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 ...