Synthesis and characterization of new isatin hybrids based on isatin-coumarin hybrid as potent antioxidant, anti-inflammatory and antimicrobial agents

Iisatin hybrids have emerged as effective weapons against diseases. In this context, chalcone tethered isatin-coumarin hybrid 3 was synthesized and used as a building block for the preparation of a new series of isatin-pyrazole, isatin-bridged dibenzo-diazonin and isatin-coumarin hybrids 4–10 by reaction with ammonium acetate or primary aromatic amines. The hybrids 4–10 were linked with bioactive linkers named ethene, furan, pyrrole or its derivatives. Through another reaction route, the polyfused pyrano-indoles 11–13 were synthesized by one pot reaction of isatin - coumarin hybrid 3 with some primary amines having electron donating substituents. The chemical structures of the synthesized compounds were evaluated by infrared, nuclear magnetic resonance, MS and elemental analyses. The synthesized compounds were screened for their antioxidant, anti-inflammatory and antimicrobial effects. The results revealed that all the compounds have high antioxidant activity and some of these compounds provide anti-inflammatory effects close to that of indomethacin. While the antimicrobial effects were studied against both Gram - positive and Gram-negative bacteria, greater activity for compounds 3 and 6 was observed against Gram-positive bacteria (B. Subtilis). While compounds 3, 4, 6, 9 and 10 were active against Gram-negative bacteria (E. coli).