Modification of the C3-Position of 2,3-Dehydro-2-deoxy-N-acetylneuraminic Acid with An Acetic Acid Equivalent

Direct modification at the C-3 position of 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA) derivatives with mal-onates has been achieved by means of Mn(OAc)3-mediated oxidative coupling reaction, giving C3-modified DANA deriv-atives in good yield with high diastereo-selectivity. We also designed and synthesized 3-CH2COOH-DANA as a candidate sialidase inhibitor, but found that its inhibitory activity towards several sialidases was weak, possibly because the acidic functional group is located too close to the DANA skeleton.