Cyclization of D-tryptophan methyl ester (I) with piperonal (II) by means of TFA in dichloromethane gives, after separation of the undesired trans-isomer by flash chromatography, the (1R,3R-cis)-pyrido-indole derivative (III). The acylation of (III) with chloroacetyl chloride (IV) and NaHCO3 in chloroform yields the chloroacetyl derivative (V), which is finally cyclized with methylamine in methanol.