Deep Eutectic Solvents as Unconventional Media for Multicomponent Reactions

Abstract

Regarding all the green aspects of sustainable chemical transformations, eco-friendly processes along with economic development, environmental protection as well as natural resources preservation are mandatory. The use of unconventional media for organic transformations has been part of the quest for new eco-friendly process. As new alternative media for volatile organic solvents, deep eutectic solvents (DES) can be defined as the eutectic mixtures formed of two or more phase-immiscible components, which furnish a new homogeneous liquid phase with lower freezing point than those observed for individual counterparts. They found applications in several different fields, such as solvent/catalyst for organic transformations, biotransformations, and polymerization reactions, metal and biomass processing applications, and separation technologies. This review describes the recent studies on the use of deep eutectic mixtures as solvent and/or catalyst for multicomponent reactions in the synthesis of complex organic compounds.

A methanol and protic ionic liquid Ugi multicomponent reaction path to cytotoxic α-phenylacetamido amides

“…Given the clear enhanced cytotoxicity of analogues containing the acetylenic moiety, and the similarity to those from the Yamada report, 30 we sought to directly compare both analogues sets and expand the pharmacophore of these compounds. Thus, we in-house synthesised lead 1 and three additional methoxy analogues (19)(20)(21) as per Scheme 2. Screening data for these four analogues (1,(19)(20)(21) is presented in Table 5.…”

“…Thus, we in-house synthesised lead 1 and three additional methoxy analogues (19)(20)(21) as per Scheme 2. Screening data for these four analogues (1,(19)(20)(21) is presented in Table 5. Analysis of these data is consistent with the acetylene moiety analogues being sub-micromolar cytotoxic with all four analogues returning average GI 50 values # 1 mM for the cancer cell lines examined.…”

“…[8][9][10] Multicomponent reactions (MCRs) are key 'medicinal toolkit' reactions permitting rapid assembly of three or more components in a one-pot sequence to produce a nal product. [11][12][13][14][15][16][17][18][19][20] MCRs present the medicinal chemist with additional benets beyond rapid compound access and diversity, they are typically highly atom economic producing less waste and require fewer resources, less time, energy and human effort. In many cases simpler purication processes and high convergence are also evident.…”

Systematic evaluation of hydrophobic deep-melting eutectics as alternative solvents for the extraction of organic solutes from aqueous solution

“…24,25 Finally, while the practical utility of ionic liquids is sometimes limited by their expense (uorinated anions being particularly problematic in this context), 26,27 numerous DESs can be prepared from inexpensive, commodity chemicals. 28 These favorable characteristics have led to a range of applications in a variety of elds, including synthesis, 29,30 catalysis, 31 and chemical analysis, 32 among others. While the vast majority of deep eutectic solvents described to date are hydrophilic, 33,34 recent work has shown that a hydrophobic DES (designated hereaer as an HDES) can be readily obtained by combining menthol [35][36][37][38] or an appropriate quaternary ammonium halide [39][40][41] with a longchain carboxylic acid.…”

Polymer synthesis in non-ionic deep eutectic solvents

“…1 Over the past decades, the unique properties of deep eutectic solvents (DESs) have been exploited in areas as diverse as the synthesis of fine chemicals and materials and in drug delivery. [2][3][4][5][6][7][8][9][10][11][12][13][14] They are traditionally comprised of two or more components, where at least one is ionic, accordingly. Soviet scientists aiming to develop liquid fertilizers discovered the first non-ionic deep eutectic liquid, a mixture of acetamide (67 wt%) and urea (33 wt%), with melting points of 80°C and 133°C, respectively, and a eutectic temperature of 56°C.…”