Synthesis and Antimicrobial Study of some Novel Schiff bases of Substituted Gallic Acid

A new series of novel substituted Gallic acid derivatives were synthesized by reacting methylated Gallic acid with hydrazine hydrate and then with various substituted aromatic aldehyde in mild and facile synthetic route to form various Schiff base derivatives.  Melting points of the synthesized compounds were determined by open capillary and are uncorrected. The purity of the compounds was checked using precoated TLC plates (MERCK, 60F) using chloroform: methanol (8:2) solvent system. The developed chromatographic plates were visualized under UV at 254nm. IR spectra were recorded using KBr on Josco FTIR model 8400 spectrophotometer, 1H NMR spectra in DMSO on a BRUKER FT-NMR instrument using TMS as internal standard. FAB mass spectra were recorded on JEOL SX 102 (DA-6000 mass Spectrometer) Data system using Argon (6KV.10MA) as the FAB gas. The designed compounds were screened for Antibacterial activity against Staphylococcus aureus and Escherichia coli and Antifungal activity against Aspergillus Niger in comparison with Ofloxacin and Fluconazole as standard to reveal the potency of synthesized derivatives. In accordance with the data obtained from antimicrobial activity, all the synthesized Schiff bases of substituted gallic acid have shown good activity against the tested microbes. Among these Schiff bases, compound bearing p-chloro group, o-chloro group, p-nitro group and m-nitro group has shown good activity against all the tested bacteria and fungi.