合成路线1

Alkylation of (2-cyanophenyl)acetonitrile (I) with iodomethane under phase-transfer conditions leads to the alpha,alpha-dimethyl nitrile (II), which is further cyclized to imide (III) with 90% H2SO4. Subsequent nitration of homophthalimide (III) with HNO3/H2SO4 furnishes (IV) (1). Nitrophthalimide (IV) is reduced to the corresponding amine (V) by hydrogenation in the presence of Pd/C. This is then converted into acetamide (VI) by treatment with Ac2O. A second nitration reaction with cold HNO3 leads to the nitro amide (VII), which is further hydrolyzed with H2SO4 to the nitro amine (VIII). Hydrogenation of (VIII) over PtO2 furnishes diamine (IX). Coupling of (IX) with 2,6-dichlorophenyl isothiocyanate (X) gives thiourea (XI). Ring closure of amino thiourea (XI) to the benzimidazole derivative (XII) is carried out by treatment with DCC in refluxing THF. Partial reduction of the imide function of (XII) with NaBH4 in moist THF affords (XIII). Finally, rearrangement of (XIII) in concentrated H2SO4 at room temperature gives rise to the title compound (1,2).