Crystallise the hydrochloride from 3M HCl, water, and finally water/EtOH/acetone as for galactosamine hydrochloride. [Purchase & Braun Org Synth 26 36 1946, Stacey & Webber Methods in Carbohydrate Chemistry I 228 1962, Academic Press.] The salt has also been purified by dissolving in the minimum volume of boiling H2O (charcoal), filtering and adding a large excess of 95% EtOH (~4 volumes) and stirring vigorously for several hours. Collect the crystals after 4-6hours to give anomer which mutarotates ] D +100o to +72o (equilibrium, c 1, H2O). A large amount of the -anomer stays in solution. This can be precipitated from the filtrate by adding excess Et2O. The mixture of -plus -anomers has  D +68.8o (c 4.75, H2O, mutarotating to +70.1o)[Leaback Biochemical Preparations 10 118 1963]. Note that if Et2NH is used instead of Et3N, conversion to the -anomer can be complete (see above). [Stacey et al. Methods in Carbohydrate Chemistry I 3061962, Academic Press; Beilstein 4 IV 2018.]
Novel application of glucosamine to prepare medical agent for treating vertigo. Found in chitin, in mucoproteins, and in mucopolysaccharides. Antiarthritic. Recent studies show that its chondroprotective activity is related to its antiapoptic properties.