Primary amines can be protected by conversion to 2,5-dimethylpyrroles, from which they can be released by reaction with hydroxylamine hydrochloride: J. Chem. Soc., Perkin 1, 2801 (1984). The method has been found useful for protecting amino sugars in oligosaccharide synthesis: J. Org. Chem., 63, 4570 (1998), and also in the protection of an arylamine during Cu(I) promoted methoxylation of a ring bromo or iodo substituent; Synthesis, 1599 (1998).