合成路线1

Condensation of isonicotinamide (I) with 1-chloro-2,4-dinitrobenzene (II) gave quaternary pyridinium salt (III). This was further converted into pyridinium salt (V) by treatment with 2-methoxyaniline (IV) in MeOH. Catalytic transfer hydrogenation of the pyridine ring of (V) provided piperidine (VI). The amide function of (VI) was then reduced to amine (VII) using either borane-dimethyl sulfide complex or LiAlH4. Condensation of 4-chlorocatechol (VIII) with epichlorohydrin (IX) in aqueous KOH produced a mixture of regioisomeric benzodioxans (X) and (XI), from which the major 7-chloro isomer (X) was isolated by flash chromatography after treatment with tosyl chloride and pyridine yielding tosylate (XII). This compound was finally coupled with amine (VII) in the presence of K2CO3 and KI in boiling acetonitrile.