Thermal intramolecular redox reaction

When 4-nitro-7-phenylthiobenzofuroxan (195) was oxidized by m-chloroperbenzoic acid, an intramolecular redox reaction resulted in the formation of the benzofurazan sulfone (197).443 It has been shown that the sulfoxide (196) (and a number of analogous compounds) can be isolated, and that it is thermally converted into 197.444 This result is interesting in view of the reported failure to observe intramolecular oxygen transfer in a number of fused furoxans.35 0,445... 

---