Oxidative degradation of lactose 2,5-dichlorophenylhydrazone to galaro
se and 2-(2,5-dichlorophenyl)hydrazinecarbaldehyde with hydrogen perox
ide was found to give the best results in a weakly acidic medium under
catalysis of ammonium heptamolybdate. Of fourteen lactose hydrazones
evaluated, the best yields of galarose were obtained with 2,4-, 2,5-,
and 3,5-dichlorophenylhydrazones.