Synthesis, Spectral and Biological Studies of Schiff Bases Derived from 3-Aminophenol and Substituted Benzaldehydes

Abstract

Increased reports of hospital acquired infections as a result of microbial resistance reported to known antimicrobial and antiseptic agents have led the search of new highly active agents. A series of Schiff bases (L¹-L⁸) derived from 3-aminophenol and substituted benzaldehydes; 2-methoxybenzaldehyde, 2-hydroxybenzaldehyde, 2-chlorobenzaldehyde, 2-nitrobenzaldehyde, 4-methoxybenzaldehyde, 4-hydroxybenzaldehyde, 4-chlorobenzaldehyde and 4-nitrobenzaldehyde  have been synthesized and characterized based on elemental analysis, FT-IR, ¹H NMR and UV-Vis spectroscopy. The Schiff base ligands were screened for their in-vitro antibacterial activity against six pathogenic bacteria; Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Enterococcus faecalis and Klebsiella pneumoniae  using the disc diffusion method and 96-well micro-plate dilution method with ampicillin and sodium hypochlorite used as reference compounds. The antibacterial activity exhibit a dependence on both nature and position of substituent with compounds derived from 4- chlorobenzaldehyde (L⁷) and 4-nitrobenzaldehyde (L⁸) showing highest activity against the tested bacterial strains better than the reference compounds. These compounds can be employed as active ingredients in development of antibacterial/antispetic agents against these pathogenic organisms.