214 THE CARBOHYDRATES. 



by LEDDERHOSE l from chitin by the action of concentrated hydrochloric 

 acid. Recently it has been obtained as a cleavage product of several 

 mucin substances and proteins (see pages 83 and 164) . Glucosamine is, 

 as E. FISCHER and LEUcns 2 have shown, a derivative of glucose or d- 

 mannose (probably glucose), and is a a-amino-sugar. 



The free base, which can crystallize in needles, is readily soluble in 

 water with an alkaline reaction, and quickly decomposes. The charac- 

 teristic hydrochloride forms colorless crystals which are stable in the air 

 and readily soluble in water, difficultly soluble in alcohol, and insoluble in 

 ether. The solution is dextrorotatory, (a) D = +70.15 to 74.64, at various 

 concentrations. 3 Glucosamine has a reducing action similar to that of 

 glucose, and gives the same osazone, but is not fermentable. With benzoyl- 

 chloride and caustic soda it gives a crystalline ester. In alkaline solution 

 it gives with phenylisocyanate a compound which can be converted into 

 its anhydride by acetic acid, and is used in the separation and detection 

 of glucosamine (SxEUDEL 4 ). On oxidation with nitric acid it yields 

 norisosaccharic acid, whose lead salt can be separated, and whose salts 

 with cinchonine or quinine are difficultly soluble in water and can also 

 be used very successfully in the detection of glucosamine (NEUBERG and 

 WOLFF 5 ) . On oxidation with bromine, chitaminic acid (d-glucosaminic 

 acid) is produced, and this is converted into chitaric acid, CeHioOe, 

 by nitrous acid. On treatment with nitrous acid glucosamine yields 

 a non-fermentable sugar called chitose. 



EHRLICH 6 has suggested a test which does not respond with the free glucos- 

 amine, but with the mucins and other protein bodies containing an acetylated 

 glucosamine. It consists in warming the substance, which has previously been 

 treated with alkali, with a hydrochloric-acid solution of dimethylaminobenzalde- 

 hyde, when a beautiful red color is obtained. 



Glucosamine is best prepared from decalcified lobster-shells by treat- 

 ing with hot concentrated hydrochloric acid. 7 In regard to its prepara- 

 tion from protein substances we must refer to the works cited on page 

 83, footnote 3. 



Albamine (diglucosamine), (C d H u O 4 N)a+HjO, is the name given by S. FRANKEL 8 

 to a body which he isolated from the products of the hydrolysis of ovalbumin 

 with baryta, as well as in its digestion. Albamine is amorphous, dextrogyrate, 



1 Zeitschr. f. physiol. Chem., 2 and 4. 



2 Ber. d. d. chem. Gesellsch., 36. 



3 See Hoppe-Seyler-Thierf elder's Handbuch, 8. Aufl.; Stindwik, Zeitschr. f. physiol. 

 Chem., 34. 



4 Zeitschr. f. physiol. Chem., 34. 



5 Ber. d. d. chem. Gesellsch., 34. 



6 Mediz. Woche, 1901, No. 15; see Langstein, Ergebnisse der Physiol., I, Abt. 1, 88. 



7 See Hoppe-Seyler-Thierfelder's Handbuch, 8. Aufl. 

 6 Monatsh. f . Chem., 19. 



