Bmim]Br Accelerated One-Pot Three-Component Cascade Protocol for the Construction of Spirooxindole-Pyrrolidine Heterocyclic Hybrids.

Raju Suresh Kumar,Necmi Dege,Natarajan Arumugam,Dhaifallah M Al-Thamili,Abdulrahman I Almansour

doi:10.3390/molecules25204779

Raju Suresh Kumar, Necmi Dege + Show 3 more

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https://doi.org/10.3390/molecules25204779

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Abstract

Our synthetic approach for the assembly of structurally complex spirooxindole heterocyclic hybrids was based on an ionic liquid, [bmim]Br mediated one-pot three-component cascade reaction strategy involving 1,3-dipolar cycloaddition reaction of N-1-(2-pyridinylmethyl)-3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones and azomethine ylide generated in situ from isatin and L-phenyl alanine, affording a series of spirooxindole–pyrrolidine heterocyclic hybrids in good-to-excellent yields. In addition to serving as the reaction medium, [bmim]Br also functioned as a catalyst in this cycloaddition reaction and hence accelerated the reaction rate affording the cycloadducts in short reaction time.

Highlights

A swift construction of molecular complexity from available and simple starting precursors advances the field of chemistry
The methodology for the synthesis of spirooxindole heterocyclic hybrids is based on a one-pot three-component cascade reaction strategy employing N-1-(2-pyridinylmethyl)-3,5-bis[(E)arylmethylidene]tetrahydro-4(1H)-pyridinones 5a–h, isatin 6, and L-proline 7 involving a key
When all the starting substrates had been consumed completely, as obvious from thin-layer chromatography (TLC) analysis, the reaction mixture was poured into ice cold water

Summary

Introduction

A swift construction of molecular complexity from available and simple starting precursors advances the field of chemistry. One-pot multicomponent cascade reactions are highly effective and prevailing protocols that incorporate multiple bond-forming events, constituting an attractive division of organic chemistry and attaining great interest, as these reactions permit the construction of molecules with noteworthy structural complexity from simple and available starting materials [1–4]. These one-pot cascade reactions have advantages such as atom economy, operational simplicity, and high reaction efficiency, in addition affording better overall yields when compared with the classical single-step transformations [5]. 1,3-dipolar cycloaddition is a powerful synthetic approach for the formation of a variety of heterocycles; this eco-compatible synthetic procedure has recently received a great deal of attention and considerable progress has been achieved in this area [7–9]. 1,3-dipolar cycloaddition reaction of azomethine ylides with activated electron deficient alkenes offers a proficient methodology for synthesizing pyrrolidine heterocyclic hybrids in a regio- and stereoselective fashion [10–12].

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