Synthesis of new 1,2,4-oxadiazolidin-3-ones by cycloaddition of 2-alkyl-3-aryloxaziridines with chlorosulfonylisocyanate

2-Alkyl-4-chlorosulfonyl-5-aryl-1,2,4-oxadiazolidin-3-ones 5 were prepared via cycloaddition of 2-alkyl-3-aryloxaziridines 3 with chlorosulfonylisocyanate. The structure of 5 was proved by a crystal X-ray analysis. Hydrolysis of 5 in the presence of triethylamine afforded 2-alkyl-5-aryl-1,2,4-oxadiazolidin-3-ones 6.