New synthesis of 3,5-diaryl-1,2,4-oxadiazoles containing a sulfonyl chloride or sulfonamide group

A procedure has been developed for the indirect introduction of sulfonyl chloride and sulfonamide groups into 3,5-diaryl-1,2,4-oxadiazoles via acylation of N′-hydroxybenzimidamide with aromatic and heterocyclic sulfocarboxylic acid dichlorides. The acylation selectively involves the carbonyl chloride group, regardless of the dichloride structure.