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Guanidination of a peptide side chain amino group on a solid support.

A novel guanidination method of converting a peptide side chain amino group to a guanidino group on a solid support is described. Four guanidinating reagents were evaluated using a model tetrapeptide attached to a polystyrene resin. Experimental data indicate that the two nitroguanidinating reagents, but not the two tosylguanidinating reagents, can be used effectively in solid phase peptide synthesis.