- Ultrasound accelerated synthesis of: O-alkylated hydroximides under solvent- A nd metal-free conditions
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A novel, sustainable, environmentally friendly, high substrate scope, efficient, solvent-free and metal catalyst-free method for the cross-dehydrogenative coupling (CDC) reaction between N-hydroxyphthalimide (NHPI) and benzyl/ether compounds is described. This coupling reaction proceeds through ultrasound acceleration. Compared to conventional heating conditions, the use of ultrasound techniques not only improves the reaction efficiency and enhances the reaction rate but also minimizes the side reactions.
- Jiang, Hongmei,Tang, Xiaoyue,Liu, Sihan,Wang, Lian,Shen, Haicheng,Yang, Jiankui,Wang, Huixian,Gui, Qing-Wen
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p. 10223 - 10227
(2019/12/26)
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- Cellular protection of SNAP-25 against botulinum neurotoxin/A: Inhibition of thioredoxin reductase through a suicide substrate mechanism
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Botulium neurotoxins (BoNTs) are among the most lethal toxins known to man. They are comprised of seven serotypes with BoNT/A being the most deadly; yet, there is no approved therapeutic for their intoxication or one that has even advanced to clinical trials. Botulinum neurotoxicity is ultimately governed through light chain (LC) protease SNARE protein cleavage leading to a loss of neurotransmitter release. Pharmacological attempts to ablate BoNT/A intoxication have sought to either nullify cellular toxin entry or critical biochemical junctions found within its intricate mechanism of action. In these regards, reports have surfaced of nonpeptidic small molecule inhibitors, but few have demonstrated efficacy in neutralizing cellular toxicity, a key prerequisite before rodent lethality studies can be initiated. On the basis of a lead discovered in our BoNT/A cellular assay campaign, we investigated a family of N-hydroxysuccinimide inhibitors grounded upon structure activity relationship (SAR) fundamentals. Molecules stemming from this SAR exercise were theorized to be protease inhibitors. However, this proposition was overturned on the basis of extensive kinetic analysis. Unexpectedly, inhibitor data pointed to thioredoxin reductase (TrxR), an essential component required for BoNT protease translocation. Also unforeseen was the inhibitors' mechanism of action against TrxR, which was found to be brokered through a suicide-mechanism utilizing quinone methide as the inactivating element. This new series of TrxR inhibitors provides an alternative means to negate the etiological agent responsible for BoNT intoxication, the LC protease.
- Seki, Hajime,Xue, Song,Pellett, Sabine,?ilhár, Peter,Johnson, Eric A.,Janda, Kim D.
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supporting information
p. 5568 - 5575
(2016/06/01)
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- Photoinduced electron-transfer-promoted redox fragmentation of N-alkoxyphthalimides
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A new photoinduced electron-transfer-promoted redox fragmentation of N-alkoxyphthalimides has been developed. Mechanistic experiments have established that this reaction proceeds through a unique concerted intramolecular fragmentation process. This distinctive mechanism imparts many synthetic advantages, which are highlighted in the redox fragmentation of various heterocyclic substrates.
- Zlotorzynska, Maria,Sammis, Glenn M.
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supporting information; experimental part
p. 6264 - 6267
(2012/01/15)
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- Synthesis and stereoisomerization of 2-(1-alkoxyimino-2,2,2-trifluoroethyl) -5-trimethylsilylfurans
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2-(1-Alkoxyimino-2,2,2-trifluoroethyl)-5-trimethylsilylfurans were synthesized by the condensation of 2-(trifluoroacetyl)-5-trimethylsilylfuran with alkoxyamines. According to 1H and 19F NMR spectroscopic data, the alkoxyimino group in the E-isomers descreens the H-3 and H-4 protons of the furan ring more strongly than in the Z-isomers, shifting their signals downfield. The fluorine atoms of the α-trifluoromethyl group in the Z-isomer are characterized by a downfield shift in relation to the E-isomer. 2005 Springer Science+Business Media, Inc.
- Melnik,Vorona,Veinberg,Popelis,Ignatovich,Lukevics
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p. 718 - 721
(2007/10/03)
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- Development of n new class of rate-accelerating additives for nitroxide- mediated 'living' free radical polymerization
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Acylating agents have been identified as a new class of rate accelerating additives for nitroxide-mediated 'living' free radical polymerization. It is found that addition of 1 weight percent of acetic anhydride results in a significant decrease in the reaction time, 48 to 4 hours. This decrease in reaction time leads to greater control over the polymerization process with low polydispersity materials being obtained up to 150 000 a.m.u. A possible explanation for this effect is acylation of the alkoxyamine nitrogen leading to an increase in the lability of the C-ON bond.
- Malmstroem, Eva,Miller, Robert D.,Hawker, Craig J.
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p. 15225 - 15236
(2007/10/03)
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