Bifunctional catalyst for a wide variety of acylation reactions. See, for example: J. Chem. Soc. (C), 89 (1969). For use of 2-pyridyl esters as active esters in peptide coupling, see: J. Chem. Soc.(C), 2896 (1971); Chem. Ber., 118, 468 (1985). The group can be introduced on to the N-protected peptide using DCC in pyridine, and is displaced by the amino-residue under mild conditions. For peptide reagents. Similar methodology has also been used in an improved preparation of trichloroethyl esters: Synthesis, 24 (1979). Reacts with SOCl2 to form di-2-pyridyl sulfite, a useful reagent for in situ formation of N-sulfinylamines, nitriles, isocyanides and carbodiimides under mild conditions: Tetrahedron Lett., 27, 1925 (1986).
