合成路线1

The synthesis of [14C]-labeled vigabatrin has been described: The reduction by known methods of pyroglutamic acid (I) to the alcohol (II) and its acylation with p-toluenesulfonyl chloride gives 5-(tosyloxymethyl)pyrrolidin-2-one (III), which by reaction with [14C]-labeled sodium cyanide in hot DMF yields 5-([14C]-cyanomethyl)pyrrolidin-2-one (IV). The reduction of (VI) with H2 over Pd/Al2O3 and treatment with dimethylamine affords 5-[2-(dimethylamino)ethyl]pyrrolidin-2-one (VI), which is oxidized with H2O2 in water to the N-oxide (VI). The treatment of (VI) with K2CO3 in refluxing xylene affords 5-([14C]-vinyl)pyrrolidin-2-one (VII), which is finally submitted to ring opening with hot 5 M aqueous HCl, followed by neutralization with triethylamine.