Novel ionic liquid supported-multicomponent reaction toward chimeric bis-heterocycles

Abstract

A novel multicomponent reaction between IL-anchored 2-aminobenzoimidazoles, aldehydes, and electron-deficient dienophiles has been explored. The strategy was utilized to develop a rapid parallel synthesis for novel bis-heterocyclic skeleton of benzimidazole-linked dihydropyrimidine on an ionic liquid support. This multicomponent reaction is compatible with a wide range of substrates and furnishes the new chimeric scaffolds with high purity and excellent yields. Use of the ionic liquid as a soluble support facilitates purification by simple precipitation along with advantages like high loading capacity, homogeneous reaction conditions, and monitoring of the reaction progress by conventional NMR spectroscopy.

Heterocycles-Based Ionic Liquid-Supported Synthesis of Small Organic Molecules

“…The multicomponent reaction between IL-grafted 2-aminobenzimidazoles, aldehyde, and electron-deficient acetylenes for the synthesis of dihydropyrimidobenzimidazole 116 is also presented in Scheme 12 [48]. The key intermediate, 2-aminobenzimidazoles 115 were constructed by using cyanogen bromide through cyclization of ortho-phenylenediamine 97.…”

“Green” Pericyclic Reactions Assisted by Ionic Liquids

“…The novel multicomponent reaction between IL-anchored, 2-aminobenzoimidazoles, aldehydes, and electron-deficient dienophiles, described below, involve a [1,5]-sigmatropic rearrangement, which was compatible with a wide range of substrates to furnish the new scaffolds. The use of the IL as a soluble support facilitates purification by simple precipitation along with advantages such as high loading capacity, homogeneous reaction conditions and monitoring of the reaction progress by conventional NMR spectroscopy [55]. In another example of [2,3]-sigmatropic rearrangement, an efficient enantioselective approach towards the construction of quaternary indolizidines from proline building block co-catalyzed by the IL 1-butyl-3-methylimidazolium hexafluorophosphate was shown.…”

Synthesis of 1,5-disubstituted-1<em>H</em>-tetrazole methane-linked <em>bis</em>-heterocycles via Ugi-azide

“…16 In this context, the integration of two heterocyclic moieties in a single molecule usually creates unexpected interactions with biological targets enabling discovery of new kind of potent modulators with therapeutic activities enhanced. 17 There are many reports in the literature describing the synthesis of new 1,5-DS-T, which are linked to other heterocycles, 18 but only a few reports of them are via one pot Ugi-azide process, which obtained 1,5-DS-T linked with other heterocyclic. 19 It is noteworthy that only two reports described for the synthesis of 1,5-DS-T linked with furans.…”