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)

Abstract

Some new N-[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 upon 1H 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.

Study on Synthesis and Antimicrobial Activities of Some Micheal-Type Addition Compounds

“…It should also be noted that for IIa-IIg diastereomeric compounds, it was observed that -CH2-S-protons were coupled with -CH-COO-protons and appeared as multiplets were seen in the experimental section. These observations were consistent with those reported in the literature [16,26,27]. The retention times of the peak in the samples and the ESI-LC/MS spectrum are evidence that IIa-IIg is pure and suggested chemical structures.…”

Synthesis and characterization of novel biheterocyclic compounds from 3‐alkoxy‐1H‐pyrazole‐4‐carbaldehydes via multicomponent reactions

“…The NMR spectra of the (4 S ‐) and (4 R )‐enantiomers of compound 11 were identical. However, compounds 13 or 14 were obtained as mixtures with unequal compositions of two diastereomeric pairs, which were differentiated based on 1 H, 13 C, and 15 N NMR spectral data (Figures S53–S55, S57–S59) in similarity to other stereochemical investigations [59]. The 5‐H methine proton signals in the 1 H NMR spectra were integrated to calculate the ratios of the major to minor diastereomers as 52%: 48% and 57%: 43% for compounds 13 and 14 , respectively (Figure 3).…”

A Cyclic Disulfide Diastereomer From Bioactive Fraction of Bruguiera gymnorhiza Shows Anti–Pseudomonas aeruginosa Activity

“…Generally, physical or chemical properties of these molecules can differ, and consequently, stereochemistry of the metabolite shows an impact on the difference in the biological action. Hence, metabolites with different isomers can differ in terms of either less or more activity toward pathogens ( Hutt and O’Grady, 1996 ; Tessema et al, 2013 ; Demir-Ordu et al, 2015 ). So far, in our study, we have not achieved complete separation of these two diastereomers due to the lack of a sufficient amount of sample, and hence, the entire study was conducted based on a mixture.…”