N-Boc-pyrrolidine-3-carboxylic acid (II) was obtained by saponification of the corresponding methyl ester (I) with NaOH. Curtius rearrangement of acid (II) using diphenyl phosphoazidate, followed by trapping the resultant isocyanate with benzyl alcohol, produced carbamate (III). Deprotection of the benzyl carbamate (III) by hydrogenation over Pd/C gave amine (IV), which was acylated with benzenesulfonyl chloride (V) to form sulfonamide (VI). Removal of the Boc group of (VI) was then effected by treatment with trifluoroacetic acid. The resulting amine (VII) was converted to the title cyanamide by treatment with cyanogen bromide.