reported in 2015. These Glycoazodyes use an amido-ester linker. An amide group bonds the sugar to an n-alkane spacer, and the spacer is bonded to the dye through an ester group. Synthesis 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. The point of the ester group is controlled by choosing a azo dye with a different alcohol group position. Either the dye or the sugar is reacted with succinic anhydride. This forms an amide group with the sugar or an ester group with the dye. The free carboxylic acid may then react with the alcohol group or amine group on the corresponding dye or sugar. The condensation product is then deprotected. Properties A variety of fabrics such as wool, silk, nylon, polyester, polyacrylic, polyacetate, and polyurethane may be dyed with Glycoazodyes under moderate temperatures and pressures in aqueous solutions. First-generation Glycoazodyes dye cotton poorly. However, second-generation Glycoazodyes dye cotton effectively. Wool dyed with Glycoazodyes shows good fastness when exposed to the ISO 105-C06 washing and ISO 105 X12 rubbing tests. Glycoazodyes vary in their water solubility. They may be soluble in cold to warm water and may dissolve after stirring or upon addition. Minor variations in absorption spectra occur when Glycoazodye solutions are prepared, using water, acetone, or methanol solvents. Converting a parent azo dye to a Glycoazodye may produce a small hypsochromic shift in the absorption spectra. Environmental impact Several properties may make Glycoazodyes an environmentally friendly alternative to traditional synthetic dyes. The increased hydrophilicity of Glycoazodyes allows for the elimination of surfactants, mordants, and salts, during the dyeing process and permits the aqueous dying of a variety of textiles at moderate temperatures and pressures. The unique structure may also allow for the treatment of textile effluent through biological means. Fusarium oxysporum efficiently decolourizes the first-generation Glycoazodye 4-{N,N-Bis[2-(D-galactopyranos-6-yloxy)ethyl]-amino}azobenzene. Various other Ascomycota fungi show a similar potential to decolourise Glycoazodyes, but to a lesser extent. Detoxification has been measured, using the Daphnia magna acute toxicity test, showing a 92% dye detoxification after 6 days. This detoxification method produces low concentrations of nitrobenzene, aniline, and nitrosobenzene. External links http://onlinelibrary.wiley.com/doi/10.1002/ejoc.200600686/abstract References Dyes Azo compounds Organic pigments Carbohydrate chemistry Carbohydrates