نتایج جستجو برای: bromination

تعداد نتایج: 805  

2014
Yating Zhao Zhe Li Chao Yang Run Lin Wujiong Xia

A mild and efficient methodology for the bromination of phenols and alkenes has been developed utilizing visible light-induced photoredox catalysis. The bromine was generated in situ from the oxidation of Br(-) by Ru(bpy)3 (3+), both of which resulted from the oxidative quenching process.

Journal: :Molecules 2013
Jyotirmoy Maity Roger Stromberg

An efficient and facile strategy has been developed for bromination of nucleosides using sodium monobromoisocyanurate (SMBI). Our methodology demonstrates bromination at the C-5 position of pyrimidine nucleosides and the C-8 position of purine nucleosides. Unprotected and also several protected nucleosides were brominated in moderate to high yields following this procedure.

2014
Vilas Venunath Patil Ganapati Subray Shankarling

A new protocol for the oxidative bromination of aminoanthracene-9,10-dione, which is highly deactivated towards the electrophilic substitution is investigated. The peracid, nonanebis(peroxoic acid), possesses advantages such as better stability at room temperature, it is easy to prepare and non-shock sensitiv as compared to the conventional peracids. The present protocol has a broad scope for t...

Journal: :Dalton transactions 2008
Manoja K Samantaray Keliang Pang Mobin M Shaikh Prasenjit Ghosh

An unique long-range 1,7-bromination reaction is observed in gold(III) complexes of N-(aryl)imino functionalized N-heterocyclic carbene with the bromination occurring at two different carbon (sp2 and sp3) centers spatially separated by ca. 6.4 A but existing in extended conjugation to each other. In particular, the unusual distant 1,7-brominated gold(III) complexes [1-R-3-{N-(p-bromo-2,6-di-i-p...

Journal: :Tetrahedron letters 2012
Ramanjaneyulu Rayala Stanislaw F Wnuk

Treatment of the protected and unprotected nucleosides with 1,3-dibromo-5,5- dimethylhydantoin in aprotic solvents such as CH(2)Cl(2), CH(3)CN, or DMF effected smooth bromination of uridine and cytidine derivatives at C-5 of pyrimidine rings as well as adenosine and guanosine derivatives at C-8 of purine rings. Addition of Lewis acids such as trimethylsilyl trifluoromethanesulfonate enhanced ef...

2007
Linda Vaisman Gad Marom Jang-Kyo Kim

The graphite nanoplatelets (GNP) were treated by vapor-phase bromination. The increase in weight and atomic concentration of Br indicated the bromine uptake. The intercalation of Br between graphene layers of GNP was confirmed by the X-ray diffraction result, showing an increase in the interlayer spacing from 3.342 Å to 3.361 Å. Two types of bonds between C and Br were introduced simultaneously...

Journal: :Molecules 2015
Tushar R Mahajan Mari Eknes Ytre-Arne Pernille Strøm-Andersen Bjørn Dalhus Lise-Lotte Gundersen

The human 8-oxoguanine DNA glycosylase OGG1 is involved in base excision repair (BER), one of several DNA repair mechanisms that may counteract the effects of chemo- and radiation therapy for the treatment of cancer. We envisage that potent inhibitors of OGG1 may be found among the 9-alkyl-8-oxoguanines. Thus we explored synthetic routes to 8-oxoguanines and examined these as OGG1 inhibitors. T...

Journal: :Organic & biomolecular chemistry 2009
Johannes E M N Klein Helge Müller-Bunz Paul Evans

The bromination of a series of cyclohexenyl substituted secondary amines 1a-i has been investigated using Br2, PHT and NBS. In the case of Br2 and NBS the secondary amines preferentially undergo N-bromination. In contrast, PHT cleanly affords the products of alkene dibromination. In the case ofBr2 the N-bromo species then give the products of alkene dibromination, albeit less efficiently. On su...

2012
Virginia Mazzanti Martina Cacciarini Søren L Broman Christian R Parker Magnus Schau-Magnussen Andrew D Bond Mogens B Nielsen

BACKGROUND The dihydroazulene (DHA)/vinylheptafulvene (VHF) system (with two cyano groups at C1) functions as a photo-/thermoswitch. Direct ionic bromination of DHA has previously furnished a regioselective route to a 7,8-dibromide, which by elimination was converted to a 7-bromo-substituted DHA. This compound has served as a central building block for functionalization of the DHA by palladium-...

2012

The two most common halogenation reactions are chlorination and bromination. The addition of these halogens to alkenes yields 1,2-dihalides. Chlorinations reactions are used to synthesize over 6 million tons per year of ethylene dichloride (1,2-dichloroethane) for use as a solvent and for subsequent polymerization to produce poly(vinylchloride) known more commonly as PVC which is used for plumb...

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