合成路线1

Treatment of tetrahydrocarbazolone (I) with formaldehyde and dimethylamine in EtOH provides tertiary amine (II), which is then methylated with refluxing iodomethane to furnish methanaminium iodide (III). Condensation of (III) with 2-methylimidazole (IV) in DMF affords free base (V), which is converted into the desired product, the hydrochloride dihydrate, by treatment with HCl in isopropanol/water. Alternatively, free base (V) can be obtained by other related procedures: (a) treatment of methanaminium iodide (III) with sodium carbonate in water to furnish methylene derivative (VI) followed by condensation with 2-methylimidazole (IV) in refluxing water; (b) conversion of (VI) into chloromethyl derivative (VII) by treatment with ethereal HCl in CHCl3, followed by reaction of (VII) with 2-methylimidazole (IV) in DMF; (c) treatment of dimethylamino derivative (VIII) with 2-methylimidazole (IV) in refluxing water; or (d) methylation of carbazolone (IX) with dimethylsulfate and sodium hydride in DMF.