Heterocyclic ionic liquids, reviews

Thus, most ionic liquids are formed from cations that do not contain acidic protons. A summary of the applications and properties of ionic liquids may be found in a number of recent review articles [3]. The most common classes of cations are illustrated in Figure 2.1-1, although low melting point salts based on other cations, such as complex poly cationic amines [4] and heterocycle-containing drugs [5], have also been prepared. 

Lina Mehta obtained B.Sc., M.Sc., and Ph.D. degrees in India before moving to the Chemistry Department at Brunei University in 1989 as a postdoctoral research fellow. Her work has been centered mainly in synthetic organic chemistry associated with anticancer research in collaboration with Cancer Research UK, Gray Cancer Research Trust, and Royal Marsden Hospital in the UK, and with several other research institutes in the USA and Australia. The Chemistry Department at Brunei finally closed in 2000 and Dr. Mehta moved into the Centre for the Environment and subsequently into the Institute for the Environment at Brunei. Her main area of research at present is on the synthesis and application of ionic liquids to environmental problems. She has published numerous research papers in various journals and co-authored reviews on aspects of heterocyclic chemistry for several well-known series of books. 

Numerous applications have been found for the uses of imidazole derivatives as ionic liquids and A -heterocyclic carbenes and their use in organic chemistry has been well discussed in books or reviews. Thus, in this chapter, the use of non-heteroaromatic amidine compounds as functional tools in asymmetric synthesis and the related chemistry after presentation of the preparation method of amidines will mainly be discussed. 

In this review, the use of N-heterocyclic carbene complexes derived from imidazoHum salts as a part of the different strategies involving ionic liquids has not been considered. Nevertheless, it can be important to take into account this reactivity, especially when 1,3-dialkylimidazolium ILs are involved. For more details about this aspect and applications in hydroformylation, one can refer to Herrmanrfs recent review [55] and the later publication of Poyatos et al. in 2003 [56]. 

Some recent reviews of ionic liquids (a) Ohno, H. Functional design of ionic liquids. Bull. Chem. Soc. Jpn. 2006, 79,1665-1680. (b) Martins, M. A. R Frizzo, C. R Moreira, D. N. Zanatta, N. Bonacorso, H. G. Ionic hquids in heterocyclic synthesis. Chem. Rev. 2008,108, 2015-2050. (c) Hapiot, R Lagrost, C. Electrochemical reactivity in room-temperature ionic liquids. Chem. Rev. 2008, 108, 2238-2264. (d) Giernoth, R. Task-specific ionic liquids. Angew. Chem. Int. Ed. 2010, 49, 2834—2839. 

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