Polymer-bound mixed carboxylic anhdrides as a stable form of activated carboxylic acids

Abstract

Polymer-bound mixed carboxylic anhydrides can be prepared under mild conditions by the condensation of carboxylic acids (including N-protected amino acids) with polymer-bound acid chlorides. These mixed anhydrides function as polymeric reagents in the sense that they will react readily with monomeric nucleophiles such as amines to form amide or peptide products, depending on the identities of the mixed anhydride and amine reactants. However, in spite of their reactivity, these polymeric mixed anhydrides exhibit a significant degree of stability under conditions of prolonged storage, which suggests that such compounds have commercial utility as a relatively stable form of highly activated carboxylic acids. The polymeric support can be reactivated and recycled for repeated use in the derivatization process.

Dependencies are inferred from the claim text.