In a previous paper, 15 it has been described how the usual synthetic methods of peptides containing C-terminal glutamine are attended with many difficulties, and how the introduction of a xanthyl group into the 7-amide nitrogen is effective in reducing these troubles. The present study is concerned with another approach to the same problem using ap-nitrobenzyl 7-methyl glutamate as an intermediate. It is known that the/j-nitrobenzyl ...