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: The RNA aptamer complexes with tobramycin and neomycin B utilize common architectural principles to generate RNA-binding pockets for the bound aminoglycoside antibiotics.
116 citations
TL;DR: In this paper, the α- and β-anomers of the pent-4-enyl D-glucopyranoside (10) with N-bromosuccinimide in dry acetonitrile generated stereospecifically α-D-glocopyranoylacetonitrilium ion (5α), which reacts in situ with 2-chlorobenzoic acid to afford the αimide (8α), in contrast to that predicted by the reverse anomeric effect and previous work on trapping carbohydrate aceton
Abstract: Reaction of the α- and β-anomers of the pent-4-enyl D-glucopyranoside (10) with N-bromosuccinimide in dry acetonitrile generated stereospecifically the α-D-glucopyranosylacetonitrilium ion (5α), which reacts in situ with 2-chlorobenzoic acid to afford the α-imide (8α). The result is in contrast to that predicted by the reverse anomeric effect and previous work on trapping carbohydrate acetonitrilium ions with 2-chlorobenzoic acid. The unusually large J12 7.3 Hz for 1-H of (8α) is rationalised by a substantial flattening of the pyranose ring at C-1 and C-2. Molecular dynamic studies on the model α-imide (12) support a flattened 4C1, conformation. Treatment of imide (8α) with sodium methoxide leads to the α-2-chlorobenzamide (9α), which was substantiated by independent synthesis of the β-2-chlorobenzamide (9β).
115 citations
TL;DR: In this article, per-O-acetylation of sugars with stoichiometric acetic anhydride and catalytic iodine proceeds in high yield (90-99%) to give exclusively pyranose products as anomeric mixtures.
Abstract: Solvent-free per-O-acetylation of sugars with stoichiometric acetic anhydride and catalytic iodine proceeds in high yield (90-99%) to give exclusively pyranose products as anomeric mixtures. Without workup, subsequent anomeric substitution employing iodine in the presence of hexamethyldisilane (i.e., TMS-I generated in situ) gives the corresponding glycosyl iodides in 75-95% isolated yield. Alternatively, and without workup, further treatment with dimethyl disulfide or thiol (ethanethiol or thiocresol) gives anomerically pure thioglycosides in more than 75% overall yield.
112 citations
TL;DR: The total synthesis of the title compound (1), starting with (R)-(−)-α-phellandrene (6), has been accomplished as discussed by the authors, which rigorously proves the relative stereochemical relationship of the diterpenoid and carbohydrate domains of eleutherobin.
Abstract: The total synthesis of the title compound (1), starting with (R)-(−)-α-phellandrene (6), has been accomplished. The synthesis rigorously proves the relative stereochemical relationship of the diterpenoid and carbohydrate domains of eleutherobin. Key reactions included a Nozaki−Kishi ring closure to produce a furanophane (see 37 → 38), a pyranose to furanose transposition (see 50 → 47), and a novel oxycarbaglycosidation (cf. 58 → 87) for joining the two domains.
112 citations
TL;DR: The ‘carrier’ system in the surface of the human erythrocyte, facilitating passage of monosaccharides through the cell membrane, reacts preferentially with those sugars in which the pyranose ring tends to assume the particular ‘chair’ shape designated by Reeves as the ‘C1’ conformation.
Abstract: The ‘carrier’ system in the surface of the human erythrocyte, facilitating passage of monosaccharides through the cell membrane, reacts preferentially with those sugars in which the pyranose ring tends to assume the particular ‘chair’ shape designated by Reeves as the ‘C1’ conformation. This novel type of steric specificity was revealed in a comparative study of fourteen aldoses (6 pentoses, 5 hexoses, and 3 deoxyhexoses), in which the dissociation constants of the carrier-sugar complexes were derived from the kinetics of the transfer process and of the competitive inhibition by phloretin. The sequence of increasing affinities thus determined paralleled the sequence of increasing relative stability in the C1 conformation as dictated by the distribution of substituent groups between axial and equatorial positions on the ring. Sugars predominantly stable in the other chair conformation (1C) showed extremely low affinity. Since no instance of biological utilization of the latter sugars has apparently yet bee...
112 citations