An Efficient Approach for the Esterification of 5-Chloroquinolin-8-ol through Steglich Reaction and their Antioxidant Applications

Esterification of organic molecules offers a critical process for chemical modifications. Among the various methodologies, Steglich conditions gave easiest and mild pathways. O-Acylation of 5-chloro-8-hydroxyquinoline with different acylating counterparts has been investigated. Among the various catalysts used, N,N-dimethylpyridin-4-amine (DMAP) in the presence of N,N′-dicyclohexyl carbodiimide (DCC) displayed a plausible synthetic approach through the application of Steglich esterification reaction for the synthesis of 5-chloroquinolin-8-yl-benzoates (3a-h) with good yields. The structures of the synthesized compounds were characterized through NMR, IR and MS spectral data. In present study, 5-chloro-8-hydroxy quinoline and its derivatives (3a-h) bearing various substituents were investigated for their antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The findings revealed that the derivatives act as imminent candidates to be further developed as antioxidant agents.