A new condensing agent, N, N′-carbonyldi [2 (3H)-benzoxazolethione](3), was readily prepared by the reaction of 2-benzoxazolethiol and trichloromethyl chloroformate in benzene. The condensing agent 3 is shown to be useful for the preparation of amides, esters, and dipeptides under mild conditions. A successful polyamide synthesis by the polycondensation of isophthalic acid with diamines using 3 is also described.
