The precursor triamine (VI) is prepared as follows. Ethanolamine (I) is protected as the N-Cbz derivative (II) upon treatment with N-(benzyloxycarbonyloxy)succinimide. Subsequent tosylation of (II) to yield (III), followed by displacement of the tosylate of (III) with trimethyl propanediamine (IV) furnishes the protected triamine (V). Then, Cbz group hydrogenolysis in (V) in the presence of Pd/C gives rise to triamine (VI).
Sulfonylation of pyrrole-2-carboxylic acid (VII) with 4-chloro-3-nitrobenzenesulfonyl chloride (VIII) in the presence of butyllithium leads to sulfonamide (IX). Chloride displacement in (IX) with hydrazine hydrate in refluxing THF affords the phenylhydrazine derivative (X). This is further coupled with isocyanate (XI) to produce the semicarbazide (XII). Finally, condensation of carboxylic acid (XII) with amine (VI), via activation as the mixed anhydride with isopropyl chloroformate, yields the title pyrrolecarboxamide.