The synthesis of 5‐hydroxyindole‐3‐(‐2‐D2‐acetic acid) and α,α′,β,β′‐D4‐5‐hyoroxytryptamine

Deuterium Labelled 5‐hydroxyindole‐3‐acetic acid and 5‐hydroxy‐tryptamine have been sythesized by a modification of the procedure previously described by Ek and Witkop (9) for the nondeuterated analogues. The deuterium is introduced by a solvent exahange reaction and by reduction with lithium aluminium deuteride. The isotopic yield was > 99%.