The cyclization between 5-bromoisatoic anhydride (I) and D-phenylalanine methyl ester (II) in the presence of DMAP in refluxing pyridine produced the benzodiazepindione (III), which was further reduced to the benzodiazepine (IV) by treatment with borane in THF. Displacement of the bromide group of (IV) with cuprous cyanide in hot N-methylpyrrolidone furnished nitrile (V). Acylation of the aliphatic nitrogen of (V) with 2-thienylsulfonyl chloride (VI) gave rise to sulfonamide (VII). Finally, the title compound was obtained by reductive alkylation of (VII) with 4-formylimidazole (VIII) by means of either treatment with sodium triacetoxyborohydride or, in an improved procedure, using triethylsilane in the presence of trifluoroacetic acid.