Microwave assisted synthesis of coumarin-purine derivatives: An approach to anti-oxidant, DNA cleavage, crystal structure, DFT studies and Hirshfeld surface analysis.

An easy and efficient microwave-assisted protocol has been developed for the synthesis of coumarin-purine hybrids The newly constructed 1,3-dimethyl-7-((substituted)-2-oxo-2-chromen-4-yl)methyl)-1-purine-2,6(3,7)-dione derivatives were evaluated for their antioxidant activity by DPPH free radical-scavenging ability assay and DNA cleavage by using calf thymus. The compound shows the most excellent DPPH scavenging activity with a -OH substitution at C7 of coumarin ring. In addition, the structure of compound has been elucidated using single crystal X-ray diffraction technique. Theoretical calculations (DFT) were carried out using Gaussian09 program package and B3LYP correlation function. Full geometry optimization were carried out using 6-311G++(d, p) basis set and the frontier orbital energy were presented. Hirshfeld surface analysis was used for the intermolecular interactions in the crystal structure. The experimental result of the compound has been compared with the theoretical results and it was found that the experimental data are in a good agreement with the calculated values.