 Neuraminic acid

Neuraminic acid (5-amino-3,5-dideoxy-D-"glycero"-D-"galacto"-non-2-ulosonic acid) is an acidic amino sugar with a backbone formed by nine carbon atoms.Although 9-carbon sugars do not occur naturally, neuraminic acid may be regarded as a theoretical 9-carbon ketose in which the first link of the chain (the –CH2OH at position 1) is oxidised into a carboxyl group (–C(=O)OH), the hydroxyl group at position 3 is deoxidised (oxygen is removed from it), and the hydroxyl group at position 5 is substituted with an amino group (–NH2).