The reaction of 4-fluorophenylhydrazine hydrochloride (I) with N-carbethoxy-4-piperidone (II) under Fisher's conditions affords N2-carbethoxy-8-fluoro-2,3,4,5-tetrahydro-1H-pyridol[4,3-b]indole (III). Treatment of (III) with Claisen's alkali affords the N-2 unsubstituted 8-fluoro-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole (IV), which is finally condensed with 3-pyridinylpropyl bromide hydrobromide (V) in DMF in the presence of triethyl amine (TEA). Compound (V) is obtained by refluxing 3-pyridinylpropanol with 48% hydrobromic acid.