Alkylation of 4-amino-3-nitrophenol (I) with 1-(2-chloroethyl)piperidine (II) provides ether (III). Subsequent nitro group reduction in (III) to afford diamine (IV) is performed by means of zinc powder in AcOH. Coupling of diamine (IV) with 2-chloroquinoline-3-carboxylic acid (V) furnishes amide (VI). Then, intramolecular cyclization of amino amide (VI) with Burgess reagent, followed by hydrolysis in boiling 6 M HCl gives rise to the title benzimidazolyl quinolinone.

Treatment of 2-chloroquinoline-3-carboxylic acid (I) with oxalyl chloride affords acid chloride (II), which is subsequently coupled with methyl 3,4-diaminobenzoate (III) to yield amide (IV). Intramolecular cyclization of amino amide (IV) with Burgess reagent in refluxing THF produces the benzimidazole (V). Then, acidic hydrolysis of both methyl ester and chloroquinoline functions of (V) gives rise to the carboxylic acid (VI). Coupling of (VI) with N-Boc-piperazine (VII) furnishes amide (VIII). The N-Boc protecting group of (VIII) is finally removed by treatment with trifluoroacetic acid in CH2Cl2.