Ethyl (S)-indoline-2-carboxylate (I) is treated with methanolic ammonia to yield amide (II). After protection of indoline (II) as the N-acetyl derivative (III), dehydration of the carboxamide moiety by means of trichloroacetyl chloride and triethylamine leads to nitrile (IV). Subsequent treatment of nitrile (IV) with ethanolic HCl affords imidate (V), which is further condensed with 1-amino-2-butanone (VI) producing imidazole (VII). Deacetylation of (VII) in refluxing 6 N HCl, followed by coupling of the resultant amine (VIII) with acid fluoride (IX) yields amide (X). Finally, N-Boc group cleavage in (X) by means of trifluoroacetic acid furnishes the title compound.