Acylation of 4-nitroaniline (I) with 4-fluorobenzoyl chloride (II) affords benzanilide (III). Catalytic hydrogenation of the nitro group of (III) employing Pt/C then gives amine (IV). Diazotization of (IV), followed by reduction with SnCl2 leads to hydrazine (V). Reaction of 5-chloro-2-pentanone (VI) with dimethylamine yields the amino ketone (VII). Finally, the title compound is obtained by Fisher indole synthesis from aryl hydrazine (V) and ketone (VII) under acidic conditions.

Condensation of 5-nitroindole (I) with 1-methyl-4-piperidone (II) in the presence of KOH produced tetrahydropyridinyl indole (III). Subsequent catalytic hydrogenation of (III) over Pd/C gave the 5-amino-3-piperidinylindole (VI). In a related procedure, 5-aminoindole (IV) was condensed with piperidone (II), and the resulting tetrahydropyridine (V) was hydrogenated to yield (VI). Aminoindole (VI) was finally condensed with 4-fluorobenzoyl chloride (VII) to produce the corresponding amide, which was isolated as the fumarate salt.

Acylation of 4-nitroaniline (I) with 4-fluorobenzoyl chloride (II) affords benzanilide (III). Catalytic hydrogenation of the nitro group of (III) employing Pt/C then gives amine (IV). Diazotization of (IV), followed by reduction with SnCl2 leads to hydrazine (V). Reaction of 5-chloro-2-pentanone (VI) with dimethylamine yields the amino ketone (VII). Finally, the title compound is obtained by Fisher indole synthesis from aryl hydrazine (V) and ketone (VII) under acidic conditions.

Acylation of 4-nitroaniline (I) with 4-fluorobenzoyl chloride (II) affords benzanilide (III). Catalytic hydrogenation of the nitro group of (III) employing Pt/C then gives amine (IV). Diazotization of (IV), followed by reduction with SnCl2 leads to hydrazine (V). Reaction of 5-chloro-2-pentanone (VI) with dimethylamine yields the amino ketone (VII). Finally, the title compound is obtained by Fisher indole synthesis from aryl hydrazine (V) and ketone (VII) under acidic conditions.