(CAS NO.: ), with its systematic name of (-)-(3S,4R)-3-(1,3-Benzodioxol-5-yloxymethyl)-4-(4-fluorophenyl)piperidine, could be produced through many synthetic methods.

Following is one of the synthesis routes: 4-Nitropyrocatechol (I) is cyclized with [14C]-CH₂Br₂ by means of cesium carbonate in DMSO, giving 3,4-(methylenedioxy)nitrobenzene (III). The reduction of (III) with H₂ over Pd/C in ethanol yields the corresponding aniline (IV), which is treated with HNO₂, copper nitrite and cuprous oxide to afford the corresponding phenol (V). The condensation of (V) with (3S,4R)-4-(4-fluorophenyl)-1-methyl-3-(phenylsulfonyloxymethyl)piperidine (VI) by means of sodium methoxide in methanol gives [14C]-labeled 1-methylparoxetine (VII), which is finally demethylated with vinyl chloroformate and potassium carbonate in dichloroethane.