CONVENIENT PREPARATION OF BOC-L-[4-N-15]ASPARAGINE AND BOC-L-[5-N-15]GLUTAMINE FOR APPLICATION IN PEPTIDE-SYNTHESIS

The title compounds have been prepared by a simple and economical proc edure from the corresponding Boc-protected alpha-benzyl esters and [N- 15]ammonia with N,N'-carbonyldiimidazole as coupling agent. Catalytic hydrogenolysis furnished both labelled products in high overall yields suitable for synthetic work.