Synthesis and Antimicrobial activity of Formamidine disulfide Schiff bases and their corresponding 1,3-oxazepines

Formamidine disulfide was synthesized by oxidizing thiourea in the presence of potassium permanganate. It was then reacted with various aldehydes to give formamidine disulfide Schiff bases. Each Schiff base was then condensed with maleic anhydride and phthalic anhydride to yield corresponding 1,3-oxazepine derivatives respectively. The phthalic anhydride derivative of benzaldehyde Schiff base was not synthesized as a result of low yield. The antimicrobial activities of the schiff bases were better than the oxazepines. Those of the maleic anhydride oxazepine derivatives were better than those of the phthalic anhydride oxazepine derivatives. This shows that the imine group (-C=N-) is responsible for antimicrobial activity in schiff bases. More so, the best schiff base is the 3-nitro benzaldehyde derivative that is; 1,1’{disulfanediylbis[carbonimioylnitrilo (Z)methylylidene]}bis(3-nitrobenzene), for all the organisms used at the lowest concentration (@25mn/dl). At 200mg/dl, which is the highest concentration used, all the compounds synthesized show a level of activity. In between these two extreme concentrations antimicrobial activity of these analogues against E.coli began to show a trend.