Topic
Pyranose
About: Pyranose is a research topic. Over the lifetime, 1619 publications have been published within this topic receiving 35348 citations. The topic is also known as: pyranoses & hexopyranose.
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24 Feb 1984TL;DR: A substantially pure pyranose-2-oxidase preparation obtained from P. obtusus, and preferably from a high-producer strain thereof, is described in this article.
Abstract: A substantially pure pyranose-2-oxidase preparation obtained from P. obtusus, and preferably from a high-producer strain thereof. The preparation is substantially free of glucosone-utilizing enzyme contaminants having measurable activity at a pH between about 4.4 and 7.0.
8 citations
TL;DR: In this article, the deamination of 2-amino-2-deoxy-D-mannose with nitrous acid gives 2-O-methyl-Dglucose in a ratio of ca. 2:1.
Abstract: The deamination of methyl 2-amino-2-deoxy-α-D-mannopyranoside with nitrous acid gives methyl 2-deoxy-α-D-erythro-hexopyranosid-3-ulose and 2-O-methyl-D-glucose in a ratio of ca. 2:1. The disputed mechanism for the deamination of 2-amino-2-deoxy-D-mannose is further discussed.
8 citations
TL;DR: In this article, photolysis of 1-glycosyl-2,3-butanodione derivatives using visible light is a mild and selective procedure for the synthesis of chiral 1-hydroxy-1-methyl-5-oxaspiro[3.5]nonan-2-one carbohydrate derivatives.
Abstract: Photolysis of 1-glycosyl-2,3-butanodione derivatives using visible light is a mild and selective procedure for the synthesis of chiral 1-hydroxy-1-methyl-5-oxaspiro[3.5]nonan-2-one carbohydrate derivatives. The results strongly suggest that stereocontrol of the cyclization is dependent on conformational and stereoelectronic factors. Further oxidative opening of the 1-hydroxy-1-methyl-2-cyclobutanone moiety affords new C-ketoside derivatives either in C- and O-glycoside series. This tandem two-step process could be considered to be a stereocontrolled 1,3-transference of an acetyl group, and it can be applied either to pyranose and furanose models.
8 citations
TL;DR: Both the ionized and the unionized structures of D-ribose preferred the pyranose conformation, which was supported by (13)C NMR experiments, and electronic redistribution via resonance and intramolecular hydrogen-bond formation were proposed to account for the stabilization of the ionization structure.
Abstract: Determination of the pKa of OH groups present in d-ribose is crucial in order to elucidate the origin and mechanism of many catalytic processes that involve the ribose unit. However, there is hardly any reports about the experimental pKa of the OH group due to the lack of an appropriate method. In this study we investigated the protonation state of OH groups in d-ribose by introducing C–D labeling and measuring the changes in the isolated C–D frequency in several isotopologues of the compound with pH. The large shift in the νC–D of d-ribose-C1-D in ionized condition compared to other deuterium-substituted d-riboses (e.g., d-ribose-C2-D, d-ribose-C3-D, etc.) confirmed that the C1–OH group preferred ionization, and the ionization pKa was 11.8. Both the ionized and the unionized structures of d-ribose preferred the pyranose conformation, which was supported by 13C NMR experiments. Electronic redistribution via resonance and intramolecular hydrogen-bond formation were proposed to account for the stabilization...
8 citations
TL;DR: The results show that carbohydrates without anchoring groups and even without hydroxyl groups can coordinate to the metal center only through very weak donors such as oxygen atoms of pyranose rings and acetoxy substituents.
8 citations