Unusual Reaction of Azoxybenzenes with p-Toluenesulfonic Acid in Acetic Anhydride

Article abstract of DOI:10.1246/bcsj.55.1538

Treatment of azoxybenzene with p-toluenesulfonic acid in acetic anhydride gave tosylates of 4- and 2-(phenylazo)phenols, and the corresponding acetates as by-product, besides azobenzene.However, a similar reaction of 4,4'-difluoroazoxybenzene gave 2-tosyloxy-4,4'-difluoroazobenzene as rearrangement product, besides 4-fluorophenyl tosylate and 4-fluorophenyl acetate.Meanwhile, the reaction of 4,4'-diacetoxyazoxybenzene afforded 4-acetoxyphenyl tosylate and hydroquinone diacetate in high yields.These unique reactions involve C-N bond cleavage, and may proceed through a pathway involving formation of benzenediazonium ion as the key intermediate.