A-D-Glucopyranosyl azide

S. 2,3,4-Trl-0-benzyl-6-0-f-butyldimethylsilyl-a-D-glucopyranosyi-(1-+6)-2,3,4-trl-0-benzoyl-0-D-glucopyranosyl-(1>6)-2,3,4-tri-O-benzyi-a-D-glucopyranosyl Azide (18)... 

A solution of 2,3,4-tri-O-benzyl-a-D-glucopyranosyl azide 16 (21 mg, 0.044 mmol) in 0.6 mL of dichloromethane was stirred in the presence of powdered 4-A molecular sieves and 24 mg (0.067 mmol) of Cu(OTf)2. After 10 min, a solution of 100 mg (0.067 mmol) of 3-methoxy-2-pyridyl 2,3,4-tri-O-benzyl-6-0-r-butyldimethylsilyl-a-D-glucopyranosyl-(1—>6)-2,3,4-tri-0-benzoyl-0-D-glucopyranoside 10 in 1.6 mL of dichloromethane was added dropwise over 5 h. A few drops of pyridine were added, the solvent was evaporated, and the residue was chromatographed with CCl4-acetone (10 1) as eluant to give the title compound (44 mg, 66%). 

Tri-O-benzyl-a-D-glucopyranosyl azide 2,3,4,6-Tetra-0-benzyl-a-D-glucopyranosyl-(l->6)-2,3,4-tri-0-benzoyl-p-D-glucopyranosyl-(l—>6)-2,3,4-tri-0-benzyl-a-D-glucopyranosyl azide... 

Tri-O-acetyl-a-D-glucopyranosyl azide (189), obtained from Brigl s chloride (3,4,6-tri-(9-acetyl-2-trichloroacetyl-p-D-glucopyranosyl chloride) by selective removal of the trichloroacetyl group has long been the only representative of this class of compounds. 

By this method in HMPA, a 1,2-cis azidouronic acid derivative was prepared. The yield of methyl (2,3,4-tri-O-acetyl-a-D-glucopyranosyl azide)uron-ate (196) was 56% starting with the (3-chloride 195, and its further transformation into the corresponding acid 197 was also described. ... 

Tri-(9-acetyl-2-(9-methyl-a-D-gluco- (198) and -galactopyranosyl azide (199) are formed from the corresponding peracetates with trimethylsilyl azide under catalysis by SnCU, 2,3,4,6-Tetra-O-benzyl-a-D-glucopyranosyl azide has been obtained in two different ways. With other ether substituents, as for example in the formation of 2,3,4,6-tetra-0-(5-phthalimido-3-oxapentyl)-D-glucopyranosyl azide, no a-selectivity could be observed. ... 

Tetra-O-benzyl-a-D-glucopyranosyl azide was obtained by nucleophilic displacement reaction of the corresponding a-glucosyl phosphate with azide ion under phase-transfer catalysis conditions. Oxidation of unprotected D-glycopyranosyl azides (with NaOQ, NaHCOj, catalytic TEMPO, H2O) afforded the corresponding D-glycopyraniuronosyl azides, which were isolated as the O-acetylated methyl ester derivatives in good yields. ... 

Treatment of a-D-glucopyranosyl azide with triphenylphosphine in the presence of carbon dioxide afforded carbamates 26 and 27, in which the configuradon at C-3 is retained and inverted, respecdvely, as well as their a-D-fioanose isomers. Similar results were observed for a-D-xylopyranosyl azide, and a mechanism involving intramolecular displacement at C-3 was invoked to explain the inverted products. ... 

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