Mild and recyclable catalytic oxidation of pyridines to N-oxides with H2O2 in water mediated by a vanadium-substituted polyoxometalate

A vanadium-substituted polyoxometalate, K-6[PW9V3O40]center dot 4H(2)O, was used as a recyclable and effective catalyst for the oxidation of pyridines. The reactions were successfully conducted in water under mild conditions. The catalyst could be easily recovered and reused.