PURPOSE: To provide the novel compound useful as a chelating therapeutic medicine for iron-excessive diseases.

CONSTITUTION: This compound is expressed by formula I (X is 2,3- dihydroxyphenyl of formula II; lysine is L-isomer or D-isomer; n is 2-4), for example N[Nα,N-bis-(2,3-dihydroxybenjoyl)-L-lysinyl]-N'-(2,3-dihydroxybenzoyl)- alkylenediamine. The compound of formula I is synthesized by reacting L-lysine hydrochloride with di-tert-butyl dicarbonate [(BOC)2O] in water-dioxane and subsequently passing through a compound of formula III, etc.