合成路线1

The reaction of 4-ethyl-3,5-dimethoxybenzaldehyde (I) with (ethoxycarbonylmethyl)triphenylphosphonium bromide (II) by means o butyllithium in THF gives the acrylate (III), which is allowed to react with nitromethane/triton B in hot methanol yielding the 4-nitrobutyrate (IV). The reduction of (IV) with H2 over RaNi in ethanol affords the 4-aminobutyrate (V), which is cyclized to the pyrrolidinone (VI) by means of p-toluenesulfonic acid in refluxing ethanol. The methylation of (VI) with NaH/methyl iodide in THF gives the corresponding N-methylpyrrolidinone (VII), which is condensed with tert-butyl bromoacetate (VIII) by means of butyllithium/diisopropylamine in THF yielding the intermediate (IX). The reduction of the ketonic grupof (IX) with the complex borane/THF in THF affords the pyrrolidineacetate ester (X), which is cyclized by means of polyphosphoric acid (PPA) at 120 C giving the benzisoindole (XI). Finally, this compound is selectively demethylate by menas of BBr3 in dichloromethane.