Revisit to the synthesis of 1,2,3,4-tetrasubstituted pyrrole derivatives in lactic acid media as a green solvent and catalyst

In this study, for the first time, lactic acid was used as a bio-based green catalyst and reaction medium for the synthesis of 1,2,3,4-tetrasubstituted pyrrole derivatives from one-pot three-component reaction of commercially available primary amines, 1,3-dicarbonyl compounds, and trans-β-nitrostyrene at room temperature. Thirty-three corresponding pyrroles, of which eight are novel and have been reported for the first time, were synthesized in high to excellent yields in lactic acid media and characterized by spectroscopic analysis. In all examined cases, lactic acid represented many advantages, including shorter reaction time, ease of product isolation, higher yields, no by-products, no chromatographic process, and lower volatility in the reaction. This bio-based green solvent can also be recycled and reused three times without loss of its efficiency as a catalyst and solvent.

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

Microwave-assisted (MWA) multicomponent reactions (MCRs) have successfully emerged as one of the useful tools in the synthesis of biologically relevant heterocycles. These reactions are strategically employed for the generation of a variety of heterocycles along with multiple point diversifications. Over the last few decades classical MCRs such as Ugi, Biginelli, etc. have witnessed enhanced yield and efficiency with microwave assistance. The highlights of MWA-MCRs are high yields, reduced reaction time, selectivity, atom economy and simpler purification techniques, such an approach can accelerate the drug discovery process. The present review focuses on the recent advances in MWA-MCRs and their mechanistic insights over the past decade and shed light on its advantage over the conventional approach.

Ionic Liquid-assisted Preparation of Two-dimensional ZnO/Fe3O4 Nano-composites and their Application in Polysubstituted Pyrroles Synthesis

AIMS AND OBJECTIVE

Ionic liquids are a suitable medium for stabilization and preparation of catalytic systems.

MATERIALS AND METHODS

The two-dimensional (2D) ZnO/Fe3O4 nanocomposites were synthesized using ionic liquid [OMIM]Br as a stabilizer and soft template. The nanocomposites were characterized via FTIR, XRD, VSM and SEM analysis.

RESULT

The catalytic activity of these composites was evaluated using a multicomponent reaction of primary amines, acetylacetone, and 2-bromoacetophenone.

CONCLUSION

2D ZnO/Fe3O4 as a recyclable and green catalyst showed excellent catalytic performance for the preparation of poly-substituted pyrroles.

A facile method for the synthesis of fused perhydropyrano[2,3-b]pyrans promoted by Yb(OTf)3

A stereospecific three-component domino reaction between glycals, alkylidene malonate and aldehydes catalyzed by Yb(OTf)3 is described. Multi-substituted cis-fused perhydropyrano[2,3-b]pyran derivatives were obtained with high diastereoselectivity.

Active methylenes in the synthesis of a pyrrole motif: an imperative structural unit of pharmaceuticals, natural products and optoelectronic materials

Pyrrole is one of the most important azaheterocycles, due to its wide range of applications in pharmaceuticals and optoelectronic materials, coupled with its utility as an intermediate in natural products.

A one-pot sequential five-component domino reaction for the expedient synthesis of polysubstituted pyrroles

A new protocol towards the synthesis of polysubstituted pyrroles via enaminone from one-pot five-component reactions under catalyst free conditions.

Potentially antibreast cancer enamidines via azide–alkyne–amine coupling and their molecular docking studies

Potentially antibreast cancer enamidines were synthesized and evaluated against human breast cancer cell line MCF7 displaying GI₅₀values lower than doxorubicin.

Recent advances in the synthesis of pyrroles by multicomponent reactions

Pyrrole is one of the most important one-ring heterocycles. The ready availability of suitably substituted and functionalized pyrrole derivatives is essential for the progress of many branches of science, including biology and materials science. Access to this key heterocycle by multicomponent routes is particularly attractive in terms of synthetic efficiency, and also from the environmental point of view. We update here our previous review on this topic by describing the progress made in this area in the period between mid-2009 and the end of 2013.

Zirconocene dichloride catalysed one-pot synthesis of pyrroles through nitroalkene-enamine assembly

Zirconocene dichloride was found to be a highly efficient catalyst for the synthesis of multi-substituted pyrroles by a three-component, one-pot reaction.

Deep eutectic solvent based on choline chloride and malonic acid as an efficient and reusable catalytic system for one-pot synthesis of functionalized pyrroles

Deep eutectic solvent (DES) based on choline chloride and malonic acid was applied as catalyst and reaction medium for synthesis of pyrroles by one-pot, four-component reaction of amines, aldehydes, 1,3-dicarbonyl compounds and nitromethane.