SYNTHESIS AND BILOGICAL SIGNIFICANCE OF 1,2,4-OXADIAXOLIDIN-5-ONE Chimdi kalu, Austin Miller and Dr. Abbas G. Shilabin Department of Chemistry, East Tennessee State University, Johnson City, TN 37614. ABSRTACT Due to the challenge posed by microbial resistance to broad spectrum of antibiotics, there has been a great need to synthesize of a novel compound which has a different mechanism of action on microbial activity. 1,2,4-oxadiaxolidin-5-One constitute an important class of compound with tremendous potential as pharmaceutical and otherwise biologically relevance substance due to the fact that its five member ring is a configurationally stable building block. This unit is found in other compound like alkaloids, with vast medical application. This study describes the synthesis of 1,2,4-oxadiaxolidin-5-one in two-step procedure using nitroethane and benzaldehyde as starting materials to produce nitrone, which in turn undergoes 1,3- dipolar cycloaddition with phenyl isocyanate to give 1,2,4-oxadiaxolidin-5-one. The product was characterized using proton NMR and GC-MS. There is an ongoing investigation on the summary of some important inhibitory activity against class A β-lactamase by 1,2,4-oxadiaxolidin-5-one heterocyclic core structure to provide effective antimicrobial β-lactamase inhibitors, hence, solving the problem of microbial resistance to currently used antimicrobial drugs.