In-silico Studies, Synthesis and Antioxidant Studies of Different Substituted 7-Phenyl-5-(Thiophen-2-Yl)- 2-Thioxo-2,3-Dihydropyrido[2,3-D]Pyrimidine-4(1h)- Ones

Background: Free radicals and ROS which are formed in normal physiological conditions, damages the cells if it is not eliminated by endogenous system which causes oxidative stress. Pyridopyrimidines are important molecule in heterocyclic chemistry, gaining interest because of their biological and pharmacological activities, especially for their potential anti-tumor, antibacterial and tyrosine kinase inhibitors, among other pharmacological properties along with anti-oxidant properties. Materials and Methods: In the current study, novel pyridopyrimidines derivatives i.e different substituted 7-phenyl-5-(thiophen- 2-yl)-2-thioxo-2,3-dihydropyrido[2,3-d]pyrimidine-4(1H)-one(3a-p) were synthesized to develop potent anti-oxidant agent. Based the in-silico studies, especially depending on the docking score, 8 compounds were selected for the synthesis and evaluated for their anti-oxidant potency. Selected compounds were synthesized using mercapto-4- hydroxy-6-amino pyrimidine (1) and substituted α, β- unsaturated ketones(2a-p). Results: Synthesized compounds were characterized by IR, NMR and Mass spectra. In-vitro antioxidant studies were performed for 8 best scored compounds by DPPH assay and nitric oxide inhibition assay. From the in-vitro result, compound 3j, 3a, and 3o are considered as promising molecules. Conclusion: The promising activity may be because of presence of electron releasing group (3a- p-OH, 3o- p-NH2) and electron withdrawing group (3jp- CF₃) which can be considered as lead molecules for the further discovery