Reactivity of 2,2‐disubstituted quinazolinone towards electrophilic substitution: First in silico design to verify experimental evidence of quinazolinone‐based new organic compounds

Abstract

In a previous report, we have already synthesized dinitro and dibromo derivatives of 2,2-disubstituted-quinazolin-4(1H)-one by a facile method. In order to give insight to our experimental results, we herein report on the theoretical investigations of reactivity of synthesized quinazolinone toward bromination and nitration by using density functional theory (DFT) calculations. The optimized molecular geometries of these compounds by using the B3LYP/6-31G (d, p) method have been compared with their X-ray structures, which are in good agreement. The correlation between the experimental and computational geometrical data is above 90% and root mean square deviation (RMSD) is low ranging from 0.04% to 0.9% except N1-H1 and N2-H2 bond where RMSD goes to 1% due to hydrogen bonding between N1-H1 …..O1 = C1 and N2-H2 … . O1 = C1. The Mullikan charge distributions at the different atomic sites have been computed and nucleophilic site are guessed by molecular electrostatic potential (MEP) map. In addition, frontier molecular orbitals of these compounds were discussed at the same level of theory, confirming the nucleophilic sites at position 6 and 8 of 4-quinazolinone.