Synthesis and structural investigation of some 1,4-disubstituted-2-pyrrolidinones

Kristina Brokaite,Vytautas Mickevicius,Gema Mikulskiene

doi:10.3998/ark.5550190.0007.206

Kristina Brokaite, Vytautas Mickevicius + Show 1 more

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https://doi.org/10.3998/ark.5550190.0007.206

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Abstract

A series of 1,4-disubstituted 2-pyrrolidinones was synthesized by condensation of 1-aryl-4hydrazinecarbonyl-2-pyrrolidinones with aromatic aldehydes, acetone, 2-butanone, and 2,4pentane-dione. Most of the reaction products have isomers owing to the amide and azomethine structural units in their molecules. Computer molecular modeling was used to study individual features of each isomer. The structures of the synthesized compounds were unambiguously elucidated by combining IR, mass, H, and C NMR spectroscopy on the basis of the theoretical characteristics derived from molecular modeling. In this work the NMR spectra of the studied compounds 3–9 revealed a successful choice of the representative examples and good support for the explication of the peculiarities of s-cis and s-trans isomers formed in amides by the existence of E/Zconfigurations in azomethine fragments using solvents of different polarity. Data for the complete NMR assignments are presented.

Highlights

We continued our interest in the chemistry of N-aryl- substituted amino acids and products of their cyclization
Elucidation of the intricate NMR spectra of these compounds was possible only through ascertaining the completeness of effects by considering the data derived from computer molecular modeling computations
The aim of our work was the synthesis of compounds [3,4,5,6,7,8,9,10] and the choice of relevant approaches to the structural analysis of the synthesized products distinguished by their property to form isomers of different orientation and origination

Summary

Introduction

We continued our interest in the chemistry of N-aryl- substituted amino acids and products of their cyclization. The assignments of NMR resonances rested on the chemical shifts,[4,5] signal intensity, multiplicities, and comparison with structurally related compounds. These structural fragments allowed the formation of isomers [6,7,8,9,10,11,12] notably reflected in the NMR spectra.

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