Ultrasound-assisted multicomponent synthesis of pyrido[2,3-d]pyrimidine derivatives and their DFT calculations: A green approach

Abstract

Pyrido[2,3-d]pyrimidines with their diverse biological potential became a highly significant class of N-containing heterocyclic compounds. They are prepared by the reaction of cinnamaldehyde and aminopyrimidine with 1,3-diketones (hydroxynaphthaquinone and hydroxycoumarin) by applying a knoevenagel condensation followed by a Michael addition multicomponent procedure. Although a few methods have been developed for synthesizing these compounds, they have advantages and disadvantages. Hence, developing a simple, efficient, and environmentally benign methodology for preparing these molecules in the presence of green reaction conditions is still in great demand. Therefore, this article describes an ultrasound-mediated multicomponent protocol to produce pyrido[2,3-d]pyrimidine under neat conditions. Further geometric optimizations, a frontier molecular orbital approach, and the molecular electrostatic potential for the synthesised chemical 4c and 5a were carried out using a computer density functional investigation. The DFT investigation was conducted using the B3LYP/6-311G (d,P) level of theory as the basis set.