Synthesis and biological evaluation of coumarin clubbed thiazines scaffolds as antimicrobial and antioxidant

Article abstract of DOI:10.1007/s00044-018-2222-9

A new series of 4-methyl-6-nitro-2-oxo-2H-chroman-7yl-2-(4-(4-fluorophenyl)-6-phenyl-2H-1,3-thiazin-2-yl-amino)acetates 5a–j were synthesized from 6-nitro-4-methyl coumarinyl chloroacetate (5) and 2-amino thiazines (IIIa–j). The structure of the final compounds was adequately confirmed via spectroscopic techniques (IR, ¹H NMR, ¹³C NMR, Mass) and characterization of physical properties. Final compounds were screened for their antimicrobial, antitubercular, and antioxidant activities. Compounds 5c and 5h found to have antibacterial potency against E. coli with MIC values 50 μg/mL compared to standard drugs. Compound 5d demonstrated better antifungal potency (MIC = 200 μg/mL) against C. albicans when compared with griseofulvin. Compounds 5b and 5h found to be encouraging antitubercular (MIC = 62.5 μg/mL with 98–99% inhibition) against M. tuberculosis H₃₇Rv. The newly synthesized 5h and 5b were appeared to have high radical scavenging efficacies as 33.99 ± 0.301 and 35.35 ± 0.470 μg/mL ± SD of IC₅₀ values, respectively, in DPPH and ABTS bioassay.