Transformation of the sydnone ring into oxadiazolinones. A convenient one-pot synthesis of 3-aryl-5-methyl-1,3,4-oxadiazolin-2-ones from 3-arylsydnones and their antimicrobial activity.

3-Arylsydnones (Ia-u) have been converted into the corresponding 3-aryl-5-methyl-1,3,4-oxadiazolin-2-ones (IIIa-u) by a single-step reaction with bromine in acetic anhydride. In the preliminary screening of all these compounds, the halogen-substituted derivatives have shown antimicrobial activities equal to those of the standard drugs used.