Abstract: | The related tripeptides glycyl‐L ‐prolyl‐L ‐glutamic acid (GPE) and glycyl‐L ‐2‐methylprolyl‐L ‐glutamic acid (G‐2‐MePE) were labelled with commercially available 1,2,3,4,5‐13C5, 2‐15N1]‐L ‐glutamic acid in 3 steps in excellent overall yield with high isotope incorporation. A related cyclic dipeptide was labelled with 2,2‐2H2, 2‐15N1]glycine giving a mixture of compounds resulting from deuterium scrambling. Copyright © 2006 John Wiley & Sons, Ltd. |