Osmium [VIH]-catalyzed oxidation of indoles by potassium hexacyanoferrate [III] in alkaline media: a kinetic and mechanistic study

ABSTRACT

The reaction of indoles with Os [VIII] catalyzed hexacyanoferrate [III] in alkaline media to produce the corresponding oxindole has been studied at constant temperature and ionic strength. The reaction followed first order kinetics with respect to [indole], [OH[-] and [Os [VIII]], fractional order in [Fe[CN][6][-3]. The effects of added electrolytes, potassium hexacyanoferrate [II], relative permitivity and temperature have also been studied. A mechanism consistent with the kinetic data is proposed. Furthermore, the structural influence of the indoles on the reactivity has been discussed