Treatment of thiosemicarbazide hydrobromide (I) with ethyl bromide (II) in refluxing EtOH affords S-ethylthiosemicarbazide (III), which is then condensed with N-acetyl-ethylenediamine (IV) in refluxing EtOH to provide N1-(2-acetamidoethyl)-N3-aminoguanidine (V). Finally, the desired product is obtained by the formation of the corresponding hydrochloride salt by treatment of (V) with HCl in methanol. Alternatively the target compound can be obtained by reaction of N-acetylethylenediamine (IV) with cyanogen chloride in 2-propanol followed by treatment with anhydrous hydrazine.