Thioglycosiduronic Acids

Analogous reaction of (2,3,4-tri-0-acetyl-/3-D-glucopyranosyl bro-mide)uronamide with sodium ethanethioxide led208 to ethyl 2,3,4-tri-0-acetyl-l-thio-/3-D-glucopyranosiduronamide, which, on deprotection with methanolic ammonia, gave ethyl l-thio-/3-D-glucopyrano-siduronamide, also obtainable from 61 (R = Et) by treatment with methanolic ammonia. 

A patent209 on the synthesis of purin-6-yl 1-thio-D-glucopyranuron-amide and purin-6-yl 1-thio-D-glucofuranuronamide involves conden- 

Condensation of 1 in ethanol with potassium ethylxanthate gave210 the crystalline O-ethyl S-glycosyl xanthate 63 (R = Et) in high yield on treatment with cold methanolic ammonia, the compound underwent O- and S-deacetylation and 1 actonization, to give a hygroscopic product to which structure 64 has been ascribed. Treatment of 64 with diazomethane, followed by acetylation, resulted in the known201 1-thioglycoside derivative 61 (R = Me). 

Condensation of 1 in acetone with silver or potassium thiocyanate, under mild conditions, results212,213 in the formation of the corresponding 1-thiocyanic ester which, on heating, readily rearranges to the 1-isothiocyanate isomer (see Section VI). 

D-Glucuronic acid215 and its 6,3-lactone216 combine readily with two equivalents of a thiol in the presence of hydrochloric acid (conditions of mercaptolysis) to give the dithioacetal (66) of the aldehydo form of the lactone. Compound 66 opens in sodium hydroxide216 or ammo- 

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Only a few 1-thioglycosiduronic acids have been encountered in biological material as metabolites of thiols or of compounds transformed... 

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