It was found that the oxygen atom in amine N-oxides facilitated dehydrogenation of the corresponding amines. Reaction of amine N-oxides with the corresponding amines, using the platinated palladium-carbon catalyst, under the conditions listed in Table I will give in a good yield the homologs of III, VII, and IV, important as the analytical reagents for heavy metals. Dehydrogenation reactuon of VI with palladium-carbon catalyst gives 2, 2'-diquinolyl in 96% yield and 2, 2'-dilepidyl in 60% yield. In this case, addition of a corresponding amine N-oxide results in progress of the reaction under a more mild condition. The platinated palladium-carbon catalyst used in these reactions was found to give markedly different yield of products according to the amount of platinum added.