Convenient method of peptide hydrazide synthesis using a new hydrazone resin

Peptide hydrazides can be easily synthesized using a new hydrazone resin, obtained via acylation of aminomethyl polystyrene by Fmoc-hydrazone of pyruvic acid. It was shown that the hydrazone linker is completely stable in the course of standard Fmoc SPPS. Moreover, it can tolerate a treatment with 5% TFA/DCM thus permitting selective removal of Mtt or related acid-labile protecting groups. Subsequent application of cleavage cocktails containing net TFA permits to obtain the desired peptides in a reasonable yields and purity. Synthesized peptide hydrazides can be applied as building blocks for the conjugation with different carrier molecules using hydrazone ligation technique.