Stereochemical Investigations of DiastereomericN-[2-(Aryl)-5-methyl-4-oxo-1,3-thiazolidine-3-yl]-pyridine-3-carboxamides by Nuclear Magnetic Resonance Spectroscopy (1D and 2D)

Öznur Demir-Ordu,Sumru Ozkirimli,Hale Demir-Dündar

doi:10.1155/2015/609250

Abstract

Some newN-[2-(aryl)-5-methyl-4-oxo-1,3-thiazolidine-3-yl]-pyridine-3-carboxamides were synthesized and their structures were investigated by IR, NMR (1H,13C, and 2D), and mass spectra. The presence of C-2 and C-5 stereogenic centers on the thiazolidinone ring resulted in diastereoisomeric pairs. The configurations of two stereogenic centers were assigned based upon1H NMR analysis of coupling constants and 2D nuclear overhauser enhancement spectroscopy (NOESY) experiment. Resolution of the diastereoisomers was performed by high performance liquid chromatography (HPLC) using a chiral stationary phase.

Highlights

Pyridine-3-carboxamide, known as vitamin PP, is part of the vitamin B group and plays an important role in biological oxidative chemistry
Several studies have been done on these compounds regarding enantiodifferentiation of stereoisomers in the presence of chiral auxiliary [28], separation of enantiomers by chiral high performance liquid chromatography (HPLC) [29, 30], and determination of absolute conformations [31, 32]
It is well known that combinations of two or more heterocyclic scaffolds in one molecule can provide a series of compounds with a broad spectrum of biological activity

Summary

Introduction

Pyridine-3-carboxamide (nicotinamide), known as vitamin PP (pellagra protective), is part of the vitamin B group and plays an important role in biological oxidative chemistry. Stereochemical factors generally have important influence on biological activity of the drug molecules. Several studies have been done on these compounds regarding enantiodifferentiation of stereoisomers in the presence of chiral auxiliary [28], separation of enantiomers by chiral HPLC [29, 30], and determination of absolute conformations [31, 32]. It is well known that combinations of two or more heterocyclic scaffolds in one molecule can provide a series of compounds with a broad spectrum of biological activity. We combine thiazolidin-4-one and pyridine-3-carboxamide scaffolds together as part of an ongoing project directed towards the design and synthesis of biologically active nitrogen and sulfur containing heterocyclic compounds [33]. The analytical chromatographic separation of some derivatives by chiral HPLC has been examined using a chiral column

Experimental

Results and Discussion

1.52 C-6 methyl

Conflict of Interests