- Phase-vanishing reactions that use fluorous media as a phase screen. Facile, controlled bromination of alkenes by dibromine and dealkylation of aromatic ethers by boron tribromide
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In fluorous triphasic reactions, such as bromination of alkenes by dibromine and dealkylation of aromatic ethers by boron tribromide, the middle fluorous phase acts as a liquid membrane permitting passive transport of the reagents at the bottom to the top layer involving the substrates, thereby regulating the reactions. Copyright
- Ryu, Ilhyong,Matsubara, Hiroshi,Yasuda, Shinji,Nakamura, Hiroyuki,Curran, Dennis P.
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- VALISA: A new procedure for total lineshape analysis of NMR spectra. Conformational analysis of trans-1,2-dibromocyclopentane
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A new strategy of total lineshape analysis of the multiplet structure of NMR spectra was proposed and a VALISA program was developed to implement the computational procedure. Evaluation of the new technique taking a solution of several test problems and the complete analysis of the 1H NMR spectrum of trans-1,2-dibromocyclopentane as examples showed its high efficiency. Using a complete set of vicinal spin-spin coupling constants, detailed conformational analysis of this molecule was carried out and a more correct model for the description of conformational interconversions of the five-membered cycles was proposed. Conformational behavior of trans-1,2-dibromocyclopentane molecule can be reasonably described assuming large-amplitude molecular vibrations along a sector of the pseudorotation path, containing mostly diequatorial conformations.
- Zubkov,Golotvin,Chertkov
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- A Highly Efficient Method for the Bromination of Alkenes, Alkynes and Ketones Using Dimethyl Sulfoxide and Oxalyl Bromide
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The pairing of DMSO and oxalyl bromide is reported as a highly efficient brominating reagent for various alkenes, alkynes and ketones. This bromination approach demonstrates remarkable advantages, such as mild conditions, low cost, short reaction times, provides excellent yields in most cases and represents a very attractive alternative for the preparation of dibromides and α-bromoketones.
- Ding, Rui,Li, Jiaqi,Jiao, Wenyi,Han, Mengru,Liu, Yongguo,Tian, Hongyu,Sun, Baoguo
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p. 4325 - 4335
(2018/11/21)
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- Method for preparing o-dibromo compounds from olefins
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The invention relates to a method for preparing o-dibromo compounds from olefins, and the structural formulae of the o-dibromo compounds are as follows. The method comprises the following steps: dropwise adding a dichloromethane solution of dimethyl sulfoxide (1.5 equiv) into a dichloromethane solution of oxalyl bromide (1.5 equv) at a temperature of -10 DEG C, then dropwise adding a raw materialolefin, and then recovering the temperature to room temperature or carrying out heating to 30-40 DEG C, carrying out a reaction to obtain the corresponding o-dibromo compounds, wherein the yield is ina range of 79-97%.
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Paragraph 0012; 0013
(2018/09/28)
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- A method for the treatment of tumor cell proliferative diseases of platinum (II) compound
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Disclosed are a platinum compound with the leaving group malonic derivative "2" position substituent containing a primary amino, a secondary amino, a tertiary amino, and a quaternary amino, as well as pharmaceutically acceptable salt, preparation method thereof, and pharmaceutical composition containing the compound. Also disclosed are uses of the compound for treating cell proliferative diseases, particularly cancers. The platinum compound of the present invention has the high water solubility and the low toxicity.
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Paragraph 0249; 0256; 0257; 0258; 0259
(2018/01/11)
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- PLATINUM COMPOUND OF MALONIC ACID DERIVATIVE HAVING LEAVING GROUP CONTAINING AMINO OR ALKYLAMINO
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Disclosed are a class of platinum compounds of malonic acid derivatives having a leaving group containing an amino or alkylamino, and pharmaceutically acceptable salt thereof, preparation method thereof and pharmaceutical composition containing the compou
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Paragraph 0171
(2015/11/16)
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- PLATINUM COMPOUND HAVING AMINO OR ALKYLAMINO-CONTAINING SUCCINIC ACID DERIVATIVES AS LEAVING GROUP, PREPARTION METHOD THEREOF, AND USE THEREOF
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Disclosed are a category of platinum compounds having amino- or alkylamino-containing succinato derivatives as leaving group, or pharmaceutically acceptable salts thereof, preparation method thereof, and medicinal compositions containing the compounds. Also disclosed is a use of the compounds in treating cell proliferative diseases, especially cancers. The platinum compounds of the present invention have high water solubility and small toxic side effect.
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Paragraph 0278; 0279
(2014/12/09)
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- Revisiting the bromination of c-h bonds with molecular bromine by using a photo-microflow system
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The photobromination of C-H bonds by using molecular bromine was reinvestigated under microfluidic conditions. The continuous-flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated products with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide group was achieved without any decomposition. Go with the (micro)flow: Photobromination of C-H bonds by using molecular bromine under microfluidic conditions has been investigated (see scheme). The continuous-flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated compounds with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide group was achieved without any decomposition.
- Manabe, Yoshiyuki,Kitawaki, Yuriko,Nagasaki, Masahiro,Fukase, Koichi,Matsubara, Hiroshi,Hino, Yoshiko,Fukuyama, Takahide,Ryu, Ilhyong
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supporting information
p. 12750 - 12753
(2015/03/30)
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- Direct sustainable bromination of alkenes in aqueous media and basic ionic liquids
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Electron-rich and electron-poor alkenes have been dibrominated using a rapid and sustainable procedure. The reactions were conducted in aqueous medium and basic ionic liquids which catalyzed the direct addition of bromine. The protocol leads to remarkable results, high yields under mild conditions, complete chemo- and stereo-selectivity and allows the recycling of ionic liquids, reducing costs, and environmental impact.
- Primerano, Patrizia,Cordaro, Massimiliano,Scala, Angela
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p. 4061 - 4063
(2013/07/25)
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- A bimetallic palladium(II) catalyzed synthesis of 1,2-dibromo compounds
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A bimetallic palladium(II) catalyst containing a triketone ligand and a bridging dinitrogen ligand oxidizes aromatic and cyclic aliphatic olefins in bromide-containing aqueous-THF to 1,2-dibromo compounds and bromohydrins. With aromatic olefins, the 1,2-dibromo products were obtained in a 70-80% yield and the bromohydrins in a 10-15% yield; this observation is opposition to that obtained in chloride containing medium where the chlorohydrin product predominates. The oxidation of 2,3-dihydrofuran gave trans-2,3- dibromotetrahydrofuran, 3-oxotetrahydrofuran, and 3-bromo-2- hydroxytetrahydrofuran in relative yields of 75%, 15%, and 10%, respectively. On the other hand, the oxidation of cyclopentene and cyclohexene affords only trans-1,2-dibromo products in about 90% yield. The stereochemistry is consistent with an anti-at-tack of bromide followed by decomposition involving attack of bromide from the coordination sphere of the Pd(II). The procedure outlined here is a convenient method for the one step synthesis of 1,2-dibromides.
- Qaseer
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- Selective conversion of epoxides to vic-halo alcohols and symmetrical or unsymmetrical dihalides by triphenylphosphine/2,3-dichloro-5,6-dicyano-1,4- benzoquinone (DDQ) in the presence of quaternary ammonium halides
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A new method is described for the efficient and selective conversion of epoxides to vic-halo alcohols or symmetrical and unsymmetrical dihalides using PPh3/DDQ/R4NX (X = Cl, Br, I) as a mixed-reagent system.
- Iranpoor, Nasser,Firouzabadi, Habib,Aghapour, Ghasem,Nahid, Azarmidokht
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p. 1885 - 1891
(2007/10/03)
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- Bromination of Alkenes in Acetonitrile. A Rate and Product Study
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The reaction of simple alkenes and aryl alkenes with molecular bromine in damp MeCN occurred with solvent incorporation to give 2-bromo-1-(N-acetylamino)alkanes, 2-methyloxazolines, 2-acetoxyalkylamine hydrobromides, and 2-(N-acetylamino) alcohols.These products arose by the transformation of initially formed 2-bromo-1-(N-acetylamino)alkanes obtained by MeCN attack on bromonium or bromocarbonium ions to give nitrilium tribromide salts.These reacted with water to give 2-bromo-1-(N-acetylamino)alkanes.The kinetic profile of the reaction showed a very fast initial reaction of the alkene and Br2 to yield the nitrilium tribromide, followed by a much slower reaction of Br3(1-) with the alkene.The incorporation of MeCN was Markovnikov and stereospecifically anti.The degree to which incorporation of solvent occurred depended upon the alkene structure and the initial reagent concentrations.A rationalization for the observed chemoselectivity and its dependence on the reaction conditions is offered.
- Bellucci, Giuseppe,Bianchini, Roberto,Chiappe, Cinzia
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p. 3067 - 3073
(2007/10/02)
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- QUESTION OF REVERSIBLE FORMATION OF BROMONIUM IONS DURING THE COURSE OF ELECTROPHILIC BROMINATION OF OLEFINS. 1. FORMAL TRANSFER OF Br + TO SCAVENGER OLEFINS FROM THE SOLVOLYTICALLY GENERATED BROMONIUM IONS OF CYCLOHEXENE AND CYCLOPENTENE.
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trans-2-Bromo-1- left bracket ((4-bromophenyl)sulfonyl)oxy right bracket cyclohexane and -cyclopentane (1 and 2), when solvolyzed at 75 degree C in glacial acetic acid containing Br** minus and a scavenger olefin (cyclopentene for 1 and cyclohexane for 2) generate free molecular Br//2 as is evidenced by the formation of crossed products. 1 is more prone to yield crossed product than is 2. In the absence of added Br** minus , the amount of crossed product formed in the solvolysis is small. The results are interpreted in terms of competitive Br** minus capture of the intermediate bromonium ions produced during the course of solvolysis at Br** plus and carbon, the latter event leading to trans dibromide products of the starting material, while the former event generates Br//2 and olefins. The results of these experiments, when applied to electrophilic Br//2 addition to alkenes, strongly suggest that the intermediate bromonium ions are formed reversibly.
- Brown,Gedye,Slebocka-Tilk,Buschek,Kopecky
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p. 4515 - 4521
(2007/10/02)
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- Stereospecific trans-elimination of 2-alkoxy- and 2-cycloalkoxytropones to alkenes and cycloalkenes
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The title compounds undergo thermal fragmentation to tropolones and alkenes and cycloalkenes.Product distribution and kinetic analyses of specifically labelled deuterio compounds establish the process to be a concerted electrocyclic reaction.
- Takeshita, Hitoshi,Mametsuka, Hiroaki
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p. 2035 - 2040
(2007/10/02)
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- One-pot Conversions of Amines into Olefins via Non-isolated Pyridinium Intermediates
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Secondary alkyl primary amines are converted by the pyrylium salt (1) directly at 20 deg C into olefins via the corresponding secondary carbenium ions.Isomeric olefin mixtures are elucidated and result from carbenium ion rearrangements.
- Katritzky, Alan R.,Lloyd, Jeremy M.
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p. 2347 - 2352
(2007/10/02)
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- Three Component Reactions XI. Bromochlorination of Cyclopentene in the Presence of Alcohols
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The product composition of reaction mixtures after the addition of bromochlorine to cyclopentene in the presence of several alcohols was determined by GLC in dependence of the molar relations, the temperature and the order of addition.A comparison with the chlorination and bromination is given.The yields of three component products increase in the order bromination-bromochlorination-chlorination and decrease from primary to tertiary alcohols.
- Beger, J.,Thielemann, C.
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p. 809 - 815
(2007/10/02)
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- Radical Reactions of Bicyclopentane
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The photochemical reactions of bicyclopentane with bromine, bromotrichloromethane, t-butyl hypochlorite, di-t-butyl peroxide, and N-bromosuccinimide have been investigated.Trichloromethyl, t-butoxyl, and succinimidyl radicals abstract hydrogen from the C4 ring.The expected bicyclopentyl radicals were not detected and if they are discrete intermediates they must rearrange by fission of the C(1)-C(4) bond common to the two rings to form cyclopent-3-enyl radicals.The e.s.r. spectrum of the latter radicals was obtained.Bromine (and chlorine) atoms may abstract hydrogen, but their major pathway involves attack at the bridgehead carbon atoms in an SH2 reaction with fission of the C(1)-C(4) bond to give 3-halogenocyclopentyl radicals.
- Jamieson, Campbell,Walton, John C.,Ingold, Keith U.
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p. 1366 - 1371
(2007/10/02)
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