Synthesis of Pyrazole Carboxylic Acid via Cobalt-Catalyzed Liquid Phase Oxidation

Abstract
In the presence of catalytic amount of cobalt acetate(II), manganese acetate(II) and bromide ion, the selective oxidation of 3,5-dichloro-1,4-dimethylpyrazole with molecular oxygen afforded 3,5-dichloro-1-methylpyrazole-4-carboxylic acid in more than 95% yield.