Synthesis of 2-(morpholin-4-yl)-5-(piperazin-1-yl)pyrido[4,3-d]pyrimidine derivatives, crystal structure, molecular docking studies, and anti-oxidant activities

Abstract

A series of new 10 novel compounds of 2-(morpholin-4-yl)-5-(piperazin-1-yl)pyrido[4,3-d]pyrimidine 8a-8j derivatives have been designed and synthesized. Target compounds were synthesized via Aza-Michael addition, intermolecular condensation followed by cyclization reactions of corresponding starting materials and intermediates. All the synthesized intermediates and target compound were well characterized using various spectral techniques (1H and 13C NMR, LCMS, IR) including crystal strcture. This process will be useful for the large-scale synthesis of substituted pyrido[4,3-d]pyrimidine derivatives without the use of column chromatography. The detailed molecular docking studies were performed which showed very promising binding scores obtained against cytochrome c peroxidase enzyme (PDB code: 2×08) for all the synthesized compounds. The results of preliminary bioassay indicated that all the synthesized compounds possess enhanced antioxidant activity compared to ascorbic acid standard.