Microwave-Assisted Multicomponent Synthesis of Pyrrolo [2, 3-d] Pyrimidinone Derivatives and Their DFT Calculations

Herein we have reported a green and environmentally benign methodology for synthesizing novel pyrrolo[2,3-d] pyrimidine derivatives under microwave-assisted reaction conditions. The desired product was obtained with an excellent yield (80-90%) within 30 minutes only. The characteristic features of this protocol were the use of green reaction conditions, high atom economy, less reaction time, excellent yields, no use of specific purification processes, no column chromatography, etc. Later, theoretical studies like DFT were also performed on each newly synthesized product (4a-e) using B3LYP (Becke-Lee-Yang-Parr) functional and 6-31+G (d,p) to get spot onto the geometry, electronic transitions, and spectroscopic properties theoretically that has been compared with the encountered experimental ones. The molecular electrostatic potential surface, Band gap (_E), Chemical Potential (μ), Chemical hardness (n), Ionization Potential (I), Electron Affinity (A), Electronegativity (X), potential, Electrophilicity index (ω) are computed in order to find out electrophilic and nucleophilic sites. All the newly synthesized pyrrolo[2,3-d] pyrimidine derivatives were subjected to DPPH, ABTS, and TAC for antioxidant activities. 4b and 4d showed maximum potent antioxidant activity.