The Methyl Ethers of D-Galactosamine

6-dimethyl ether of n-galactosamine has been isolated from the hydrolyzate of methylated, desulfated jS-heparin.  

Methyl ethers of 2-amino-2-deoxy-D-allose have been prepared in order to be subsequently degraded into methyl ethers of n-ribose. Methylation of methyl 2-acetamido-4,6-0-benzylidene-2-deoxy-o -D-alloside gave the 3-methyl ether, which, in turn, was hydrolyzed to afford methyl 2-acetamido-2-deoxy-3-0-methyl-a-D-allopyranoside. After partial methylation, a dimethyl ether, probably the 3,6, was isolated, whereas exhaustive methylation afforded the 3,4,6-trimethyl ether. An identical trimethyl ether was isolated after methylation of methyl 2-acetamido-3,4,6-tri-0-acetyl-2-deoxy-a-n-alloside. Hydrolysis of the methyl glycosides of both the 3-methyl and the 3,4,6-trimethyl ethers gave crystalline hydrochlorides, and the base of the former ether was characterized by means of its crystalline Schiff base with 2-hydroxynaphthaldehyde. 

Walden inversion, at C3, of methyl 2-acetamido-2-deoxy-4-0-methyl-3,6-di-O-methylsulfonyl-a-D-glucoside took place on heating it with sodium acetate in 2-methoxyethanol (methyl Cellosolve) solution the product afforded, after acetylation, a sirupy methyl 2-acetamido-3,6-di-0-acetyl-2-deoxy-4-0-methyl-a-D-alloside. Removal of the 0-acetyl groups, followed by methylation, gave the same 3,4,6-trimethyl ether previously reported. 

Methylation of methyl 2-acetamido-4,6-0-benzylidene-2-deoxy-a-D-altroside, obtained by hydrolysis of the 3-acetate estergave a 3-methyl ether. Hydrolysis of the benzylidene group, and tritylation of the resulting glycoside, led to crystalline derivatives. 

In the reaction of Af-acetyl derivatives of methylated 2-amino-2-deoxy sugars with alkali, followed by condensation with the Ehrlich reagent, the amount of color obtained is found to depend upon the position of the methyl ether grouping, no coloration being observed with 4-methyl ethers. When sodium carbonate is used, the color formation is enhanced by a methyl ether at C3, whereas no difference in the color obtained is observed with the use of borate.  

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