合成路线1

1) The diazotation of 4-amino-N-methylbenzenemethanesulfonamide (I) with NaNO2-HCl followed by reduction with SnCl2 gives the 4-hydrazino compound (II), which is condensed with (phenylthio)acetaldehyde (III) in ethanol yielding the ethylideneamino compound (IV). The cyclization of (IV) with HCl in ethanol affords N-methyl-3-(phenylthio)-1H-indole-5-methansulfonamide (V), which is desulfurized with RaNi in refluxing ethanol-water to give N-methyl-1H-indole-5-methanesulfonamide (VI). The reaction of (VI) with oxalyl chloride and dimethylamine yields the oxalyl derivative (VII), which is finally reduced with LiAlH4 in refluxing THF.