1H-Nmr Studies of Folded Conformation in Hydantoin and Thiohydantoin Derived from S-Methyl and S-Ethyl L-Cysteine

I. Attia; M. A. Sayed; S. El-Nagdy

Article | Open Access

1H-Nmr Studies of Folded Conformation in Hydantoin and Thiohydantoin Derived from S-Methyl and S-Ethyl L-Cysteine

I. Attia, M. A. Sayed and S. El-Nagdy

Department of Chemistry, Faculties of Engineering and Science, Aim Shams Unherisity, Abbassia, Cairo (Egypt)

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ABSTRACT:

3-phenyl hydantoin and thiohydantoin derived from S-methyl and S-ethyl L-cysteine were prepared. 1H-NMR spectra showed well resolved ABX system for these compounds. Using calculated values of the vicinal coupling constants 3J/H∝ Hβ/ the amounts of conformers on the C∝—βC bond were estimated. The stabilized conformer is folded one (F). An investigation of the compounds at different temperatures led to calculate the thermodynamic parameters for the conformational equilibria on the C∝—βC bond.

KEYWORDS:

Studies; S-Methyl; S-Ethyl; L-Cysteine