Synthesis and enantiomeric resolution of tritiated (D,L)-3-hydroxykynurenine

The synthesis, purification and enantiomeric resolution of tritiated (D,L)‐3‐hydroxykynurenine are described. Bromination of racemic 3‐hydroxykynurenine, catalytic dehalotritiation and purification by ion pair, reverse phase HPLC afforded tritiated material of high radiochemical purity (99.8%) and moderate specific radioactivity (3.64 Ci/mmol). Enantiomerically pure (D)‐ and (L)‐stereoisomers were isolated using chiral HPLC conditions. The stability of the label toward isotopic exchange was assessed to be sufficient for biochemical studies.