 An amide group bonds the sugar to an n-alkane spacer, and the spacer is bonded to the dye through an ester group.Third-generation Glycoazodyes are synthesized using amino sugars such as 6-amino-6-deoxy-D-galactose or 6' amino-6'-deoxylactose.The point of the amide bond is controlled by protecting the alcohol groups on the sugar and allowing the free amine to react.