Mechanism of autoreduction of bis(4-methoxyphenyl)-oxoammonium perchlorate in aqueous alkali

Autoreduction of bis(4-methoxyphenyl)oxoammonium perchlorate in aqueous alkali follows a mechanism different from that generally accepted for diaryloxoammonium salts. Bis(4-methoxyphenyl)-oxoammonium cation undergoes hydrolysis to the corresponding quinone imine oxide and methanol, the latter gives rise to methoxide ion which reduces the oxoammonium cation to intermediate bis(4-methoxyphenyl)-hydroxylamine. The reaction of bis(4-methoxyphenyl)hydroxylamine with the initial cation yields bis-(4-methoxyphenyl)nitroxyl, and the quinone imine oxide undergoes disproportionation to N-(4-methoxyphenyl)-1,4-benzoquinone imine and oxidation products.