5-Nitrobenzofuran-2-carboxylic acid (I) is coupled to 4-nitrophenol (II) in the presence of EDC to produce the p-nitrophenyl ester (III). Subsequent acylation of the duocarmycin derivative (IV) with active ester (III) leads to amide (V). Cyclopropane ring opening in (V) with HCl in DMF furnishes the chloromethyl derivative (VI). The nitro group of (VI) is then reduced by catalytic hydrogenation, yielding amine (VII). Acylation of (VII) with 7-nitroindole-2-carboxylic acid (VIII) affords the corresponding amide (IX)

The phenolic hydroxyl group of (IX) is acylated by 4-nitrophenyl chloroformate (X), producing carbonate (XI). Then, displacement of the 4-nitrophenoxy group of (XI) with N-methylpiperazine (XII) yields carbamate (XIII). Finally, nitro group reduction in (XIII) gives rise to the title compound