Glycosyl Bunte Salts: A Class of Intermediates for Sugar Chemistry.
S-Glycosyl thiosulfates have been discovered as a new class of synthetic intermediates in sugar chemistry, named "glycosyl Bunte salts" after 19th-century German chemist, Hans Bunte. The synthesis was achieved by direct condensation of unprotected sugars and sodium thiosulfate using a formamidine-type dehydrating agent in water-acetonitrile mixed solvent. The application of glycosyl Bunte salts is demonstrated with transformation reactions into other glycosyl compounds such as a 1-thio sugar, a glycosyl disulfide, a 1,6-anhydro sugar, and an O-glycoside.
One-pot synthesis of glycosyl phenylthiosulfonates from sulfinate, S and glycosyl bromides.
Glycosyl phenylthiosulfonates are reagents which are valuable for the S-glycosylation decoration of organic compounds and proteins. Here, one-pot multiple-component synthesis of glycosyl phenylthiosulfonates from sulfinate, sulfur powder and glycosyl bromides is reported. The reactions afford glycosyl phenylthiosulfonates in good yields under mild conditions. Further application and exploration of glycosyl phenylthiosulfonates are still on underway in our group.
Synthèse de disaccharides à liaison (1→4) posseédant un résidu réducteur 2-acétamido-2-désoxy-D-glucopyranose: emploi de dérivés du 2-acétamido-1,6-anhydro-2-désoxy-β-D-glucopyranose☆
Abstract Ammonium hydroxide treatment of 1,6:2,3-dianhydro-4- O -benzyl-β- D -mannopyranose, followed by acetylation, gave 2-acetamido-3- O -acetyl-1,6-anhydro-4- O -benzyl-2-deoxy-β- D -glucopyranose which was catalytically reduced to give 2-acetamido-3- O -acetyl-1,6-anhydro-2-deoxy-β- D -glucopyranose ( 6 ), the starting material for the synthesis of (1→4)-linked disaccharides bearing a 2-acetamido-2-deoxy- D -glucopyranose reducing residue. Selective benzylation of 2-acetamido-1,6-anhydro-2-deoxy-β- D -glucopyranose gave a mixture of the 3,4-di- O -benzyl derivative and the two mono- O -benzyl derivatives, the 4- O -benzyl being preponderant. The latter derivative was acetylated, to give a compound identical with that just described. For the purpose of comparison, 2-acetamido-4- O -acetyl-1,6-anhydro-2-deoxy-β- D -glucopyranose has been prepared by selective acetylation of 2-acetamido-1,6-anhydro-2-deoxy-β- D -glucopyranose. Condensation between 2,3,4,6-tetra- O -acetyl-α- D -glucopyranosyl bromide and 6 gave, after acetolysis of the anhydro ring, the peracetylated derivative ( 17 ) of 2-acetamido-2-deoxy-4- O -β- D -glucopyranosyl-α- D -glucopyranose. A condensation of 6 with 3,4,6-tri- O -acetyl-2-deoxy-2-diphenoxyphosphorylamino-α- D -glucopyranosyl bromide likewise gave, after catalytic hydrogenation, acetylation, and acetolysis, the peracylated derivative ( 21 ) of di- N -acetylchitobiose.