Experimental and theoretical studies of diethyl 2-(ter-butylimino)-2,5-dihydro-5-oxo-1-phenyl-1H-pyrrole-3,4-dicarboxylate using DFT calculations

Abstract

In this study, diethyl 2-(ter-butylimino)-2,5-dihydro-5-oxo-1-phenyl-1H-pyrrole-3,4-dicarboxylate compound 1 is synthesized and characterized by FT-IR, ¹H and ¹³C NMR spectroscopy. The DFT calculations are carried out for compound 1 by B3LYP and PBE1PBE methods. The bond lengths, bond angles, dihedral angles, charge density on the atoms of 1 are calculated. A comparison of the DFT calculations indicate that the B3LYP method with the 6-311G++(d,p) basis set can give accurate results. The ¹³C NMR and ¹H NMR chemical shifts of 1 are calculated and compared with the available experimental data on the molecules. The nuclear independent chemical shift (NICS) calculations are utilized for the pyrrole ring in compound 1.