Halogen and nucleoside derivatives of acyclic 2-amino-2-deoxy-D-glucose. III

Wolfrom, M. L.; Conigliaro, P.J.

doi:10.1016/s0008-6215(00)81391-9

Cited by 12 publications

(3 citation statements)

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“…An alternative to the approach described in the literature (29) was chosen to prepare large quantities of this compound. Under an atmosphere of nitrogen, to a solution of 2-deoxy-3,4,6-tri-O-acetyl-2-trifluoroacetamido--D-glucopyranosyl bromide (3.48 g, 7.5 mmol) (46) in anhydrous acetonitrile (30 mL) was added CaSO 4 (2 g). To a different solution, also under an atmosphere of nitrogen, containing 2,6-lutidine (1.86 mL, 18.8 mmol, 2.5 equiv) and p-nitrophenol (dried in vacuo overnight, 2.1 g, 15.1 mmol, 2 equiv) in anhydrous acetonitrile (30 mL) was added CaSO 4 (2 g).…”

Section: Methodsmentioning

confidence: 99%

“…Synthesis. The syntheses of pNPGlcNAcF 2 (3) (29) and 2-deoxy-3,4,6-tri-O-acetyl-2-trifluoroacetamido-β-D-glucopyranosyl bromide (46) were performed as previously described.…”

Section: Methodsmentioning

confidence: 99%

“…An alternative to the approach described in the literature (29) was chosen to prepare large quantities of this compound. Under an atmosphere of nitrogen, to a solution of 2-deoxy-3,4,6-tri-O-acetyl-2trifluoroacetamido-β-D-glucopyranosyl bromide (3.48 g, 7.5 mmol) (46) ). These two separate slurries were then stirred at room temperature for 30 min, after which time the mixture containing the phenol was cannulated into the flask containing the glycosyl bromide.…”

Section: Methodsmentioning

confidence: 99%

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Detailed Comparative Analysis of the Catalytic Mechanisms of β-N-Acetylglucosaminidases from Families 3 and 20 of Glycoside Hydrolases

2005

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Beta-N-acetylglucosaminidases are commonly occurring enzymes involved in the degradation of polysaccharides and glycoconjugates containing N-acetylglucosamine residues. Such enzymes have been classified into glycoside hydrolase families 3 and 20 and are believed to follow distinct chemical mechanisms. Family 3 enzymes are thought to follow a standard retaining mechanism involving a covalent glycosyl enzyme intermediate while family 20 enzymes carry out a substrate-assisted mechanism involving the transient formation of an enzyme-sequestered oxazoline or oxazolinium ion intermediate. Detailed mechanistic analysis of representatives of these two families provides support for these mechanisms as well as detailed insights into transition state structure. Alpha-secondary deuterium kinetic isotope effects of kH/kD = 1.07 and 1.10 for Streptomyces plicatus beta-hexosaminidase (SpHex) and Vibrio furnisii beta-N-acetylglucosaminidase (ExoII) respectively indicate transition states with oxocarbenium ion character in each case. Brønsted plots for hydrolysis of a series of aryl hexosaminides are quite different in the two cases. For SpHex a large degree of proton donation is suggested by the relatively low value of beta(lg) (-0.29) on kcat/Km, compared with a beta(lg) of -0.79 for ExoII. Most significantly the Taft plots derived from kinetic parameters for a series of p-nitrophenyl N-acyl glucosaminides bearing differing levels of fluorine substitution in the N-acyl group are completely different. A very strong dependence (slope = -1.29) is seen for SpHex, indicating direct nucleophilic participation by the acetamide, while essentially no dependence (0.07) is seen for ExoII, suggesting that the acetamide plays purely a binding role. Taken together these data provide unprecedented insight into enzymatic glycosyl transfer mechanisms wherein the structures of both the nucleophile and the leaving group are systematically varied.

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Section: Methodsmentioning

confidence: 99%

“…Synthesis. The syntheses of pNPGlcNAcF 2 (3) (29) and 2-deoxy-3,4,6-tri-O-acetyl-2-trifluoroacetamido-β-D-glucopyranosyl bromide (46) were performed as previously described.…”

Section: Methodsmentioning

confidence: 99%

“…An alternative to the approach described in the literature (29) was chosen to prepare large quantities of this compound. Under an atmosphere of nitrogen, to a solution of 2-deoxy-3,4,6-tri-O-acetyl-2trifluoroacetamido-β-D-glucopyranosyl bromide (3.48 g, 7.5 mmol) (46) ). These two separate slurries were then stirred at room temperature for 30 min, after which time the mixture containing the phenol was cannulated into the flask containing the glycosyl bromide.…”

Section: Methodsmentioning

confidence: 99%

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