Active esters have been widely used as versatile synthetic intermediates, especially in peptide synthesis, and the de- velopment of a variety of active esters has been studied extensively. 1~ During our continuing studies on the synthetic utility of di-2-pyridyl carbonate (2-DPC),3 we have found that it can be effectively used as a coupling reagent for the preparation of various active esters such as 2-pyridyl, succini- mido, phthalimido, benzotriazol-1-yl, and p- ...
