Coupling of indanylacetic acid (IV) with L-thioproline ethyl ester (V) by means of EDC gave amide (VI). Subsequent saponification of the ethyl ester group of (VI) furnished (indanylacetyl)thioproline (VII). The title compound was finally obtained by coupling of acid (VII) with pyrrolidine (VIII).
Alternatively, the title compound was prepared by condensation between indanylacetic acid (IV) and thioprolylpyrrolidine (XI) either using EDC as the coupling reagent or via activation as the mixed anhydride (X) with pivaloyl chloride (IX) and triethylamine.
Aldol condensation between 1-indanone (I) and glyoxylic acid (II) in the presence of H2SO4 afforded keto acid (III). Catalytic hydrogenation of (III) over Pd/C furnished 2-indanylacetic acid (IV).