Publisher Summary This chapter discusses the methyl ethers of 2-amino-2-deoxy sugars. Interest in the preparation of methylated derivatives of 2-amino-2-deoxy sugars, especially of u-glucosamine (2-amino-2-deoxy-D-glucose) and D-galactosamine (2-amino-2-deoxy-D-galactose) arose from the desire to apply the methylation procedure of structural determination to oligo- and poly-saccharides containing aminodeoxy sugars. The methods of synthesis of methylated derikatives of amino sugars are, in general, the same as those used for the preparation of methylated derivatives of other monosaccharides. The solubility of the starting material has governed the choice of the methylating agent, and has prompted some modifications of the classical procedures; for example, the use of dimethyl sulfate plus sodium hydroxide in dioxane solution, and of methyl iodide plus silver oxide in N , N -dimethylformamide. Most syntheses in the D-glucosamine and D-galactosamine series, using glycosides, have been carried out with α anomers. The preparation of these derivatives is simple, requiring only N -acetylation or total acetylation of the amino sugar hydrochlorides followed by glycosidation, whereas formation of the β anomers requires the preparation of the unstable O - acetylglycosyl halides as intermediates. Although, in the D-glucosamine series, the resulting methyl 2-acetamido-2-deoxy-α-D-glucopyranosidies always contaminated by approximately 20% of its β anomer, it is easily purified through its 3,4,6-tri- O -acetyl, 4,6- O -benzylidene, or 6- O -triphenylmethyl (6-0-trityl) derivatives.