A comparative synthesis of the [DTrp6] LH-RH analog by the UNCA method in solution and by solid phase.

[DTrp6] LH-RH was prepared using urethane-protected alpha-amino and N-carboxyanhydrides (UNCAs) both in solution and by solid-phase methodologies. The yields and purities of the crude materials in both cases were high, as indicated by HPLC. The structures were confirmed by 1H NMR, FAB mass spectrometry and found to be identical to an authentic sample. Both synthetic samples were analytically pure by capillary zone electrophoresis.