Novel mixed ligand of 2,5-diamino-1,3,4-thiadiazole schiff base incorporating benzoic acid: Synthesis and antimicrobial activity

As part of our on-going research for more effective antimicrobial drug. A new mixed ligand has been synthesized. The starting material is Bithiourea which was synthesized by the reaction between semicarbazide hydrochloride and potassium thiocynate. The bithiourea produced was cyclised in the presence of 3% Hydrogen peroxide to produce 2,5-diamino-1,3,4-thiadiazole[L]. The new mixed 2,5-diamino-1,3,4-thiadiazole and Benzoic acid[L1] was then synthesized by Mannich reactions(Condensation). The chemical structures were confirmed by means of lemental analysis, IR, UV/Visible, 1H- and 13C-NMR. Others are thin layer chromatography and conductivity measurement. In-vivo evaluation of antimicrobial activity was carried out against the following micro-organisms: Escherichia Coli, Staphylococcus aureus, and Klebsiella pneumonia (Bacteria species). Aspergillus niger, Aspergillus flavus and Rhizopus species (Fungi species). Our findings, using the chemical, spectroscopic and physical properties showed that the two compounds coordinated in ratio 1:1 stoichiometry. Infrared spectral data also suggest that the ligand behaves as a tridentate ligand with N:S:O donor sequence. The mixed ligand exhibited greater biological activity as compared to the host compound. The difficulty of treating bacterial diseases induced us to assess the antimicrobial properties of this novel compound. This approach might provide interesting compounds with greater biological activity in pharmacological research.