Due to often-unexpected reactivities, 1,4-naphthoquinone derivatives are utilized as anti-fungal, antibacterial, and potential anticancer pharmaceuticals. Here we study the reactivity of 2-bromo-3-methyl-1,4-naphthoquinone toward primary and secondary amines. n the reaction with primary amines in methanol, contrary to our expectations, demethylation of 2-bromo-3-methyl-1,4-naphthoquinone generates 2-alkylamino-3-bromo-1,4-naphthoquinoneas the major product. Furthermore, secondary amines such as N-ethylmethylamine gave 2-methylamino-3-bromo-1,4-naphthoquinone, presumably as the secondary reaction product. The reaction mechanism is discussed.