AbstractCompound10b, 6‐acetamido‐6,8‐dideoxy‐D‐erythro‐β‐D‐galacto‐octopyranosyl‐1‐oxyacetic acid sodium salt, was synthesised by hydrazinolysis of Lincomycin, acetylation of methylthiolincosaminide (MTL)9a, and by subsequent glycosylation of acetate9bwith methyl glycolate under mild conditions (NIS/TfOH). The methyl ester10awas hydrolysed by treatment with Amberlite Ira‐4OO (OH−) resin and aqueous sodium hydroxide, followed by neutralisation with Dowex‐50 W × 8 (H+) resin and lyophilisation to give10b. This carboxylate may represent the first derivative in a novel series of sialidase inhibitors utilising carbohydrate natural products. The phosphonate11c, prepared under the same experimental conditions with dibenzyl(hydroxy‐methyl) phosphonate as acceptor, also displays an inhibitory activity towardsClostridium perfringenssialidase