- On the hydrogenation of glycosyl oxazolines
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An investigation is undertaken into the propensity of glycosyl oxazolines to undergo reductive cleavage by catalytic hydrogenation. Results indicate that the protecting groups on carbohydrate hydroxyl groups modulate the rate of glycosyl oxazoline reducti
- Cox, Daniel J.,Parsons, Thomas B.,Fairbanks, Antony J.
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- Effect of Lewis acid on catalytic dehydration of a chitin-derived sugar alcohol
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Chitin is an abundant marine biomass consisting of N-acetylglucosamine (NAG) units. NAG is a source for 2-acetamide-2-deoxyisosorbide (ADI), a condensed five-membered ring compound potentially useful for producing nitrogen-containing polymers. The synthetic route of ADI from NAG consists of hydrogenation of NAG to 2-acetamide-2-deoxysorbitol (ADS) by a supported metal catalyst and subsequent dehydration reaction by a Br?nsted acid catalyst. However, the dehydration step has remained a challenge due to low reactivity of the substrate and low selectivity. Here, we report a combination of Br?nsted acid and Lewis acid catalysts for accelerating the ADS dehydration. The additional use of a catalytic amount of ytterbium triflate in the ADS dehydration by trifluoromethanesulfonic acid catalyst shortens the reaction time by one third and moreover increases the yield of ADI by changing regio-selectivity of the reaction. Mechanistic roles of the ytterbium complex are discussed based on the experimental evidences and density functional theory calculations.
- Sagawa, Takuya,Kobayashi, Hirokazu,Fukuoka, Atsushi
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- Identification, characteristics and mechanism of 1-deoxy-N-acetylglucosamine from deep-sea Virgibacillus dokdonensis MCCC 1A00493
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Xanthomonas oryzae pv. Oryzae, which causes rice bacterial blight, is one of the most destructive pathogenic bacteria. Biological control against plant pathogens has recently received increasing interest. 1-Deoxy-N-acetylglucosamine (1-DGlcNAc) was extracted from the supernatant of Virgibacillus dokdonensis MCCC 1A00493 fermentation through antibacterial bioassay-guided isolation. Its structure was elucidated by LC/MS, NMR, chemical synthesis and time-dependent density functional theory (TD-DFT) calculations. 1-DGlcNAc specifically suppressed X. oryzae pv. Oryzae PXO99A (MIC was 23.90 μg/mL), but not other common pathogens including Xanthomonas campestris pv. campestris str.8004 and Xanthomonas oryzae pv. Oryzicola RS105. However, its diastereomer (2-acetamido-1,5-anhydro-2-deoxy-D-mannitol) also has no activity to X. oryzae pv. Oryzae. This result suggested that activity of 1-DGlcNAc was related to the difference in the spatial conformation of the 2-acetamido moiety, which might be attributed to their different interactions with a receptor. Eighty-four unique proteins were found in X. oryzae pv. Oryzae PXO99A compared with the genome of strains8004 and RS105 by blastp. There may be unique interactions between 1-DGlcNAc and one or more of these unique proteins in X. oryzae pv. Oryzae. Quantitative real-time PCR and the pharmMapper server indicated that proteins involved in cell division could be the targets in PXO99A. This research suggested that specificity of active substance was based on the active group and spatial conformation selection, and these unique proteins could help to reveal the specific mechanism of action of 1-DGlcNAc against PXO99A.
- Huang, Dian,Shao, Zong-Ze,Yu, Yi,Cai, Min-Min,Zheng, Long-Yu,Li, Guang-Yu,Yu, Zi-Niu,Yi, Xian-Feng,Zhang, Ji-Bin,Hao, Fu-Hua
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- COMPOUNDS AND METHODS FOR TREATING VIRAL INFECTION
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The present disclosure relates to compounds and methods for treating symptoms or sequelae resulting from viral infection, including influenza, rhinovirus, or betacoronavirus infection, such as human coronaviruses such as SARS coronaviruses, MERS coronaviruses, and COVID-19, including Acute Respiratory Distress Syndrome (ARDS) associated with the viral infection.
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Paragraph 088-089; 095-096
(2022/03/22)
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- Characteristic activity of phosphorous acid in the dehydration condensation of a chitin-derived nitrogen-containing sugar alcohol
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Chitin is a potential resource for the production of renewable organonitrogen compounds, as it contains biologically fixed nitrogen. Hydrolysis of chitin followed by hydrogenation gives the sugar alcohol named 2-acetamido-2-deoxysorbitol (ADS). The dehydration condensation of ADS produces 2-acetamido-2-deoxyisosorbide (ADI), which is a prospective precursor of nitrogen-containing polymers. However, the conversion of ADS to ADI in previous works needed a large amount of CF3SO3H as a superstrong acid catalyst, which is high cost and requires special corrosion-resistant equipment. In this work, we have found that H3PO3, a weak acid, can convert ADS to ADI. Possibly, H3PO3alters the reaction mechanism from a simple acid-catalysed dehydration cyclisation to a cyclisationviaphosphite esters. Density functional theory calculations suggest that the modified pathwayviathe phosphite esters significantly reduces the activation energy. In addition, the reducing ability of the acid likely decreases the formation of condensation by-products.
- Yang, Cheng,Sagawa, Takuya,Fukuoka, Atsushi,Kobayashi, Hirokazu
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p. 7228 - 7234
(2021/09/28)
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- Design, Synthesis, and Preliminary Biological Evaluation of GlcNAc-6P Analogues for the Modulation of Phosphoacetylglucosamine Mutase 1 (AGM1/PGM3)
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A library of GlcNAc 6- or 1-phosphate analogues was designed, and each compound was evaluated computationally through docking studies for its binding affinity to AGM1/PGM3. The compounds with the highest binding affinity, as ranked through a docking score, were synthesised and screened for their ability to inhibit the production of UDP-GlcNAc. A glycofused oxazoline analogue showed good inhibition, and gave significant results in vitro.
- Paiotta, Alice,D'Orazio, Giuseppe,Palorini, Roberta,Ricciardiello, Francesca,Zoia, Luca,Votta, Giuseppina,De Gioia, Luca,Chiaradonna, Ferdinando,La Ferla, Barbara
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p. 1946 - 1952
(2018/05/15)
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- Synthesis of 6-, 7- and 8-carbon sugar analogues of potent anti-influenza 2,3-didehydro-2,3-dideoxy-N-acetylneuraminic acid derivatives
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Analogues of the potent anti-influenza A and B compound, 4-guanidino-Neu5Ac2en, are described in which the stereochemically demanding C-6-glycerol side-chain is truncated.Syntheses of the one- and two-carbon side-chain analogues, of both 4-guanidino- and 4-amino-Neu5Ac2en, are presented, as well as the syntheses of analogues lacking any side-chain.Whilst complete removal of the C-6 side-chain abolishes activity, a stepwise increase in inhibition of influenza neuraminidase and influenza A and B in cell culture with increasing C-6 chain length is observed.The one-carbon, hydroxymethyl derivative retains significant activity to represent a suitable lead in the search for neuraminidase inhibitors of reduced stereochemical demand and synthetic complexity.
- Bamford, Mark J.,Pichel, Julia Castro,Husman, Wahid,Patel, Bina,Storer, Richard,Weir, Niall G.
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p. 1181 - 1188
(2007/10/02)
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- Synthesis and biological activity of some 1-N-substituted 2-acetamido-2-deoxy-beta-D-glycopyranosylamine derivatives and related analogs.
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Several 1-N-substituted derivative [haloacetyl-, glycyl-, (dimethyl)amino-acetyl-, azidoacetyl-, trifluoroacetyl-, and trifluoromethylsulfonyl-] of 2-acetamido-2-deoxy-3,4,6-tri-O-acetyl-beta-D-glucopyranosylamine (1) were synthesized as potential metabolic inhibitors of cellular-membrane glycoconjugates. Several fully acetylated derivatives were found to inhibit growth of mouse mammary adenocarcinoma TA3, leukemia L1210, or leukemia P-288 cells at 1-0.01 mM concentration in vitro. Some of these derivatives were less active after O-deacetylation. Analogs of 1 in which NH2-1 was replaced by OH- or OAc-1 were also active on the same cell systems. The growth-inhibitory activity was correlated with inhibition of the incorporation of 2-amino-deoxy-D-glucose and L-leucine into a macromolecular fraction.
- Paul,Bernacki,Korytnyk
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