Synthesis and Antimicrobial Activity of 3-Substituted 8-Propenylbenzo[e][1,3]oxazines
G. M. Mehdiyeva
Abstract
A series of 1,3-benzoxazine derivatives were prepared by ternary Mannich condensation of 2-propenylphenol, formaldehyde, and primary amines (aniline, propylamine, hexylamine, and benzylamine). The product structures were confirmed by elemental analysis and by IR and NMR spectroscopy. The antimicrobial activity of the compounds against Staphylococcus aureus (two strains), Escherichia coli, Candida albicans, Shigella flexneri, Salmonella enterica, and Aspergillus niger was evaluated in 5, 15, and 35 mg L–1 solutions. The benzoxazine containing the benzyl fragment shows the best antimicrobial properties. To confirm the antimicrobial activity of the compounds in lower concentrations, serial dilution tests were performed, and the minimal suppressing concentration (0.035 mg L–1) was determined. The ultrastructure of an Escherichia coli cell in the presence of the compound with the benzyl substituent was examined by electron microscopy.