Polymer esters anchoring groups

In connection with different kinds of anchoring groups we should recall that numerous biologically active peptides have a carboxamide rather than a free carboxyl at their C-termini. As mentioned earlier, such peptide amides can be obtained by ammonolysis of the ester bond between peptide and polymer. A second possibility, to wit, acidolysis is equally useful and often practiced. In 1970 Pieta and Marshall constructed a new polymeric support in which the acid labile N—C bond in benzhydrylamine serves as the point of cleavage (Fig. 7). Of course, the bond s sensitivity to acids can be further increased by electron-releasing substituents such as methoxy groups. 

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