Design, multistep synthesis and in-vitro antimicrobial and antioxidant screening of coumarin clubbed chalcone hybrids through molecular hybridization approach

In the present study we designed and synthesized 26 coumarin clubbed chalcone hybrids (1–13 and 14–26) in good yields (54.32–74.25%) and further tested for their antimicrobial and antioxidant activities considering the potential bioactivities of these two pharmacophores. All Spectroscopic techniques including FT-IR, ¹H NMR, ¹³C NMR and mass were used to characterize the compounds. The antimicrobial and antioxidant activities of these compounds were performed by agar well diffusion method and DPPH free radical assay respectively. The compounds elicited considerable antimicrobial and potential antioxidant activities. Bioactivity data designated that the compounds 1 and 7 with no and 4-Cl substitution on the phenyl ring of coumarin clubbed chalcones with 3,4-dihydropyrimidine-2-one displayed antibacterial activity with minimum inhibitory concentration (MIC) value of 10 µM and 17 µM against Staphylococcus aureus and MIC value of 8 µM and 13 µM against Escherichia coli and antifungal activity with MIC value of 10 µM and 11 µM against Aspergillus niger respectively. On the other hand, coumarin clubbed chalcones with 3,4-dihydropyrimidine-2(1H)-thione scaffold (14–26) exhibited potential antioxidant activity. Among them, compounds 22 containing electron releasing 2-OH substituent was the most active with 77.92% scavenging activity, followed by 14 and 26 (75.22% and 71.32%). The promising leads evolved through this investigation are important for the future development of novel and potential antioxidant compounds.