Computational study of optical properties, and enantioselective synthesis of di-substituted esters of hydantoic and thiohydantoic acids

Abstract

The title compounds with different optically active substituted ester of hydantoic and thiohydantoic were synthesized by the reaction of corresponding enantio-pure amino acids methyl ester hydrochloride with phenylisocyanate/thiocyanate in the presence of triethylamine. The duration of reaction was limited to avoid racemisation and produce high enantio-enriched compounds. Low values of ELUMO-HOMO gap 0.14, 0.16, 0.15, 0.15, and 0.10 eV were observed for compounds 1, 2, 3, 4, and 5, respectively indicate soft, and high reactivity compounds. Values of ELUMO-HOMO gap also show that the compounds can easily decompose spontaneously to their elements. The order of synthesized compounds based on increasing reactivity depends on LUMO-HOMO energy gap represent as follows; 5>1>3, 4>2. Thermodynamic energies have been calculated for synthesized compounds including Enthalpy and Gibbs free energy.