very-low-efficiency extraction and separation.
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Paragraph 0048; 0049; 0050
(2017/06/10)
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- Synthesis of Di-, Tri-, and tetrasubstituted oxetanes by rhodium-catalyzed O-H insertion and C-C bond-forming cyclization
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Oxetanes offer exciting potential as structural motifs and intermediates in drug discovery and materials science. Here an efficient strategy for the synthesis of oxetane rings incorporating pendant functional groups is described. A wide variety of oxetane 2,2-dicarboxylates were accessed in high yields, including functionalized 3-/4-aryl-and alkyl-substituted oxetanes and fused oxetane bicycles. Enantioenriched alcohols provided enantioenriched oxetanes with complete retention of configuration. The oxetane products were further derivatized, while the ring was maintained intact, thus highlighting their potential as building blocks for medicinal chemistry.
- Davis, Owen A.,Bull, James A.
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supporting information
p. 14230 - 14234
(2015/02/19)
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- The first synthesis of natural disulfide bruguiesulfurol and biological evaluation of its derivatives as a novel scaffold for PTP1B inhibitors
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Bruguiesulfurol (1), a cyclic 4-hydroxy-dithiosulfonate isolated from mangrove plant Bruguiera gymnorrhiza, was concisely synthesized for the first time in four steps, and a series of its synthetic derivatives were evaluated for in vitro inhibitory effects on PTP1B and related PTPs. Some derivatives were found to have improved pharmacological profile compared with hit 1. Among them, 5a showed the potent selectivity towards PTP1B over other PTPs, including TCPTP, and 7j exhibited the strongest PTP1B inhibitory activity with an IC 50 value of 4.54 μM.
- Chen, Jing,Jiang, Cheng-Shi,Ma, Wen-Quan,Gao, Li-Xin,Gong, Jing-Xu,Li, Jing-Ya,Li, Jia,Guo, Yue-Wei
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supporting information
p. 5061 - 5065
(2013/09/12)
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- Monobromoborane-dimethyl sulfide - A highly promising reagent for the regio- and chemoselective brominative cleavage of terminal epoxides into vicinal bromohydrins
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Monobromoborane?dimethyl sulfide (BH2Br?SMe2) is a highly regio- and chemoselective reagent useful for the brominative cleavage of the epoxy moiety into bromohydrins in the presence of alkenes, alkynes, ethers, acetals, ketals, and acetonides at 0°C, besides being an excellent hydroborating reagent. Several reactive functional groups, such as chloride, ketones, esters, nitriles, nitros, and thioethers, have been accommodated during such transformations. Although the reduction of acetophenone was completely suppressed at ?25°C, 4-chlorobenzaldehyde still underwent 12?13% reduction of an aldehydic group. CSIRO 2007.
- Roy, Chandra D.,Brown, Herbert C.
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p. 139 - 145
(2008/02/11)
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- Dimethoxyboron bromide - A new, efficient, regio- and chemoselective reagent for the conversion of terminal epoxides into bromohydrins
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Dimethoxyboron bromide, (MeO)2BBr, easily prepared in excellent yield from boron tribromide and trimethyl borate, is a new, efficient, regio- and chemoselective reagent useful for the halogenative cleavage of compounds containing epoxy groups into vicinal bromohydrins in the presence of ether, acetal, ketal, N-oxide, and sulfoxide groups, at low temperatures (-78°C).
- Roy, Chandra D.,Brown, Herbert C.
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p. 639 - 641
(2007/10/03)
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- Synthesis of cationic cardiolipin analogues
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An approach was developed to synthesize a new class of cationic cardiolipin analogues containing two quaternary ammonium groups with tetra alkyl groups retaining "glycerol" moiety, the central core of the molecule. Cationic cardiolipin analogues were modified via introduction of either two or four oxyethylene groups to enhance the solubility in polar solvents. These newly synthesized cationic cardiolipin analogues can be applied to a broad range of drug delivery systems such as transfection reagents.
- Kasireddy, Krishnudu,Ali, Shoukath M.,Ahmad, Moghis U.,Choudhury, Sreeti,Chien, Pei-Yu,Sheikh, Saifuddin,Ahmad, Imran
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p. 345 - 362
(2008/02/01)
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- Enzymatic dynamic kinetic resolution of epihalohydrins
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The haloalcohol dehalogenase from Agrobacterium radiobacter AD1 catalyses the reversible ring closure of vicinal haloalcohols to produce epoxides and halides. In the ring opening of epoxides, nonhalide nucleophiles such as N 3- are accepted. The enantioselective irreversible ring opening of an epihalohydrin by N3-, combined with racemisation caused by a reversible ring opening by a halide, resulted in an enzymatic dynamic kinetic resolution yielding optically active (S)-1-azido-3-halo-2-propanol. With epichlorohydrin as a substrate, the rate of ring opening by N3- was higher than the rate of racemisation, resulting in a mixed kinetic resolution and dynamic kinetic resolution. With epibromohydrin as the substrate, the racemisation rate was higher than the rate of ring opening, resulting in an efficient dynamic kinetic resolution. By optimising the pH of the medium and the concentrations of N 3- and Br-, the product (S)-1-azido-3-bromo-2- propanol could be obtained in 84% yield and 94% ee. An (R)-enantiomer selective ring closure of this bromoalcohol, catalysed by the same enzyme, caused a simultaneously occurring kinetic resolution, yielding when the conversion progressed, an increase in enantiopurity of (S)-1-azido-3-bromo-2-propanol to >99% ee with a yield of 77%. This compound and the ring-closed product glycidyl azide can be used as chiral synthetic building blocks.
- Lutje Spelberg, Jeffrey H.,Tang, Lixia,Kellogg, Richard M.,Janssen, Dick B.
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p. 1095 - 1102
(2007/10/03)
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- NaIO4-Mediated Selective Oxidative Halogenation of Alkenes and Aromatics Using Alkali Metal Halides
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(Equation presented) NaIO4 oxidizes alkali metal halides efficiently in aqueous medium to halogenate alkenes and aromatics and produce the corresponding halo derivatives in excellent regio and stereoselectivity. The system also demonstrates the asymmetric version of bromo hydroxylation using β-cyclodextrin complexes, resulting in moderate ee.
- Dewkar, Gajanan K.,Narina, Srinivasarao V.,Sudalai, Arumugam
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p. 4501 - 4504
(2007/10/03)
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- Conversion of epoxides into halohydrins with elemental halogen catalyzed by thiourea
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A highly regioselective method for the synthesis of β-iodohydrins and β-bromohydrins by the direct ring opening of epoxides with elemental halogen in the presence of thiourea is described. This method occurs under neutral and mild conditions with high yields in various solvents even when sensitive functional groups are present.
- Sharghi, Hashem,Eskandari, Mohammad Mehdi
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p. 8509 - 8514
(2007/10/03)
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- Studies into reactions of N-methylmorpholine-N-oxide (NMMO) and its hydrates with cyanuric chloride
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The course of the reaction between N-methylmorpholine-N-oxide (NMMO, 1a) and cyanuric chloride (2) is strictly dependent on the hydrate water content of the amine oxide. In solid phase, both substances undergo an explosion-like, extremely exothermic reaction. In solution, this process becomes controllable and leads to a quantitative degradation of NMMO into morpholine and formaldehyde, with 2 only acting as an inducing agent. The reaction can be conducted in a way that a clean deoxygenative demethylation is achieved. The monohydrate of NMMO (1b) is quantitatively converted into N-methylmorpholine and hypochlorous acid by the action of 2. This conversion can be used in synthesis either to deoxygenate tertiary amine N-oxide monohydrates, or to produce chlorohydrins in non-aqueous, organic media in superior yields. The semisesquihydrate of NMMO (1c) reacts with 2 under consumption of water until non-hydrated NMMO is present, which is then further converted into morpholine and HCHO, as in the case of 1a being directly employed as the starting material.
- Rosenau, Thomas,Potthast, Antje,Kosma, Paul
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p. 9809 - 9815
(2007/10/03)
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- Conversion of epoxides to halohydrins with elemental halogen catalyzed by phenylhydrazine
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The highly regioselective method for the synthesis of β-iodohydrins and β-bromohydrins by the direct ring opening of 1,2-epoxides with elemental halogen in the presence of phenylhydrazine is described. This method occurs under neutral and mild conditions with high yields in various aprotic solvents even when sensitive functional groups are present.
- Sharghi, Hashem,Eskandari, Mohammad Mehdi
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p. 1519 - 1522
(2007/10/03)
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- Polymer-supported chiral Co(salen) complexes: Synthetic applications and mechanistic investigations in the hydrolytic kinetic resolution of terminal epoxides
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This paper describes the synthesis of polystyrene- and silica-bound chiral Co(salen) complexes and their application in asymmetric catalysis. A general method for the covalent attachment of salen complexes to both types of support has been devised, and the corresponding immobilized cobalt derivatives are shown to be efficient and highly enantioselective catalysts for the hydrolytic kinetic resolution (HKR) of terminal epoxides. These systems provide practical solutions to certain technical difficulties associated with the isolation of reaction products from the HKR. Removal of the supported catalyst by filtration and repeated recycling is demonstrated with no loss of reactivity or enantioselectivity. The enantioselective addition of phenols to terminal epoxides mediated by this catalyst system provides a facile, high-yielding synthesis of the corresponding enantioenriched aryl ethers. The immobilized catalysts have been adapted to a continuous flow process for the generation of reaction products in high yield and ee, requiring only very simple techniques for product purification. The mechanism by which these catalysts perform highly efficient and enantioselective epoxide ring opening has been addressed using a silica- bound Co(salen) complex. A dramatic correlation between the degree of catalyst site-isolation and reaction rate has been observed, consistent with a cooperative bimetallic mechanism in these reactions.
- Annis, D. Allen,Jacobsen, Eric N.
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p. 4147 - 4154
(2007/10/03)
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- Synthesis of Dibromohydrins from Glycerol by Using an Ion Exchange Resin as Catalyst
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Bromination of glycerol by 48percent hydrobromic acid in the presence of an acid ion exchange resin (C264 or A19) led to the formation of a mixture of 1,3- and 2,3-dibromohydrins in a yield of around 70percent.The side products were essentially brominated polyglycerols.
- Bouillaud, Alain,Dargelos, Marianne,Borredon, Marie-Elisabeth
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p. 2123 - 2128
(2007/10/02)
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- A New and Efficient One-Pot Preparation of Alkyl Halides From Alcohols
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Primary alkanols and 2-alkenols are converted into the corresponding halides in high yield by a one-pot, two-step reaction via transformation into intermediate trifluoroacetates followed by nucleophilic substitution with lithium halides.
- Camps, Francisco,Gasol, Vicens,Guerrero, Angel
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p. 511 - 512
(2007/10/02)
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- Preparation of (+)- and (-)-2,3-Dibromo-1-propanols
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The enantiomers of 2,3-dibromo-1-propanol were obtained by diazotization of the diastereomeric d-tartrate salts of 2,3-dibromopropylamine.The products of the reaction contained approximately 13percent of the secondary alcohol 1,3-dibromo-2-propanol which was separated by either column chromatography on silica gel or preparative GLC to obtain the primary alcohols (+)-2,3-dibromo-1-propanol (26D +13.8 deg) and (-)-2,3-dibromo-1-propanol (24D -12.8 deg).NMR and EI mass spectra of the primary and secondary dibromopropanols clearly distinguished the structuralisomers from one another.The optical isomers will be used to examine possible stereoselective differences in mutagenic potency, since 2,3-dibromo-1-propanol is a mutagenic metabolite of the potent mutagen and carcinogen tris(2,3-dibromopropyl) phosphate.
- Huitric, Alain C.,Gordon, W. Perry,Nelson, Sidney D.
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p. 474 - 475
(2007/10/02)
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