Search

The di-N-heterocyclic carbene (NHC) dipalladium complexes, [(PdPyBr2)2(di-NHCimi)] and [(PdPyBr2)2(di-NHCtri)], di-NHCimi and di-NHCtrirepresent an imidazolylidene and a triazolylidene, respectively, featuring a 1,4-xylylene spacer between the carbene units, have been prepared. The influences of the imidazolylidene and triazolidene backbone and different substituents on the catalytic activity have been investigated in the Mizoroki-Heck reaction of styrene with bromobenzene. [ABSTRACT FROM AUTHOR]

A series of N-aryl or N-methyl substituted bisimidazolium dichloride or dibromide salts with different alkyl bridge lengths (n = 1–4) have been synthesized starting from N-arylimidazoles or N-methylimidazoles with dialkyl bromides or the less expensive but less reactive dialkyl chlorides under solvent-free conditions. This green protocol provided most bisimidazolium chloride and bromide salts in good yields, and the reaction time was shortened to a few hours. In two examples, we showed either bisimidazolium dichloride (1a) or dibromide salt (3c) can be easily converted to the corresponding dihexafluorophosphate salt (1a′ or 3c′) in near quantitative yield. [ABSTRACT FROM PUBLISHER]

An efficient C-N coupling reaction of aryl chlorides or bromides with imidazole was successfully performed with cheap and commercially available catalytic system Cu(I)/HMTA. Both aryl bromides and aryl chlorides have been effectively catalyzed by Cu/HMTA, giving products in moderate to good yields. Moreover, aryl halides bearing either electron-withdrawing groups or electron-donating groups could be used in the reaction. [image omitted] [ABSTRACT FROM AUTHOR]

A series of novel chiral bisimidazolium and chiral bis(benzimidazolium) dichlorides with different substituents were synthesised effectively from the corresponding N-substituted imidazoles or N-substituted benzimidazoles with chiral (S)-2,2'-bis(2-chloroethoxy)-1,1' -binaphthalene in solvent-free conditions at ambient pressure. This protocol features a short reaction time, good yields, an eco-friendly process and easily control and handling. These compounds were fully characterised by NMR, IR and elemental analysis, and their specific rotations were given. [ABSTRACT FROM AUTHOR]

A series of N,N′-diaryl bisimidazolium dichlorides with different alkyl bridged length (n = 2-6, 10) was synthesised from N-arylimidazoles with the less expensive, but less reactive dialkyl chlorides effectively in solvent-free conditions at ambient pressure. Compared with conventional methods, this protocol features a short reaction time, good yields and an eco-friendly process. [ABSTRACT FROM AUTHOR]