Rearrangements Involving Cleavage of an N—S Bond

The reaction of 2-substituted-5-aroyl-isothiazol-3-ones (214) with hy-droxylamine or arylhydrazines gives the 1,2,5-oxathiazoles 216 (Z = O) or 1,2,3-thiadiazoles 216 (Z = NAr ), as a result of a spontaneous rearrangement of unisolated oximes 215 (Z = O) or arylhydrazones 215 

Ar = P-CIC6H4 Ar = p-MeC6H4, P-FC6H4, P-CIC6H4, 3.5-C12C6H4, 2.6-C12C6H4 

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