In this thesis, new methods for the synthesis of several different types of glyco-conjugates were developed. The target including natural glyco-conjugated ligand, drug mimetic and derivatives. 2,5-neuraminic acid was chosen as the first target. This glycol-conjugate was a very important signal transductor during fertilization of the sea urchin. Here, an amide bond formation reaction was used to construct the 2,5-neuraminic acid dimer. By this method, glycosidic bond was formed through an exclusive