Alkylation of vanillic acid methyl ester (V) with 3-chloropropyl tosylate (VI) in the presence of K2CO3 and Aliquat 336 gives the chloropropyl ether (VII). Subsequent electrophilic nitration of (VII) in hot HOAc affords the ortho-nitrobenzoate (VIII), which is further reduced to the amino benzoate analogue (IX) employing Fe/NH4Cl. Condensation of amino ester (IX) with dimethylformamide dimethylacetal provides adduct (X). This is then converted to the key quinoline derivative (XI) upon condensation with acetonitrile in the presence of butyllithium. Chlorination of (XI) with boiling POCl3 leads to the 4-chloroquinoline (XII). This is then coupled with the (imidazolylsulfanyl)aniline (IV) using pyridinium chloride in refluxing ethoxyethanol to furnish the anilino quinoline adduct (XIII). Finally, displacement of the chloride group of (XIII) with morpholine (XIV) in DMF provides the title compound.
Condensation of 3-chloro-4-fluoronitrobenzene (I) with the sodium derivative of 2-mercapto-1-methylimidazole (II) affords the diaryl sulfide (III). Subsequent nitro group reduction in (III) using iron dust and ammonium chloride provides the intermediate aniline (IV).