1.3- diethyl-5-methylimidazolium

The Diels-Alder reaction is an important and widely used reaction in organic synthesis (Sauer and Sustmann, 1980), and in the chemical industry (Griffiths and Previdoli, 1993). Rate enhancement of this reaction has been achieved by the use of solvents such as water, surfactants, very high pressure, lithium amides, alkylammonium nitrate salts, and macrocyclic hosts (Sherman et ak, 1998). Diels-Alder reactions can be ran in neutral ionic liquids (such as 1-butyl-3-methylimidazolium trifluoromethanesulfo-nate, l-butyl-3-methylimidazolium hexafluorophophate, l-butyl-3-methylimidazolium tetrafluoroborate, and l-butyl-3-methylimidazolium lactate). Rate enhancements and selectivities are similar to those of reactions performed in lithium perchlorate-diethyl ether mixtures. 

A similar principle is applied in dispersion polymerization in ionic liquids produced particles are in sub-micron range (41,42). The monomer, initiator and colloidal stabilizer are soluble in the liquid medium, but the obtained polymer is not. Different kinds of ionic liquids may be used, such as for styrene l-butyl-3-methylimidazolium tetrafluoroborate or N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide. In general, radical polymerization in ionic liquids provides higher polymerization rate and higher molecular weights than the process in bulk or organic solvents (homogenous system). 

Naphthol (0.35 mmol) was dissolved in 2 ml l-ethyl-3-methylimidazolium tetrafluoroborate containing benzyl bromide (1.5 eq) and KOH (2eq). The mixture was reacted in a microwave apparatus at 200°C 2 minutes, the product extracted with diethyl ether, and isolated in quantitative yield. 

The fluorescent probe 4-aminophthalimide (63) as well as its /V,/V-diethyl homomorph (89) were used by Samanta and coworkers148 149 to study the polarity and fluorescence dynamics in l-alkyl-3-methylimidazolium salts. The alkyl groups were variously ethyl, butyl and octyl and the anions were nitrate, tetrafluoroborate, hexafluorophosphate and bis(triflyl)imide. Similar conclusions were reached concerning the effects of alkyl chain length and anion as those obtained by Carmichael and Seddon142 using Nile Red. The solvation dynamics were found to depend on the viscosity of the media. Further use of 63 in l-butyl-3-methylimidazolium hexafluorophosphate was reported by Ingram and... 

As part of their study on gastric (H+/K+)-ATPase inhibitors, Kang et al. developed a simple and convenient synthetic approach to 1,2,3-trisubstituted pyrrolo[3,2-c]quinolines by means of Pd-catalyzed heteroannulation of 4-amino-3-iodoquinoline derivatives with internal alkynes [76]. The following scheme shows an example of a reaction using 4-arylamino-3-iodoquinoline derivative 180 with alkyne 181 to provide 1-arylpyrrolo [3,2-c]quinoline 182, illustrating the possibility of introducing diverse substituents to 1-arylpyrrolo[3,2-c]quinolines. In addition, a Pd-catalyzed domino hydroarylation/ cyclization process was reported to form substituted quinolines [77]. Thus, 3-arylquino-lines were prepared in 56-74% yield when 3,3-diethyl-l-phenyl-1-propyne and aryl iodide were refluxed in ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate [(bmim)BF4 ],in the presence of HCO2H, EtjN, and palladium catalyst. Meanwhile,... 

Polycondensation of diethyl 1,8-octanoic diacid and 1,4-butanediol at room temperature and at 60°C was carried out in l-butyl-3-methylimidazolium hex-afhrorophosphate ionic liquid (see also Chapter 13 for enzymatic polymerizations in unconventional solvents), using lipase PS-C as catalyst [42]. The highest molecular weight polymer (M = 4300 M , = 5400) was obtained at 60 °C for 7 days. 

In 2002, Ansari and Gree developed a simple and mild TEMPO-CuCl catalyzed aerobic oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones in l-butyl-3-methylimidazolium hexafluor-ophosphate [bmim][PF6] (Fig. 28) 99). Thus, a mixture of alcohol (Immol) and TEMPO (0.05 mmol) was reacted with latm O2 at 65°C in the ionic liquid. The products were simply isolated by extraction with diethyl ether. We note, however, that it is a pity that a more environmentally acceptable solvent was not used for product extraction. 

The ionic liquids, [BMIMjBr, [BMIM][BF4], [BMIMjlPFe], [BDMIM][BF4], and [BPY][BF4], were examined as the solvent media for dialkylzinc addition to aldehydes giving the corresponding alcohols. The ionic liquid [BPY][BF4] was found to be the solvent of choice, giving the best yields, and was found to be easily recovered and reused [226] (Scheme 5.2-95). It was found that the imidazoUum salts react with diethyl zinc to form a carbene complex of zinc, but the 2-methylimidazolium or pyridinium salts did not react and hence could be recycled. 

The aldol reactions were also p>erformed in ionic liquid solvents namely N,N-diethyl-N -hexyl-N -methyl-N",N"dipropylguanidinimn iodide and the commercially available 1-butyl-3-methylimidazolium tetrafluoroborate [bmimJpFJ (Shah, Khan et al. 2009). Equimolar ratios of cyclohexanone and 4-bromobenzaldehyde were used and the reaction mixture was extracted with diethyl ether. The guanidinium salt gave improved results than the neat reaction. Application of the commercially available [bmimjpFJ resulted in a rapidly diminishing enantioselectivity for the recycling. 

In this chapter, NMR studies for four ILs having a common anion bis(fluoromethylsulfonyl)amine (TFSA) will be described. The cations are N-ethyl-N-methylimidazolium (EMIm), N,2-dimethyl-N-propylimidazolium (DMPIm), N-methyl-N-propylpyrrolidinium (F 13), and N,N-diethyl-N-methyl-N-(2-methoxylethyl)ammonium (DEME). These ILs are important candidates to use as electrolytes in various batteries or cells. The basic properties of molecular weight (MW), viscosity (q) and cation and TFSA diffusion coefficients (Dcaiion and ZTtfsa) measured at 30°C are given in Table 1 for the four ILs. The experimental data have been published in our previous papers for individual ILs.i-4 In the present chapter, the individual experimental data for the four ILs are plotted on a sheet to clarify the cation properties. In addition, newly derived plots of Dcaaon versus correlation times of molecular motion are included. The chemical structures of the ions are shown. 

The use of metallorganic precursors also allows for a clean route to metal oxide nanoparticles. By employing diethyl zinc as a starting material, Williams and coworkers have shown that ZnO epoxy-resin nanocomposites and ZnO-coated carbon nanotubes may be prepared. The benefit of this method is the lack of undesirable by-products here, only ethane is produced. Given the pyrophoric nature of diethyl zinc, this reaction should be carried out under inert conditions. Ionic liquids too have been used in the low temperature synthesis of ZnO nanoparticles. Li et al. have employed 1-butyl-3-methylimidazolium chloride, in conjunction with zinc acetate and sodium hydroxide, to prepare hexagonal wurtzite ZnO nanoparticles which were formed upon simple grinding at room temperature for under an hour. ... 

C10H21N2O4P + l-Efliyl-3-methylimidazolium diethyl phosphate EVLM 1311 LB5322... 

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