Design, synthesis and biological evaluation of novel pyrido-[2,3-d]-pyrimidin-2-amine analogues as antimycobacterial agents

Abstract

Thirty-eight novel Pyrido-[2,3-d]-pyrimidin-2-amine derivatives (P1-P38) were designed, synthesized, and their structures confirmed using analytical techniques viz., 1H NMR, 13C NMR, and mass spectrometry. Using the Microplate Alamar Blue Assay (MABA), the final derivatives, P1-P38, were tested for their anti-mycobacterial activity against the Mycobacterium tuberculosis (Mtb) H37Rv strain. Amongst all the assessed compounds, P35 displayed significant inhibition with MIC 7.18 μg/mL. The remaining compounds exhibited MIC from 18.11 to >100 μg/mL. The potent compounds with MIC 〈 40.96 μg/mL, were evaluated for toxicity on HEK293T a normal human embryonic kidney cell line. The most active compound P35 exhibited a selectivity index 〉 20, proving its selective behavior towards Mtb H37Rv strain than human cells. To further evaluate the binding pattern in the active site of Thymidylate Kinase (TMPK) from Mtb (PDB-1G3U), a molecular docking analysis of compound P35 was performed using the glide module of Schrodinger software. Finally, molecular dynamics simulations were performed for 100 ns in order to elucidate the stability, confirmation, and intermolecular interactions of the co-crystal ligand and significantly active compound P35 on the selected target protein.