INTRODUCTION Schiff’s bases, characterized by the presence of imine or azomethine (-C=N-) group, constitute an important class of organic synthetic compounds. Imines owing to –C=N- linkage are useful as precursors in diverse organic synthesis and exhibit wide spectrum of biological properties, viz. pesticidal 1 , fungicidal 2-4 , bactericidal 5,6 , bacteriostatic 7 , anticancer 8,9 , antiviral 10,12 etc. They have been reported as novel ligands informing complexes of unusual coordination numbers and isomeric structures with metals 13 , as dyes 14 and analytical reagents 15-16 . Vanillin containing Schiff’s bases act as a weak inhibitor of tyrosinase and display both antimutagenic and comutagenic ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org Est. 1984 An International Open Free Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2012, Vol. 28, No. (4): Pg. 1791-1796 Synthesis, Characterization and Antimicrobial Evaluation of some Schiff Bases and their Thiazolidinone Products DESTA GEBRETEKLE, ABI TADESSE, R. K. UPADHYAY* and AMAN DEKEBO Department of Chemistry, College of Natural and Computational Sciences, Haramaya University, Ethiopia. *Corresponding author E-mail: rkupadhyay14@gmail.com (Received: September 29, 2012; Accepted: November 10, 2012) ABSTRACT Six isomeric nitro- and methoxy anilines were condensed with vanillin to obtain Schiff’s bases. A new series of 2-(4-hydroxy-3-methoxy phenyl)-1-thiazolidinone derivatives were synthesized by the cyclocondensation of Schiff’s bases with mercapto acetic acid. The chemical structures of synthesized compounds were confirmed by elemental analysis, molecular weight determination, IR, 1 H & 13 C and DEPT-135 NMR spectral measurements. Antibacterial and antifungal activities were studied in vitro against staphylococcus aurous and Escherichia coli bacteria and Aspergillus niger and Rhizoctoia bataticola fungi by using Ampicillin and Bavistin reference drugs respectively. Key words: Schiff’s bases, Amines, Thiazolidinones, Bacteria, Fungi. properties in Escherichia coli 17 in addition to antimicrobial activities against various microbes and several pharmacological properties 1 . Thiazolidinone derivatives were reported to display antitumor 18 , antituberculor 19 , anti-HIV 20 , analgesic 21 , anti-inflammatory 20 , ulcerogenic 22 , and antibacterial 23-24 and antifungal 22 activities. Therefore it was envisaged that compounds containing vanillin and thiazolidinone moieties would result in compounds of interesting biological properties. In the present study vanillin was treated with isomeric nitro-and methoxy anilines to produce Schiff’s bases. The Schiff’s bases were subjected to cyclocondensation reactions with thioglycolic acid to produce 4-thiazolidinones. The chemical