Nondestructive, colorimetric monitoring of amines and thiols on a solid support.

A new, nondestructive, highly sensitive method for colorimetric monitoring of primary amines, secondary amines, and thiols on a solid support was developed. The resin used in this method is simply regenerated for the repetition of the reaction or an ensuing reaction. By using this new method, several peptides containing secondary amide linkages and C-terminal hydrazide groups were prepared in high purities and yields.