One-pot Synthesis of 2,4,5-trisubstituted Imidazoles Catalyzed by Lipase

Silica supported lanthanum trifluoroacetate and trichloroacetate as an efficient and reusable water compatible Lewis acid catalyst for synthesis of 2,4,5-triarylimidazoles via a solvent-free green approach

In the present research article, we have developed solid heterogenous silica supported lanthanum trifluoroacetate and trichloroacetate as green Lewis acid catalysts. These catalysts were synthesized by a novel, simple, cheap, clean, and environment friendly method. The physicochemical properties of the prepared catalysts were well studied and characterized by sophisticated spectroscopic techniques such as FTIR, TGA, XRD, EDX, SEM, TEM and BET analysis. The catalyst was utilized in the synthesis of arylimidazole derivatives via green protocols under solvent-free conditions at 70 °C with a higher yield, mild reaction conditions and a short reaction time. The catalyst works superiorly in water as well as in various organic solvents as a reusable and easily recoverable catalyst.

A sustainable approach towards the three-component synthesis of unsubstituted 1H-imidazoles in the water at ambient conditions

A green protocol for the synthesis of unsubstituted imidazoles has been demonstrated herein. The reaction is realized using commercially available lipase enzyme, porcine pancreas lipase (PPL) in water. The reaction conditions are selective and mild which helped to tolerate a wide variety of functional groups to give the desired products in good chemical yields.[Formula: see text].

Emerging Trends in the Syntheses of Heterocycles Using Graphene-based Carbocatalysts: An Update

Graphene-based carbocatalysts owing to numerous amazing properties such as large specific surface area, high intrinsic mobility, excellent thermal and electrical conductivities, chemical stability, ease of functionalization, simple method of preparation, effortless recovery and recyclability have gained a superior position amongst the conventional homogeneous and heterogeneous catalysts. In this review, an endeavor has been made to highlight the syntheses of diverse heterocyclic compounds catalyzed by graphene-based catalysts. Further, the study also reveals that all the catalysts could be reused several times without significant loss in their catalytic activity. Additionally, most of the reactions catalyzed by graphene-based carbocatalysts were carried out at ambient temperature and under solvent-free conditions. Thus, the graphene-based catalysts do not merely act as efficient catalysts but also serve as sustainable, green catalysts. This review is divided into various sub-sections, each of which comprehensively describes the preparation of a particular heterocyclic scaffold catalyzed by graphene-derived carbocatalyst in addition to synthesis of graphene oxide and reduced graphene oxide, functionalization, and structural features governing their catalytic properties. Synthesis of heterocycles catalyzed by graphene-based carbocatalysts.

Direct synthesis of 2,4,5-trisubstituted imidazoles from primary alcohols by diruthenium(ii) catalysts under aerobic conditions

A straightforward synthetic approach to 2,4,5-trisubstituted imidazoles from readily available primary alcohols using arene diruthenium(ii) catalysts has been described.

The first protection-free synthesis of magnetic bifunctional l-proline as a highly active and versatile artificial enzyme: Synthesis of imidazole derivatives

l-Proline is a bifunctional versatile organocatalyst that could promote a variety of useful transformations. Some passive and dynamic interactions between this simple amino acid and different substrates, which are necessary to enzymatic reactions, have given it "the simplest enzyme" title. Herein we presented the first report on the synthesis of magnetic bifunctional l-proline as an artificial enzyme without requiring any protection/deprotection steps according to an operationally simple process. This magnetic nano-biocatalyst is a promising catalyst that in a case study was successfully applied for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles in the 70-99% and 60-90% yields respectively, which it could be extended to the variety of l-proline-based organic transformations. The synergic effect of bifunctional l-proline shell as catalytic active site and magnetite nanoparticles core, which could function as protein mimics endow it high efficiency, versatility, recoverability, reusability and good turnover frequency, which are necessary characters for artificial enzymes' designing.

Current advances in the synthesis and biological potencies of tri- and tetra-substituted 1H-imidazoles

In this report, we review the current chemistry progress and in particular the synthesis approaches of tri- and tetra-substituted imidazoles.

Graphene oxide–chitosan bionanocomposite: a highly efficient nanocatalyst for the one-pot three-component synthesis of trisubstituted imidazoles under solvent-free conditions

An eco-friendly and clean GO–biopolymer heterogeneous nanocatalyst was prepared and characterized, which efficiently promoted an important organic reaction.

Iron nanotube-silica composite (ZVI-S-PCAT modified silica composite) preparation, characterization and application as a recyclable catalytic system for 5-membered ring organic transformations

The ZVI-S-PCAT modified silica composite is a successful catalytic framework for synthesizing 5-membered heterocylic rings and a future sensor material.

One-pot chemoenzymatic multicomponent synthesis of thiazole derivatives

A novel chemoenzymatic one-pot multicomponent synthesis of thiazole derivatives was developed. A series of thiazole derivatives were synthesized with high yields up to 94% under mild enzyme-catalyzed conditions. The blank and control experiments reveal that trypsin from porcine pancreas (PPT) displayed great catalytic activity to promote this reaction and showed a wide tolerance range towards different substrate amines. This trypsin-catalyzed multicomponent conversion method provides a novel strategy to synthesize thiazole derivatives and expands the application of enzymes in organic synthesis.