L-butyl-2,3-dimethylimidazolium

In a closely related approach, Yen and Chu have reported the preparation of tetra-hydro-/3-carbolinediketopiperazines employing a three-step Pictet-Spengler, Schot-ten-Baumann, and intramolecular ester amidation sequence (Scheme 6.233) [415]. Throughout the synthesis, the ionic liquid l-butyl-2,3-dimethylimidazolium hexa-fluorophosphate (bdmimPF6) was employed. In a typical experiment, (S)-tryptophan methyl ester was dissolved in a 1 1 mixture of the ionic liquid and tetrahydrofuran... 

As a demonstration of the complete synthesis of a pharmaceutical in an ionic liquid, PravadoHne was selected, as the synthesis combines a Friedel-Crafts reaction and a nucleophilic displacement reaction (Scheme 5.1-24) [53]. The alkylation of 2-methyhndole with l-(N-morpholino)-2-chloroethane occurs readily in [BM1M][PF ] and [BMMlM][PFg] (BMMIM = l-butyl-2,3-dimethylimidazolium), in 95-99 % yields, with potassium hydroxide as the base. The Friedel-Crafts acylation step in [BMlM][PFg] at 150 °C occurs in 95 % yield and requires no catalyst... 

Figure 9.6 Efficiency of extraction of various compounds into imidazolium ILs (optimal conditions). Abbreviations BMIm— l-butyl-3-methylimidazolium, C4CjIm BM2Im—l-butyl-2,3-dimethylimidazolium, C4CjCjIm.

OMIM]+ l-octyl-3-methylimidazolium, [DMIM]+ l-decyl-3-methylimidazolium, [b-diMIM]+ l-butyl-2,3-dimethylimidazolium, [BZMIM]+ l-benzyl-3-methylimidazolium, [OH-EMIM]+ l-hydroxyethyl-3-methylimidazolium, [CHES]- 2-(cyclohexylamino)ethanesulfate... 

A broader exploitation of cellulose solubility in ionic liquids lies in modification of cellulose into more useful forms. Cellulose acetate is currently the most useful derivative of cellulose, with uses in photographic film, as a synthetic fibre and as a component of adhesives. Acetylation of cellulose has been carried out effectively in l-allyl-3-methylimidazolium chloride [Amim][Cl], [C4mim CI], [C2mim][Cl], l-butyl-2,3-dimethylimidazolium chloride [C4dmim][Cl] and l-allyl-2,3-dimethyl-imidazolium bromide [Admim][Br] [136, 159-162], The first report of cellulose acetylation in an ionic liquid involved a one-step reaction in [Amim][Cl] without catalyst, yielding cellulose acetate with a controllable degree of substitution [136], Yields of cellulose acetate of up to 86% have been obtained via reaction in [C4mim] [Cl] at 80 °C for 2 h [160],... 

Andriyko Y, Nauer GE (2007) Electrochemistry of TlCl in l-butyl-2,3-dimethylimidazolium azide. Electrochim Acta 53 957-962... 

Itoh T, Nishimura Y, Ouchi N, Hayase S (2003) l-Butyl-2,3-dimethylimidazolium tetrafluo-roborate the most desirable ionic liquid solvent for recycling use of enzyme in lipase-catalyzed transesterification using vinyl acetate as acyl donor. J Mol Cattil B Enzym 26 41 5... 

Industrially performed catalytic oxidation reactions often suffer from drawbacks such as poor conversion and selectivity due to overoxidation, corrosive reaction media, lack of solvent and catalyst recycling, and negative environmental impact due to evaporation of the solvents. In order to provide a methodology that addresses these problems, ionic liquids have been investigated as reaction media. For example, the aerobic oxidation of benzyl alcohol and alkylbenzene to benzaldehyde and benzoic acids was performed in l-butyl-2,3-dimethylimidazolium tetrafluoroborate ([C4dmim][BF ]) using palladium and cobalt complexes respectively [34, 35]. 

BMIM] = l-butyl-3-methylimidazolium EMIM = 1-ethyl-3-methylimidazo Hum [OMIM] = 1-octyI-3-methylimidazolium BMMIM = l-butyl-2,3-dimethylimidazolium [OMMIM] = 1-octyl-2,3-dimethyIimidazolium (BMPY = 1-butyl-1-methylpyrrolidinium. 

Apart from [EMIM]+ cation, researchers have explored other imidazolium-based cations such as l-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl) imide ([BDMIM]), l-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM]), and l-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C12MIM]) [627,628]. For example, Bettini et al. [628] investigated four ILs including [BMIM][NTf2], [Ci2MIM][NTf2], [EMIM][NTf2], and 1-butyl-l-methylpyrrolidinium... 

Electrochemical reduction of Ti(IV) species has been studied in two trisubstituted imidazolium ILs [8-10], both based on the l-butyl-2,3-dimethylimidazolium cation with Bp4 (BMMImBFq) and azide (BMMImN3) anions (Fig. 6.1). The solutions of TiCl4 in both salts and Tip4 in BMMIniBF4 were investigated. 

H.C., and Trulove, P.C. (2005) TGA decomposition kinetics of l-butyl-2,3-dimethylimidazolium tetrafluoroborate and the thermal effects of contaminants. J. Chem. Thermodyn., 37, 900 905. 

---