Studies on dextranases. 3. Insolubilization of a bacterial dextranase

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.     

Studies related to the synthesis of derivatives of 2,6-diamino-2,3,4,6-tetradeoxy-D-erythro-hexose (purpurosamine C), a component of gentamicin C12

Reduction of 1,6-anhydro-3,4-dideoxy-β-D-glycero-hex-3-enopyranos-2-ulose (levoglucosenone) with lithium aluminium hydride afforded principally 1,6-anhydro-3,4-dideoxy-β-D-threo-hex-3-enopyranose (3), which was converted into 3,4-dihydro-2(S)-hydroxymethyl-2H-pyran (8) following acid-catalysed methanolysis and reductive rearrangement of the resulting α-glycoside 4 with lithium aluminium hydride. 1,6-Anhydro-3,4-dideoxy-2-O-toluene-p-sulphonyl-β-D-threo-hexopyranose, prepared from 3, reacted slowly with sodium azide in hot dimethyl sulphoxide to give 1,6-anhydro-2-azido-2,3,4-trideoxy-β-D-erythro-hexopyranose, which was transformed into a mixture of methyl 2-acetamido-6-O-acetyl-2,3,4-trideoxy-α-D-erythro-hexopyranoside (10) and the corresponding β anomer following acid-catalysed methanolysis, catalytic reduction, and acetylation. Acid treatment of methyl 4,6-O-benzylidene-3-deoxy-α-D-erythro-hexopyranosid-2-ulose yielded the enone 15, which was readily transformed into methyl 6-O-acetyl-3,4-dideoxy-α-D-glycero-hexopyranosid-2-ulose (19). Procedures for the conversions of DL-8, 10, and 19 into methyl 2,6-diacetamido-2,3,4,6-tetradeoxy-α-D-erythro-hexopyranoside (methyl N,N′-di-acetyl-α-purpurosaminide C) have already been described.     

The deamination of methyl 5-amino-5,6-dideoxy-2,3-O-isopropylidene-α-L-talo- and -β-D-allo-furanoside with nitrous acid

Deamination of methyl 5-amino-5,6-dideoxy-2,3-O-isopropylidene-α-L-talofuranoside (6) with sodium nitrite in 90% acetic acid at ≈0° gave methyl 6-deoxy-2,3-O-isopropylidene-α-L-talofuranoside (8a) and methyl 6-deoxy-2,3-O-isopropylidene-β-D-allofuranoside (9a) (combined yield, 12.3%), the corresponding 5-acetates 8b (2.9%) and 9b (26.4%), and the unsaturated sugar methyl 5,6-dideoxy-2,3-O-isopropylidene-β-D-ribo-hex-5-enofuranoside (10) (43.5%). Similar deamination of methyl 5-amino-5,6-dideoxy-2,3-O-isopropylidene-β-D-allofuranoside (7) gave 8a and 9a (combined yield, 20.4%), 8b (12.5%), 9b (25.8%), 10 (7.7%), and the rearranged products 6-deoxy-2,3-O-isopropylidene-5-O-methyl-L-talofuranose (13a, 17.5%) and the corresponding 1-acetate 13b (14.1%). A synthesis of 13a was accomplished by successive methylation and debenzylation of the conveniently prepared benzyl 6-deoxy-2,3-O-isopropylidene-α-L-talofuranoside (15b). Differences between the two sets of deamination products can be rationalized by assuming that the carbonium-ion intermediate reacts in the initial conformation assumed, before significant interconversion to other conformations occurs.     

A short synthesis of 4-deoxy-4-fluoroglucosaminides: Methylumbelliferyl N-acetyl-4-deoxy-4-fluoro-β-D-glucosaminide

A convenient method of synthesis of 1,6-anhydro-4-deoxy-2-O-tosyl-4-fluoro-β-D-glucopyranose by fusion of 1,6;3,4-dianhydro-2-O-tosyl-β-D-galactopyranose with 2,4,6-trimethylpyridinium fluoride was found. By a successive action of ammonia, methyl trifluoroacetate, and acetic anhydride, the resulting compound was transformed into 1,6-anhydro-3-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-β-D-glucopyranose, which was converted into 3,6-di-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-αD-glucopyranosyl fluoride by the reaction with HF/Py. The resulting fluoride was further used as a glycosyl donor in the synthesis of methylumbelliferyl N-acetyl-4-deoxy-4-fluoro-β-D-glucosaminide.     

Selective esterification of 1,6-anhydrohexopyranoses: The possible role of intramolecular hydrogen-bonding

Selective esterification reactions of 1,6-anhydro-3-deoxy-β-D-xylo-hexopyranose(1), 1,6-anhydro-β-D-glucopyranose (7), and several derivatives of 7, were conducted with an acid chloride or acid anhydride in pyridine. Reaction of 1 with p-toluenesulfonyl chloride and with benzoyl chloride gave 70 and 63%, respectively, of the 2-esters. The 2-methyl and 2-benzyl ethers of 7, both having strongly hydrogen-bonded C-4 hydroxyl group, reacted with p-toluenesulfonyl chloride to yield the 4-monosulfonates (71 and 74%, respectively). Esterification of the 2-methyl ether and 2-p-toluenesulfonate of 7 with p-toluenesulfonic anhydride instead of with p-toluenesulfonyl chloride led to increased yields of the 4-p-toluenesulfonates after a shorter reaction-time.     

Acid-catalyzed pyrolytic synthesis and decomposition of 1,4:3,6-dianhydro-α-d-glucopyranose

1,4:3,6-dianhydro-α-d-glucopyranose (1) was formed, together with 1,6-anhydro-3,4-dideoxy-β-d-glycero-hex-3-enopyranos-2-ulose (levoglycosenone, 2) and levoglucosan (4), on acid-catalyzed pyrolysis of d-glucose, amylopectin, and cellulose. Pyrolysis of 1 in the presence of acid provided significant quantities of 2, indicating that 1 can act as a pyrolytic precursor of 2. A pyrolysis product from cellulose previously considered to be 1,6-anhydro-3-deoxy-β-d-erythro-hex-3-enopyranose (12) was shown to be dianhydride 1.     

Synthesis of Acetyl Derivatives of 2-Amino-2-deoxy-1,6-dithio-D-glucose

From 2-anisylideneamino-1,3,4-tri-O-acetyl-2,6-dideoxy-6-S-acetyl-6-thio-β-D-glucopyranose, three derivatives of 2-amino-2-deoxy-1,6-dithio-D-glucose were prepared, i.e., 2-anisylidene-amino-3,4-di-O-acetyl-1,2,6-trideoxy-1,6-di-S-acetyl-1,6-dithio-β-D-glucopyranose, 2-amino-3,4-di-O-acetyl-1,2,6-trideoxy-1,6-di-S-acetyl-1, 6-dithio-β-D-glucopyranose hydrochloride and 2-acet-amido-3,4-di-O-acetyl-1,2,6-trideoxy-1-mercapto-6-S-acetyl-6-thio-β-D-glucopyranose; and some of their properties were described.     

Ring-opening reactions of sucrose epoxides: Synthesis of 4′-derivatives of sucrose

The 2,1′-O-isopropylidene derivative (1) of 3-O-acetyl-4,6-O-isopropylidene-α-d-glucopyranosyl 6-O-acetyl-3,4-anhydro-β-d-lyxo-hexulofuranoside and 2,3,4-tri-O-acetyl-6-O-trityl-α-d-glucopyranosyl 3,4-anhydro-1,6-di-O-trityl-β-d-lyxo-hexulofuranoside have been synthesised and 1 has been converted into 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-d-lyxo-hexulofuranoside (2). The S_N2 reactions of 2 with azide and chloride nucleophiles gave the corresponding 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,3,6-tri-O-acetyl-4-azido-4-deoxy-β-d-fructofuranoside (6) and 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,3,6-tri-O-acetyl-4-chloro-4-deoxy-β-d-fructofuranoside (8), respectively. The azide 6 was catalytically hydrogenated and the resulting amine was isolated as 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 4-acetamido-1,3,6-tri-O-acetyl-4-deoxy-β-d-fructofuranoside. Treatment of 5 with hydrogen bromide in glacial acetic acid followed by conventional acetylation gave 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,3,6-tri-O-acetyl-4-bromo-4-deoxy-β-d-fructofuranoside. Similar S_N2 reactions with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-d-ribo-hexulofuranoside (12) resulted in a number of 4′-derivatives of α-d-glucopyranosyl β-d-sorbofuranoside. The regiospecific nucleophilic substitution at position 4′ in 2 and 12 has been explained on the basis of steric and polar factors.     

Synthesis of a C-nucleoside analog of the antibiotic cordycepin

A C-nucleoside analog of cordycepin, 6-amino-8-(3-deoxy-β-D-erythro-pentofuranosyl)purine (6), has been synthesized. 3-Deoxy-2,5-di-O-(p-nitrobenzoyl)- β-D-erythro-pentofuranosyl bromide reacted with mercuric cyanide in nitromethane to give 2,5-anhydro-4-deoxy-3,6-di-O-(p-nitrobenzoyl)-D-ribo-hexononitrile which, after acid hydrolysis and removal of the protecting groups, afforded 2,5-anhydro-4-deoxy-D-ribo-hexonic acid. Reaction of this acid with 4,5,6-triaminopyrimidine gave the corresponding amide, which was pyrolyzed to give compound 6. The mass- and n.m.r.-spectral data for the synthesized analog are quite similar to those of the natural antibiotic.     

Stereoselective hydrogenation of methyl dideoxy- and trideoxy-β-D-hex-5-enopyranosides

Hydrogenation, severally, of methyl 3-azido-2,3,6-trideoxy-β-D-erythro-hex-5-enopyranoside, its 3-benzamido analogue, and methyl 2,6-dideoxy-β-D-threo-hex-5-enopyranoside in the presence of palladium-on-barium sulphate gave the corresponding 6-deoxy-β-D-hexopyranoside derivatives. Stereoselective addition of hydrogen was observed in each case. Methyl 2,6-dideoxy-β-D-arabino-hexopyranoside was also prepared by reductive dehalogenation of methyl 3,4-di-O-benzoyl-6-bromo-2,6-dideoxy-β-D-arabino-hexopyranoside.     

Synthesis of D-ristosamine and its derivatives

A convenient preparative route involving eleven steps starting from D-glucose is described for the synthesis of D-ristosamine (15) hydrochloride. Methyl 2-deoxy-β-D-arabino-hexopyranoside, prepared from 3,4,6-tri-O-acetyl-1,5-anhydro-2-deoxy-D-arabino-hex- 1-enitol, was benzylidenated, and the product mesylated to give methyl 4,6-O-benzylidene-2-deoxy-3-O-methylsulfonyl-β-D-arabino-hexopyranoside. Azidolysis of this compound and subsequent opening of the 1,3-dioxane ring with N-bromosuccinimide gave methyl 3-azido-4-O-benzoyl-6-bromo-2,3,6-trideoxy-βD-ribo-hexopyranoside. Simultaneous reduction of the azido and bromo groups gave a mixture that was benzoylated to give methyl N,O-dibenzoyl-β-D-ristosaminide and then hydrolyzed to 15 hydrochloride (3-amino-2,3,6-trideoxy-D-ribo-hexopyranose hydrochloride).     

Solvent effects on the photochemical addition of acetone to 3,4,6-tri-O-acetyl-D-glucal

Irradiation of a solution of 3,4,6-tri-O-acetyl-D-glucal (1) in various mixtures of acetone (2) and isopropyl alcohol was investigated to elucidate solvent effects on the photochemical addition of 2 to 1. At high concentrations of acetone (2), 5,6,8-tri-O-acetyl-2,4:3,7-dianhydro-1-deoxy-2-C-methyl-D-glycero-D-ido-octitol (3) was obtained selectively. In mixtures containing less than 50% (v/v) of 2, irradiation gave mainly 5,6,8-tri-O-acetyl-3,7-anhydro-1,4-dideoxy-2-C-methyl-D-gluco-octitol (4). The effects of ethanol and other solvents were examined and the mechanism of the reaction is discussed.     

Nucleosides LXXXIII. Synthetic studies on nucleoside antibiotics. 11. Synthesis of methyl 4-amino-3,4-dideoxy-β-D-ribo-hexopyranoside and -hexopyranosiduronic acid (derivatives related to the carbohydrate moiety of gougerotin)

Methyl 4-amino-3,4-dideoxy-β-D-ribo-hexopyranoside (17) and its uronic acid (19) were synthesized via a series of reactions starting from 1,2:5,6-di-O-isopropylidene-3-O-tosyl-α-D-glucofuranose. A method suitable for the large scale preparation of 3,4-dideoxy- 1,2:5,6-di-O-isopropylidene-α-D-erythro-hex-3-enofuranose(2) was devised.     

The stereochemistry of palladium- and platinum-catalyzed hydrogenations of nitro sugar epoxides

The catalytic hydrogenation of carbohydrate α-nitroepoxides with palladium and platinum was investigated with regard to regiospecificity and stereochemistry of ring opening, and the fate of the nitro group. 5,6-Anhydro-1,2-O-isopropylidene- 6-C-nitro-α-D-glucofuranose gave 6-amino-6-deoxy-1,2-O-isopropylidene-α-D-gluco-furanose under platinum catalysis. The methyl 2,3-anhydro-4,6-O-benzylidene-3-C- nitrohexopyranosides having the β-D-gulo (4), ?-D-allo (9), α-D-manno (13), and β-D-manno (18) configurations underwent facile, hydrogenolytic ring-opening in the presence of palladium, to give, regardless of the orientation of the oxirane ring, methyl 4,6-O-benzylidene-3-deoxy-3-C-nitro-D-hexopyranosides having an equatorial nitro group (5, 10, 14, and 19, respectively). In addition, 3-deoxy-3-oximino derivatives arose in various proportions, and two of these (from 9, and from 18) were isolated crystalline. It was shown that the oximes did not result from over-hydrogenation of the 3-deoxy-3-C-nitro glycosides produced, and it is suggested that they originated from intermediary nitronic acids. By catalysis with platinum, the oxirane rings in 4, 9, 13, and 18 were opened in the same regiospecific sense as with palladium, but notable differences were observed otherwise. Compound 4 gave the amino analog of 5, whereas 9 retained the nitro group and gave the 4,6-O-(cyclohexylmethylene) analog of 10. The α-D-manno epoxide 13 reacted with concomitant debenzylidenation, to yield methyl 3-amino-3-deoxy-α-D-altropyranoside hydrochloride, whereas the β-D-manno epoxide 18 gave the corresponding, debenzylidenated amino β-D-altroside together with the 4,6-O-(cyclohexylmethylene)-3-nitro- and -3-amino-β-D-mannosides. The results are compared with literature reports on the stereochemistry of hydrogenolysis of oxiranes, and mechanisms that may operate for the nitro derivatives are discussed.     

Enamine and pyrrole formation from 2-amino-2-deoxy-D-glucose and dimethyl acetylenedicarboxylate

Addition of 2-amino-2-deoxy-β-D-glucopyranose to dimethyl acetylenedicarboxylate afforded an almost quantitative yield of amorphous 2-deoxy-2-(1,2-dimethoxycarbonylvinyl)amino-D-glucose (5). Acetylation of this adduct gave crystalline 1,3,4,6-tetra-O-acetyl-2-deoxy-2-[(Z)-1,2-dimethoxycarbonylvinyl]amino-α-D-glucopyranose (6a); the corresponding β-D anomer (6b) was obtained by addition of 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-β-Dglucopyranose to dimethyl acetylenedicarboxylate. O-Deacetylation of tetra-acetate 6a with barium methoxide in methanol occurred selectively at C-1, yielding enamine 6c derived from 3,4,6-tri-O-acetyl-2-amino-2-deoxy-α-D-glucopyranose. Conversion of the crude adduct 5 into 3-methoxycarbonyl-5-(D-arabino-tetrahydroxybutyl)-2-pyrrolecarboxylic acid (7) took place by heating in water or in slightly basic media in yields up to 83%. Acetylation of 7 gave the tricyclic derivative 8, and its periodate oxidation afforded 5-formyl-3-methoxycarbonyl-2-pyrrolecarboxylic acid (9). Oxidation of 9 with alkaline silver oxide yielded 3-methoxy-carbonyl-2,5-pyrroledicarboxylic acid (10).     

Synthetic approaches to 6-substituted 9-(3-azido-3,4-dideoxy-β-d,l-erythro-pentopyranosyl)purines

Methyl 3-azido-2-O-benzoyl-3,4-dideoxy-β-dl-erythro-pentopyranoside (6) was synthesized through two routes in five steps from methyl 2,3-anhydro-4-deoxy-β-dl-erythro-pentopyranoside (1). The first route proceeded via selective azide displacement of the 3-tosyloxy group of methyl 4-deoxy-2,3-di-O-tosyl-α-dl-threo-pentopyranoside, followed by detosylation and benzoylation. The second route consisted, with a better overall yield, in the azide displacement of the mesyloxy group of methyl O-benzoyl-4-deoxy-3-O-methylsulfonyl-α-dl-threo-pentopyranoside (10), obtained by benzylate opening of 1, followed by benzoylation, debenzylation, and mesylation. Compound 6 was transformed into its glycosyl chloride, further treated by 6-chloropurine to give the nucleoside 9-(3-azido-2-O-benzoyl-3,4-dideoxy-β-dl-erythro-pentopyranosyl)-6-chloropurine (13). When treated with propanolic ammonia, 13 yielded 9-(3-azido-3,4-dideoxy-β-dl-erythro-pentopyranosyl)adenine.     

Syntheses of 2-acetamido-2-deoxy-4-O-α-D-glucopyranosyl-α-d-glucopyranose (n-acetylmaltosamine) and 2-acetamido-2-deoxy-4-O-β-d-glucopyranosyl-α-d-glucopyranose

Condensation of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside with 2,3,4,6-tetra-O-benzyl-1-O-(N-methyl)acetimidoyl-β-D-glucopyranose gave benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl)-α-D-glucopyranoside which was catalytically hydrogenolysed to crystalline 2-acetamido-2-deoxy-4-O-α-D-glucopyranosyl-α-D-glucopyranose (N-acetylmaltosamine). In an alternative route, the aforementioned imidate was condensed with 2-acetamido-3-O-acetyl-1,6-anhydro-2-deoxy-β-D-glucopyranose, and the resulting disaccharide was catalytically hydrogenolysed, acetylated, and acetolysed to give 2-acetamido-1,3,6-tri-O-acetyl-2-deoxy-4-O-(2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl)-α-D-glucopyranose Deacetylation gave N-acetylmaltosamine. The synthesis of 2-acetamido-2-deoxy-4-O-β-D-glucopyranosyl-α-D-glucopyranose involved condensation of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide in the presence of mercuric bromide, followed by deacetylation and catalytic hydrogenolysis of the condensation product.     

A facile synthesis of nucleoside derivatives of 1,4-oxathiane

Adenosine-5′-carboxaldehyde (1a) was treated with nitromethane under alkaline conditions, to give the two stereoisomeric 5′-C-(nitromethyl) derivatives (2 and 3) of adenosine. Catalytic hydrogenation of 2 gave 9-(6-amino-6-deoxy-β-D-allofuranosyl)adenine (4), which, on treatment with nitrous acid, yielded 9-(β-D-allofuranosyl)hypoxanthine (6). Similar treatment of 3 gave the α-L-talo nucleosides 5 and 7. Reaction of 2′,3′-O-p-anisylidene adenosine-5′-carboxaldehyde (1b) with ethoxycarbonylmethylene-triphenylphosphorane afforded 9-(ethyl 5,6-dideoxy-β-D- ribo-hept-5-enofuranosyluronate)adenine (8), which was hydrolyzed to the corresponding uronic acid (9). Catalytic hydrogenation of 8 gave 9-(ethyl 5,6-dideoxy-β-D-ribo-heptofuranosyluronate)adenine (10). Reduction of 8 with lithium aluminum hydride yielded two new analogs of adenosine: 9-(5,6-dideoxy-β-D-ribo-heptofuranosyl)adenine (12) and 9-(5,6-dideoxy-β-D-ribo-hept-5-enofuranosyl)adenine (13).     

Umlagerungsreaktionen bei der einwirkung von trifluormethansulfonsäure auf 2,3,4-tri-O-acetyl-1,6-anhydro-β-D-talopyranose-und 2,3,4-tri-O-acetyl-1,6-anhydro-β-D-glucopyranose

2,3,4-Tri-O-acetyl-1,6-anhydro-,β-D-talopyranose gave, in the presence of trifluoromethanesulfonic acid, the two talo ions 7 and 8, which are formed in approximately equal amounts. The hydrolytic ring-opening of the two ions proceeds stereoselectively. From 7 was formed 2,3-di-O-acetyl-1,6-anhydro-β-D-talopyranose and from 8 3,4-di-O-acetyl-1,6-anhydro-β-D-talopyranose, both having an axial, acetoxyl group. The talo ion 9 can undergo ring-contraction to the 1,6-anhydrotalofuranose ion 2. The doubly ring-contracted 1,5-anhydrotalofuranose ion 3, which can arise from 2 and 8, was also formed, and afforded the tri-O-acetyl derivatives of the furanose compounds 5 and 11. The mechanism of the ring-contraction reactions is discussed. 2,3,4-Tri-O-acetyl-1,6-anhydro-β-D-glucopyranose gave preferentially with trifluoromethanesulfonic acid and antimony pentachloride the manno ion 33, which rearranged for the most part into the altro ion 34. The equilibrium between the manno ion 33 and the altro ion 34 is approximately 1:3.     

A short path to synthesis of 4-deoxy-4-fluoroglucosaminides: methylumbelliferyl N-acetyl-4-deoxy-4-fluoro-beta-D-glucosaminide

A convenient method of synthesis of 1,6-anhydro-4-deoxy-2-O-tosyl-4-fluoro-beta-D-glucopyranose by fusion of 1,6;3,4-dianhydro-2-O-tosyl-beta-D-galactopyranose with 2,4,6-trimethylpyridinium fluoride was found. By successive action of ammonia, methyl trifluoroacetate, and acetic anhydride, the resulting compound was transformed into 1,6-anhydro-3-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-beta-D-glucopyranose, which was converted into 3,6-di-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-alpha-D-glucopyranosyl fluoride by the reaction with HF/Py. The resulting fluoride was further used as a glycosyl donor in the synthesis of methylumbelliferyl N-acetyl-4-deoxy-4-fluoro-beta-D-glucosaminide.