合成路线1

The reaction of labeled 2-hydroxyacetophenone (I) with dimethyl oxalate and NaOMe gives 4-oxo-4H-1-benzopyran-2-carboxylic acid methyl ester (II), which is hydrogenated with H2 over Pd/C to yield 3,4-dihydro-2H-1-benzopyran-2(R)-carboxylic acid methyl ester (III). The optical resolution of (III) by chiral chromatography affords the labeled (R)-enantiomer (IV), which is condensed with benzylamine (V) to provide the corresponding amide (VI). The reduction of (VI) by means of NaAlH2(OC2H4OMe)2 gives the labeled chiral amine (VII), which is condensed with the butyl bromide derivative (VIII) to yield the tertiary amine (IX). Finally, this compound is debenzylated by hydrogenation with H2 over Pd/C to afford the target labeled Repinotan.