Synthesis, Characterization, and Theoretical Study of New Schiff bases from (S)-2-amino-3-(3,4-dihydroxyphenyl)-2-methyl propanoic acid as Initial Material of 1,3-Oxazepine-1,5-dione

Abstract

The present investigation introduced four Schiff bases derived from (S)-2-amino-3-(3,4-dihydroxyphenyl)-2-methylpropanoic acid, featured by the substituted benzaldehyde. These bases were utilized to prepare eight compounds of 1,3-oxazepine by direct condensation with phthalic anhydride and tetrachlorophthalic anhydride. The reactions were watched with thin layer chromatography (TLC) and all structures were characterized utilizing spectroscopy techniques like Fourier-transform infrared spectroscopy (FTIR) and some of them were characterized by Proton nuclear magnetic resonance (1H-NMR), Carbon nuclear magnetic resonance (13C-NMR), and CHN analysis techniques. Theory for the electronic structures was purposed to study the effects of substituted benzaldehyde on the electronic structure of prepared Schiff base by utilizing the Gaussian program. Theoretical outcomes point out that there is the effect of substituted groups on HOMO and LUMO energies of the prepared compounds.