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A series of novel lipid-inspired ionic liquids have been synthesized employing the thiol-ene "click" reaction in a single-step process. The thermal properties were determined by differential scanning calorimetry (DSC) and showed observable trends between the C16, C18, and C20 analogues. The minimum melting points for each equivalent chain length series occur at sequential odd sulfur positions, 3, 5, and 7 for the C16, C18, and C20 series, respectively. The magnitude of melting point depression relative to the saturated homologue is observed to have a strong dependence on the position of the sulfur in the side chain. Additionally, the sulfur position corresponding to the lowest melting point for a homologous series shifts further down the chain as the chain length is increased, indicating that the maximum effect takes place near the center of the ion and not the center of the thiaalkyl chain. This synthesis provides tunability and improved thermal stability for 1-methyl-3-thiaalkylimidazolium bistriflimides and insight into structure-property relationships of lipidic ionic liquids.

We present an efficient Ullmann-type synthesis methodology enabling the preparation of imidazolium compounds with an extended aromatic core in three steps. This procedure begins with a microwave-assisted, heterogeneously catalysed cross-coupling reaction in the presence of Cu(ii)-doped NaY zeolite to obtain imidazole-aromatic derivatives directly in good yield. The innovation is that this reaction does not require solvent, ligand or an inert atmosphere. Subsequently, these derivatives have been alkylated with bromoalkanes and the bromide of the imidazolium products exchanged for [BF4]− or [PF6]− anions. We have studied the influence of the methyl group (inductive effect) on the aromatic unit during the coupling reaction as well as its impact on different arrangements in the crystalline state. We have been able to extend this synthesis to ionic liquid crystal compounds which display lamellar self-organization (smectic A). The mesomorphic behavior and phase transition temperatures were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS). [ABSTRACT FROM AUTHOR]

The synthesis of a series of new lipid-inspired ionic liquids through thiol-ene 'click' reaction with a single-step process. This synthesis offers considerable promise as an efficient and orthogonal method to construct structurally diverse imidazolium-type ionic liquids with linear and branched cationic tails, as well as versatility in the placement of the sulfur heteroatom. Profound solvent effect in this ene reaction regioselectivity has been observed. [ABSTRACT FROM AUTHOR]

This article reports a fast, simple and efficient method to synthesize highly substituted imidazoles. Green organic synthesis is needed to face current environmental pollution. For instance the replacement of hazardous organic compounds by safe alternatives is particularly relevant. Ionic liquids are an environmentally friendly alternative to conventional organic solvents due to their unique physicochemical properties. Substituted imidazoles have been widely used to prepare pharmaceuticals. Many synthetic approaches have been developed to produce substituted imidazoles. However, despite considerable efforts only a few green methods are reported for the synthesis of highly substituted imidazoles. Here a straightforward and atom-economic approach is reported to synthesize a series 2,4,5-trisubstituted imidazoles directly from α-hydroxyketones and alcohols employing 1-methyl-3- H-imidazolium nitrate as a promoter and medium under microwave irradiation. The protocol has several advantages such as high yields of 77-91 %, short reaction times of 6-8 min, easy purification processes, and methodological simplicity due to the formation of carbon-carbon and carbon-heteroatom bonds in a single step. The methodology has been further extended towards the facile synthesis of Trifenagrel in good yield. This method provides new opportunities for the rapid screening of a wide range of compounds, either for the development of new drugs or total synthesis of natural products. [ABSTRACT FROM AUTHOR]

Abstract: A wide variety of oximes were prepared from different types of alcohols with hydroxylamine hydrochloride using 1-methylimidaziloum nitrate, [Hmim][NO3], ionic liquid as a reaction medium and promoter under microwave irradiation. This protocol provides a one-pot oxime synthesis with high yields that is facile, eco-friendly and the ionic liquid can be recovered and reused. [Copyright &y& Elsevier]

Abstract: Cyclopropyl moieties embedded in the long aliphatic side chains of imidazolium-type ionic liquids are shown to be highly effective in lowering the T m of such materials relative to counterparts bearing linear, saturated side chains. While not as efficient as olefins in bringing about this effect, ILs incorporating side-chain cyclopropanated modules are likely to be more resistant to aerobic degradation than those employing the former. [Copyright &y& Elsevier]

Thethermophysical properties of three lipidic ionic liquids, 1-oleyl-3-methylimidazoliumbistriflimide, 1-elaidyl-3-methylimidazolium bistriflimide, and 1-linoleyl-3-methyl-imidazoliumbistriflimide are measured at 1 bar as a function of temperature overthe range of 273 K to 353 K and correlated to appropriate models.Each of these compounds is a variation on 1-C18-3-methylimidazoliumbistriflimide, where the C18chain contains one or moreunsaturations, incorporated into the structure to lower the meltingpoint. Derived properties such as molar volume and volume expansivityare also calculated. The data are compared with literature valuesfor shorter chain 1-n-alkyl-3-methylimidazolium bistriflimidesalts. The longer chains impart lower densities and higher viscositiesrelative to their shorter chain homologues. Although the subtle structuraldifferences between the three compounds result in significant differencesin melting points, there is less of an effect on the liquid phasethermophysical properties. [ABSTRACT FROM AUTHOR]

We describe the proficient synthesis and thermotropic mesomorphicity of thioether–functionalized imidazolium–type ionic liquids containing C 12 and C 18 chains associated with Br − and OTf − anions. The mesomorphic behavior and phase transition temperatures were studied by Polarizing Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and Small-Angle X-ray Scattering (SAXS). The ionic liquids with bromide anion display Smectic A lamellar phase giving homeotropic and fan-shaped textures. The layered crystallographic structure is reported by Single-Crystal XRD. The electrochemical characteristics of the ionic liquids with C 18 side chain have been determined via Cyclic Voltammetry. [ABSTRACT FROM AUTHOR]