Boc-Nitroarginine (I) was activated as the mixed anhydride (II), which was further converted to the Weinreb amide (III) upon treatment with N,O-dimethylhydroxylamine. Reduction of (III) with LiAlH4 furnished N-Boc-nitroargininal (IV). This was reductively condensed with the mono-Boc-protected ethylenediamine (V) in the presence of sodium triacetoxyborohydride, yielding amine (VI). The Boc protecting groups of (VI) were finally removed by treatment with trifluoroacetic acid to provide the title compound.