3- imidazolium bromide

A variety of silver(I) carbenes can be prepared by interaction of a series of imidazolium salts with silver(I) oxide or silver(I) carbonate (OOJCS(D) 4499). With 3-tert-butyl-l-(2 -pyridylmethyl)imidazolium bromide hydrate and 3-(2", 6"-di-Ao-propylphenyl)-l-(2 -pyridylmethyl)imidazolium bromide hydrate, complexes 85 (R = t-Bu, 2",6"-/-Pr2CgH3) result. 3-(2",4",6"-Trimethylphenyl)-l-(2 -pyridylmethyl)imidazolium bromide in turn leads to 86 (R= 2",4",6"-MejCgH2). 3-(2",6"-Di-wo-propylphenyl)-l-(2 -pyridyl)... 

Preparation of N-alkoxyalkylimidazolium salts and ionic liquids or gels containing them 1 -Methyl- 3-methoxyethyl imidazolium bromide Foundation for Scientific Technology Promotion, Japan 2002 21... 

No examples of such reactions have been disclosed. Displacement of halogens on the parent heterocycle through metal-catalyzed processes have surprisingly not been reported to our knowledge on the neutral heterocycle. Recently, Suzuki-Miyaura cross-coupling reactions of imidazolium bromide 113 with various boronic acids or esters were reported <2005T6207> to proceed in good yield, without deprotonation at the C-3 position (Scheme 35). 

Application may be found for ionic liquids of resonance-stabilized methanides which can easily be prepared from the alkali salts. The first synthetic step includes the formation of the nearly insoluble silver salts in water (AgX, X = methanide). Since the silver salts dissolve in 2N aqueous NH3, adding ethyl(methyl)imidazolium bromide (EMHBr") results in the formation of a water-soluble ethyl(methyl)imidazolium methanide (EMHX") which can be separated from the AgBr precipitate by filtration. ... 

Shen and co-workers reported a method for preparing lanthanide-NHC halides through protonolysis.75 Reaction of the imidazolium bromide salt with anionic LiLn(N Pr)4 affords salicylaldiminato-functionalized NHC-lanthanide bromides (Scheme 33). The complexes were all characterised by single crystal X-ray diffraction and exhibit capped octahedral geometries. The NHC-Ln MIC bond angles decrease Nd>Sm>Er> which is consistent with decreasing ionic radii, and the Ln-NHC bond lengths also... 

A 20 mM solution of the Step 3 product in acetonitrile and A-methyl-A -methoxy-methyl-imidazolium bromide was prepared. The mixture was heated and left to stand at ambient temperature for 30 minutes. An organogel and ionogel formed that were observed using a dark-field optical microscope. The organogel indicated the presence of microcrystals suggesting that they have an associated fibrous structure or that crystals were formed by the slide cover glass the micron-level fibrous structures were not observed in the ionogel. 

Recently, the reactivity of N-heterocyclic carbenes with bromine and some chloride sources were reported. Imidazolium chloride salts are sometimes obtained as side products when carbene (1) is reacted with main group species to produce main group carbene adducts. However, they can be prepared directly from the reaction of carbene (1) (R = Mes, R = H) with chloroalkanes, such as hexachloroethane in acetonitrile (134). Reaction of carbene (1) (R = Mes, R = H) with Br2 or 1,2-dibromoethane affords the 2-bromo-l,3-bis(2,4,6-trimethylphenyl) imidazolium bromide (135). 

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