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 malonates has been achieved by means of Mn(OAc)3-mediated oxidative coupling reaction, giving C3-modified DANA derivatives 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. Direct modification at the C-3 position of 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA) derivatives with malonates has been achieved by Mn(OAc)3-mediated oxidative coupling reaction, affording C3-modified DANA derivatives in good yield with high diastereo-selectivity. However, 3-CH2COOH-DANA, designed as a candidate sialidase inhibitor, showed weak activity, possibly because the acidic functional group is too close to the DANA skeleton.