On the preparation of L-[2,3-3H2]phenylalanine and L-[2,3-3H2]tyrosine

Abstract

Specimens of L-[2,3-³H₂]phenylalanine and L-[2,3-³H₂]tyrosine, prepared via reduction of acylaminocinnamic derivatives with tritium gas, have been degraded to establish the tritium labelling patterns. Both amino-acids were found to be labelled approximately equally at C-2 and -3 with the tritium at C-3 in predominantly the pro-S position. Catalytic hydrogenation of (Z)-(α-acetamido[β-²H]cinnamyl)-L-glutamic acid was used to demonstrate, by n.m.r. spectroscopy, the stereochemical course of the tritiation.