On Walden-Inversion

Levene, P. A.; Mikeska, L. A.

doi:10.1126/science.59.1520.168

Cited by 18 publications

(20 citation statements)

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“…We isolated mixtures of the 3-keto derivative 27 with the lactones 53 and 54 [50] or the acid 29, [50,51] and even the pentulose 28 [48] in differing ratios (Scheme 7). 1-Deoxy-d-ribulose 28 was characterised by NMR spectroscopy, and the C-1 oxidation products were identified by acetylation to the derivatives 55, [52] 56 [53] and 57.…”

Section: Substratementioning

confidence: 99%

Rare Keto-Aldoses from Enzymatic Oxidation: Substrates and Oxidation Products of Pyranose 2-Oxidase

Freimund¹,

et al. 1998

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Pyranose oxidases are known to oxidise d-glucose, d-xylose and lsorbose to keto-aldoses, biochemically interesting compounds that may also be used for synthetic purposes in a variety of reactions. In this study pyranose oxidase from the basidiomycete Peniophora gigantea was investigated, and it was found that this enzyme is able to oxidise a broad variety of substrates very effectively. In analogy to its natural mode of action, most substrates are oxidised regioselectively in position 2. Certain compounds, however, are converted into 3-keto derivatives, and the enzyme even exhibits transfer potential, that is, disaccharides are formed from bglycosides of higher alcohols. Substrates that may be oxidised at C-2 in yields between 40 ± 98 % are d-allose, d-galactose, 6-deoxy-d-glucose, d-gentiobiose, a-d-glucopyranosyl fluoride and the very interesting 3-deoxy-d-glucose. 1,5-Anhydro-d-glucitol (1-deoxy-d-glucose) is very effectively oxidised in position 2 in 98 % yield and additionally gives a product of dioxidation at C-2 and C-3 upon prolonged reaction time. Selective oxidation at C-3 was found for 2-deoxyd-glucose in very good yields and for methyl b-d-gluco-and methyl b-galactopyranoside in lower yields. All oxidation products were unequivocally characterised by NMR spectroscopy and/or chemical derivatisation. In addition, the kinetic data of the enzymatic reactions were determined for all substrates. On the basis of these data and the structural characteristics of the substrates, a model for the minimal structural requirements of the enzyme ± substrate interaction is suggested. The enzyme presumably uses two different binding modes for the regioselective C-2 and the C-3 oxidations, which are described.

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Section: Substratementioning

confidence: 99%

Rare Keto-Aldoses from Enzymatic Oxidation: Substrates and Oxidation Products of Pyranose 2-Oxidase

Freimund¹,

et al. 1998

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“…Nevertheless, it seems highly probable that the levorotatory 2-hydroxypentadecanoic acid prepared from ustilic acid B and the levorotatory 2-hydroxyhexadecanoic acid, rotations measured in ethanol, isolated from the wool wax of Merino sheep by ICuwata (13), posskssed configurations opposite to the homologous dextrorotatory 2~-hydroxyacids, rotations measured in water. Levene (19) has pointed out that the sodium salts of aldonic acids are more dextrorotatory than the free acids when the 2-carbon atom has the D-configuration and this relationship is well established for thesimple 2-hydroxyacids (20,24). As shown in Table I , the molar rotations measured in water of the sodium salts of normal 2-hydroxyacids increase with increasing molecular weight.…”

Section: Introductionmentioning

confidence: 77%

Biochemistry of the Ustilaginales: Viii. The Structures and Configurations of the Ustilic Acids

Lemieux¹

1953

Can. J. Chem.

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Methanolysis of ustilagic acid a r~d hydrolysis of the methyl esters for~lled yielded a crystalline acidic fraction which was essentially a mixture of two substances termed the ustilic acids A and B. The acids were separated as their isopropylidene derivatives. The ustilic acids cocrystallize to mixtures with melting points intermediate between those of the pure compounds. Conversion of ustilic acid A, 1n.p. 112-113" C., [O]D -8" in methanol, which made up about 70% of the mixture, by hydrogenolysis to palmitic acid, by oxidation with chromic oxide to pentadecanedioic acid, and by lead tetraacetate oxidation followed by hydrogenation to 15-hydroxypentadecanoic acid showed the substance to be a n optically active form of 15,16-dihyd

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“…'The utility of the diastereomeric C~'M(NO)(~~-CH,P~)(~~-~~CR) complexes for this purpose is the subject of ongoing research, the initial results of which indicate that resolution of the CD* complexes may be more easily achieved than that of the bp complexes. Silver carboxylates are the reagents of choice since optically active carboxylic acids can be readily obtained, either commercially or by established resolution procedures (19), and silver carboxylates are easily prepared from these acids (20).…”

Section: Mecn -Agcimentioning

confidence: 99%

Synthesis, characterization, and properties of [Cp*M(NO)(η²-CH₂Ph)-(NCMe)]BF₄salts (M = Mo, W) and related complexes: the stabilizing influence of benzyl ligands

Dryden¹,

Legzdins²,

Sayers³

et al. 1995

Can. J. Chem.

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On Walden-Inversion

Cited by 18 publications

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Rare Keto-Aldoses from Enzymatic Oxidation: Substrates and Oxidation Products of Pyranose 2-Oxidase

Rare Keto-Aldoses from Enzymatic Oxidation: Substrates and Oxidation Products of Pyranose 2-Oxidase

Biochemistry of the Ustilaginales: Viii. The Structures and Configurations of the Ustilic Acids

Synthesis, characterization, and properties of [Cp*M(NO)(η²-CH₂Ph)-(NCMe)]BF₄salts (M = Mo, W) and related complexes: the stabilizing influence of benzyl ligands

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On Walden-Inversion

Cited by 18 publications

References 0 publications

Rare Keto-Aldoses from Enzymatic Oxidation: Substrates and Oxidation Products of Pyranose 2-Oxidase

Rare Keto-Aldoses from Enzymatic Oxidation: Substrates and Oxidation Products of Pyranose 2-Oxidase

Biochemistry of the Ustilaginales: Viii. The Structures and Configurations of the Ustilic Acids

Synthesis, characterization, and properties of [Cp*M(NO)(η2-CH2Ph)-(NCMe)]BF4salts (M = Mo, W) and related complexes: the stabilizing influence of benzyl ligands

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Synthesis, characterization, and properties of [Cp*M(NO)(η²-CH₂Ph)-(NCMe)]BF₄salts (M = Mo, W) and related complexes: the stabilizing influence of benzyl ligands