Chemistry of N-acetylneuraminic acid (Neu5Ac)

Sialic acid (Neu5Ac, Neu5Gc, KDN) is a compound with the most complicated molecule structure of the monosaccharides. Although sialic acid is a small molecule of about molecular weight 3 10, it consists of so many functional groups. Moreover, those functional groups take the equilibrium state peculiar to sugar according to conditions. When undertaking the synthetic chemistry of sialic acid for the first time, it makes it a little difficult. The experiential conditions in each reaction becomes very important in order to synthesize the desired compound, because sialic acid has the property of being highly sensitive to reacting with various reagents. This minireview, introduces a peculiar reaction and the fundamental reaction of Neu5Ac from among many which have already been reported. The chemical diversity of most typical N-acetylneuraminic acid in sialic acid is also described from each action by several simple reactions.