Abstract

DESIGN AND BIOLOGICAL SCREENING OF SOME NOVEL FORMAZAN DERIVATIVES FROM SCHIFF BASES OF GALLIC ACID

Kumara Prasad S. A.*, Subrahmanyam E.V.S., . Shabaraya A.R.,

Abstract

A series of novel formazans were synthesized by multistep reaction starting from Gallic acid (3,4,5-trihydroxy benzoic acid). Gallic acid, after esterification, on reaction with hydrazine hydrate was converted into galloyl hydrazide. This intermediate compound underwent Schiff reaction with different aromatic aldehydes to yield ten Schiff bases. This Schiff bases on condensation with diazonium salts of various substituted anilines yielded formazan derivatives. All the compounds were obtained in good yield in the range of 60-80%. 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 Pharmacological screaning of all the synthesised compounds was performed to test their analgesic, antiinflammatory and anticonvulsant activity. Also 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 Pharmacological and Antimicrobial screaning, all the synthesized Formazan derivatives have shown good Biological activity.

Keywords: Biologicall activity, Aromatic aldehyde, DMSO, Gallic acid, Formazan