The condensation of tert-butoxycarbonyl-D-alanine (I) with ethylenediamine (II) gives the corresponding protected diamide (III), which is deprotected in acidic medium to the diamide (IV). The reduction of (IV) with diborane in THF yields the (R,R)-4,7-diazadecane-2,9-diamine (V), which is finally condensed with 3-nitronaphthalene-1,8-dicarboxylic acid anhydride (VI) in refluxing ethanol and salified with methanesulfonic acid.