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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TL;DR: An allylic methoxy substituent at C-3 in C-2 vinyl glycals (1b,c) induces complete antiπ-facial selectivity in the thermal Diels-Alder reaction with malefic anhydride; in contrast, products resulting from anti and syn approaches are observed when linear acetylenic compounds are employed as dienophiles.
Abstract: An allylic methoxy substituent at C-3 in C-2 vinyl glycals (1b,c) induces complete antiπ-facial selectivity in the thermal Diels–Alder reaction with malefic anhydride; in contrast, products resulting from anti and syn approaches are observed when linear acetylenic compounds are employed as dienophiles; the latter adducts readily aromatize to afford a mixture of products with the pyranose ring unchanged (8) and opened (9).
12 citations
TL;DR: Pyranose oxidase purified from mycelia of the basidiomycete fungi Trametes versicolor and Oudemansiella mucida catalyzed oxidation of d‐galactose successively at C‐2 and C‐3 to d‐threo‐hexos‐2,3‐diulose in the yields up to 80%.
12 citations
TL;DR: The pyranose members of the pyrrolomorpholine spiroketal family have been synthesized by stereoselective spirocyclizations of a common glycal precursor, leading to the identification of novel 2-hydroxy analogues with more potent antioxidant activities than the natural products.
Abstract: The pyranose spiroketal natural products pollenopyrroside A and shensongine A (also known as xylapyrroside A, ent-capparisine B) have been synthesized by stereoselective spirocyclizations of a common C1-functionalized glycal precursor. In conjunction with our previously reported syntheses of the corresponding furanose isomers, this provides a versatile family-level synthesis of the pyrrolomorpholine spiroketal natural products and analogues. In rat mesangial cells, hyperglycemia-induced production of reactive oxygen species, which is implicated in diabetic nephropathy, was inhibited by pollenopyrroside A and shensongine A with mid-μM IC50 values, while unnatural C2-hydroxy analogues exhibited more potent, sub-μM activity.
12 citations
TL;DR: In this paper, a combination of NMR measurements and statistical mechanics modelling was employed to predict a population inversion between furanose and pyranose at equilibrium at high temperatures.
Abstract: The exclusive presence of β-D-ribofuranose in nucleic acids is still a conundrum in prebiotic chemistry, given that pyranose species are substantially more stable at equilibrium. However, a precise characterisation of the relative furanose/pyranose fraction at temperatures higher than about 50 °C is still lacking. Here, we employ a combination of NMR measurements and statistical mechanics modelling to predict a population inversion between furanose and pyranose at equilibrium at high temperatures. More importantly, we show that a steady temperature gradient may steer an open isomerisation network into a non-equilibrium steady state where furanose is boosted beyond the limits set by equilibrium thermodynamics. Moreover, we demonstrate that nonequilibrium selection of furanose is maximum at optimal dissipation, as gauged by the temperature gradient and energy barriers for isomerisation. The predicted optimum is compatible with temperature drops found in hydrothermal vents associated with extremely fresh lava flows on the seafloor.
12 citations
TL;DR: In this article, the peracetate of plaxyloside, a glycolipid composed of a C35 linear polyisoprenoid alcohol aglycone and a linear carbohydrate chain made up of six β-xylopyranose units, has been determined on the basis of spectral and chemical data.
12 citations