- Synthesis of Benzoisoselenazolones via Rh(III)-Catalyzed Direct Annulative Selenation by Using Elemental Selenium
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Isoselenazolone derivatives have attracted significant research interest because of their potent therapeutic activities and indispensable applications in organic synthesis. Efficient construction of functionalized isoselenazolone scaffolds is still challenging, and thus new synthetic approaches with improved operational simplicity have been of particular interest. In this manuscript, we introduce a rhodium-catalyzed direct selenium annulation by using stable and tractable elemental selenium. A series of benzamides as well as acrylamides were successfully coupled with selenium under mild reaction conditions, and the obtained isoselenazolones could be pivotal synthetic precursors for several organoselenium compounds. Based on the designed control experiments and X-ray absorption spectroscopy measurements, we propose an unprecedented selenation mechanism involving a highly electrophilic Se(IV) species as the reactive selenium donor. The reaction mechanism was further verified by a computational study.
- Xu-Xu, Qing-Feng,Nishii, Yuji,Uetake, Yuta,Sakurai, Hidehiro,Miura, Masahiro
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supporting information
p. 17952 - 17959
(2021/11/16)
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- Synthesis of β-acylamino furans from glucosamine
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A facile method for the synthesis of a series of novel β-acylamino furans stating from renewable monosaccharide was achieved. Glucosamine hydrochloride was selectively N-acylated with acyl chlorides in methanol/triethylamine to yield N-acyl-d-glucosamines, which were subsequently converted into β-acylamino furans through dehydration and cyclization under microwave irradiation.
- Cao, Zhi-ling,Zhu, Cong,Wu, Wen-ying,Zhu, Dan-dan,Qian, Dong,Zhu, Jian,Chang, Tian-ge,Sheng, Mei,Yang, Xiu-li,Liu, Wei-wei
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p. 472 - 484
(2021/03/17)
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- USE OF UAP INHIBITORS TO INHIBIT FLUX THROUGH THE HEXOSAMINE BIOSYNTHETIC PATHWAY
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Disclosed are UAP inhibitors to inhibit glucose flux in the hexosamine biohynthetic pathway and methods of treating a disease using the inhibitors.
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Page/Page column 62; 63
(2016/02/29)
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- A chemoenzymatic route to N-acetylglucosamine-1-phosphate analogues: Substrate specificity investigations of N-acetylhexosamine 1-kinase
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Reports an efficient chemoenzymatic production of an N-acetylhexosamine 1-phophate analogues library by N-acetylhexosamine 1-kinase (NahK) and describes the respective substrate specificity on this enzyme.
- Cai, Li,Guan, Wanyi,Kitaoka, Motomitsu,Shen, Jie,Xia, Chengfeng,Chen, Wenlan,Wang, Peng George
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supporting information; experimental part
p. 2944 - 2946
(2009/12/01)
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- β-Methyl-2-amino-2,3-didesoxyribofuranoside, a Novel Building Block for Backbone Modified Antisense Oligonucleotides
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A synthesis of the amino sugar 2-amino-2,3-didesoxyribose is described. Starting from D-glucosamine, β-methylfuranoside was obtained in eight steps in 20% yield. This carbohydrate is a novel building block for nucleosides and for backbone modified antisense oligonucleotides with 2′-5′ amide linkages.
- Winkler, Johannes,Urban, Ernst,Noe, Christian R.
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p. 109 - 116
(2007/10/03)
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- Structural modifications of antisense oligonucleotides
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Antisense oligonucleotides are efficient tools for the inhibition of gene expression in a sequence specific way. Natural oligonucleotides are decomposed rapidly in biological systems, which strongly restrict their application. In contrast, artificial oligonucleotides are designed to be more stable against degradation than the target mRNA, which results in a catalytic effect of the drug. Modification of the phosphate linkage has been the first successful strategy for antisense drug developments and Fomivirsene the first antisense drug in therapy. The launch of Fomivirsene has resulted in a revolutionary spin off to antisense research leading to a second generation of antisense oligonucleotides, which are stable against oligonucleotide cleaving enzymes. Among these, oligonucleotides bearing an alkoxy substituent in position 2′ were the most successful ones. The third generation of antisense oligonucleotides contains structure elements, which enhance the antisense action. Zwitterionic oligonucleotides show remarkable results, first, because the stability against ribozymes is largely increased, and secondly, because the electrostatic repulsion between the anionic sense and the zwitterionic antisense cords is minimized. Promising new target molecules in antisense reseach are oligonucleotide chimaeres, which enhance the antisense action (chimaeres with intercalators, chelators or polyamines) or enable an application as sequence specific detectors (chimaeres with biotin, fluorescein or radioligands).
- Urban, Ernst,Noe, Christian R.
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p. 243 - 258
(2007/10/03)
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- Biological properties of N-acyl and N-haloacetyl neuraminic acids: Processing by enzymes of sialic acid metabolism, and interaction with influenza virus
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Several unnatural N-acyl neuraminic acids (N-propionyl, N-hexanoyl, N-benzoyl, N-trifluoroacetyl, N-chloroacetyl, N-difluoroacetyl) were prepared enzymatically using immobilised sialic acid aldolase. N-Trifluoroacetyl-, N-chloroacetyl- and N-difluoroacetyl neuraminic acids were shown to enhance up to 10-fold the rate of association of influenza virus A to a sialoglycolipid neomembrane by surface plasmon resonance, and were found to act as weak inhibitors (Kiapp 0.45-2.0 mM) of influenza virus neuraminidase. The N-propionyl, N-chloroacetyl- and N-difluoroacetyl neuraminic acids were found to be substrates for recombinant Escherichia coli CMP sialate synthase, to give the corresponding CMP-N-acyl-neuraminic acids. CMP-N-propionyl neuraminic acid was found not to be a substrate for CMP-N-acetyl neuraminic acid hydroxylase from pig submandibular gland. Copyright
- Humphrey, Andrew J,Fremann, Claire,Critchley, Peter,Malykh, Yanina,Schauer, Roland,Bugg, Timothy D.H
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p. 3175 - 3185
(2007/10/03)
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- Palladium-catalyzed asymmetric allylic substitution reactions using new chiral phosphinite-oxazoline ligands derived from D-glucosamine
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Novel 2-alkyl- or 2-aryl-4,5-(4,6-O-benzylidene-3-O-(diphenylphosphino)- 1,2-dideoxy-α-D-glucopyrano)-[2,1-d]-2-oxazolines (5a-f) have been prepared from D-glucosamine hydrochloride. They work effectively as chiral ligands and provide a high level of enantiomeric excess in palladium-catalyzed allylic alkylation and amination reactions. The allylic alkylation of 1,3-diphenyl-3- acetoxyprop-1-ene with dimethyl malonate proceeds smoothly in the presence of 0.25 mol % [Pd(η3C3H5)Cl]2 and the chiral ligand 5a having the smallest substituent on oxazoline at 0 °C within 6 h to furnish the highest enantiomeric excess (96% ee). The ligand 5a is also effective for the Pd- catalyzed amination of ethyl 1,3-diphenylprop-2-enyl carbonate, leading to the corresponding allylic amine in 94% ee. The full scope and limitations using ligands 5a-f in the allylic substitution reactions are described.
- Yonehara, Koji,Hashizume, Tomohiro,Mori, Kenji,Ohe, Kouichi,Uemura, Sakae
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p. 9374 - 9380
(2007/10/03)
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- Palladium-catalysed asymmetric allylic alkylation using new chiral phosphinite-nitrogen ligands derived from D-glucosamine
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Novel phosphinite-nitrogen chiral ligands synthesized from D-glucosamine furnish a high level of enantiomeric excess (up to 96% ee] in palladium-catalysed allylic alkylation.
- Yonehara, Koji,Hashizume, Tomohiro,Mori, Kenji,Obe, Kouichi,Uemura, Sakae
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p. 415 - 416
(2007/10/03)
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- New Synthetic Methods and Reagents for Complex Carbohydrates. II. Synthesis of 2-Acylamino-2-deoxy-D-glucopyranose Derivatives by Dimethylphosphinothioic Anhydride Method
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Dimethylphosphinothioic (Mpt) mixed anhydrides of carboxylic acids were found to be useful for N-acylation of 2-amino-2-deoxy-D-glucopyranose derivatives without protecting the hydroxyl functions.By this method, N-acylation of 2-amino-2-deoxy-D-glucopyran
- Inazu, Toshiyuki,Hosokawa, Hideaki,Anemiya, Masahide
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p. 4467 - 4469
(2007/10/02)
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- 3,3'-(Phenylphosphinylidene)bis and 3,3'-(Phenylphosphinylidene)bis. New Activating Agents
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New activating agents, 3,3'-(phenylphophinylidene)bis (4) and 3,3'-(phenylphosphinylidene)bis (5), were readily prepared by the reaction of phenylphosphonic dichloride (3) with 2(3H)-benzoxazolone (1) and 2(3H)-benzothiazolone (2) respectively in the presence of triethylamine at room temperature.The new activating agents 4 and 5 were found to be useful for the preparation of amides, esters, and dipeptides under mild conditions.Furthemore, the direct polycondensation of isophthalic acid with aromatic diamines using the activating agent 4 in the presence of pyridine proceeded fast at room temperature to produce polyamides with inherent viscosities up to 0.80 dL/g.
- Ueda, Mitsuru,Mochizuki, Amane,Hiratsuka, Ichiro,Oikawa, Hideaki
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p. 3291 - 3297
(2007/10/02)
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