Peptides. VII. Some Sulfonates of Strongly Acidic N-Hydroxy Compounds as Novel Coupling Reagents

Sulfonates of strongly acidic N-hydroxy compounds such as 6-chloro-1-(p-chlorophenylsulfonyloxy)benzotriazole have been found to be excellent coupling reagents for amide bond formation. Amides can be prepared through either an active ester or a mixed anhydride according to the chosen procedure. Several active esters and protected di- and tripeptides prepared are listed in the Tables. Racemization, possible side reactions, and reaction pathways of the amide bond formation have also been discussed.