- Control of RNA with quinone methide reversible acylating reagents
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Caging RNA by polyacylation (cloaking) has been developed recently as a simple and rapid method to control the function of RNAs. Previous approaches for chemical reversal of acylation (uncloaking) made use of azide reduction followed by amine cyclization, requiring ~2-4 h for the completion of cyclization. In new studies aimed at improving reversal rates and yields, we have designed novel acylating reagents that utilize quinone methide (QM) elimination for reversal. The QM de-acylation reactions were tested with two bioorthogonally cleavable motifs, azide and vinyl ether, and their acylation and reversal efficiencies were assessed with NMR and mass spectrometry on model small-molecule substrates as well as on RNAs. Successful reversal both with phosphines and strained alkenes was documented. Among the compounds tested, the azido-QM compoundA-3displayed excellent de-acylation efficiency, witht1/2for de-acylation of less than an hour using a phosphine trigger. To test its function in RNA caging,A-3was successfully applied to control EGFP mRNA translationin vitroand in HeLa cells. We expect that this molecular caging strategy can serve as a valuable tool for biological investigation and control of RNAs bothin vitroand in cells.
- Jash, Biswarup,Jun, Yong Woong,Kool, Eric T.,Park, Hyun Shin,Xiao, Lu
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supporting information
p. 8367 - 8376
(2021/10/12)
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- Oxidation of terminal diols using an oxoammonium salt: A systematic study
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A systematic study of the oxidation of a range of terminal diols is reported, employing the oxoammonium salt 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (4-NHAc-TEMPO+ BF4-) as the oxidant. For substrates bearing a hydrocarbon chain of seven carbon atoms or more, the sole product is the dialdehyde. A series of post-oxidation reactions have been performed showing that the product mixture resulting from the oxidation step can be taken on directly to a subsequent transformation. For diols containing four to six carbon atoms, the lactone product is the major product upon oxidation. In the case of 1,2-ethanediol and 1,3-propanediol, when using a 1 : 0.5 stoichiometric ratio of substrate to oxidant, the corresponding monoaldehyde is formed which reacts rapidly with further diol to yield the acetal product. This is of particular synthetic value given both the difficulty of their preparation using other approaches and also their potential application in further reaction chemistry.
- Miller, Shelli A.,Bobbitt, James M.,Leadbeater, Nicholas E.
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supporting information
p. 2817 - 2822
(2017/04/04)
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- PROCESS FOR THE MANUFACTURE OF FLUOROSURFACTANTS
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This invention pertains to a novel process for the manufacture of a perfluorooxycarboxylate of formula (I): RfO-CF2CF2-O-CF2-COOXa (I) wherein Rf is a perfluoro(oxy)alkyl group, and Xa is H, a monovalent metal or an ammonium group of formula NRN4, with RN, equal or different at each occurrence, being H or a C1-6 hydrocarbon group, said process comprising: (A) reacting a perfluorovinylether of formula Rf-O-CF=CF2 with an ethylene glycol derivative selected among ethylene glycol (HO-CH2CH2-OH), glycolic acid (HO-CH2-COOH), glycolaldheyde (HO-CH2-CHO) and protected derivatives thereof, so as to yield the corresponding addition product of formula Rf-O-CFH-CF2-O-CH2-E, with Rf having the same meaning as above detailed, and E being selected among -CH2OH, -COOH and -CHO; (B) optionally protecting functional group E with suitable chemistry; (C) fluorinating said (protected) addition product to yield the corresponding perfluorinated addition product; (D) optionally deprotecting said perfluorinated addition product to yield corresponding acyl fluoride of formula Rf-O-CF2-CF2-O-CF2-C(O)F; (E) hydrolyzing and, optionally, neutralizing, said acyl fluoride for yielding the perfluorooxycarboxylate of formula (I).
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Page/Page column 12
(2010/04/03)
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- Benzimidazole compound
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An object of the present invention is to provide a novel chemical compound useful as a therapeutic or prophylactic agent for acid-related diseases, having an excellent inhibitory effect against gastric acid secretion, an excellent effect of maintaining the inhibitory effect against gastric acid secretion, thereby maintaining intragastric pH high for a long time, and having more safety and appropriate physicochemical stability. Provided is a compound represented by where R1 and R3 may be the same or different and each represent a hydrogen atom or a C1-C6 alkyl group; R2 represents (5,5-dimethyl-1,3-dioxan-2-yl)methoxy group, 5,7-dioxaspiro[2.5]oct-6-ylmethoxy group, 1,5,9-trioxaspiro[5.5]undec-3-ylmethoxy group, or (2,2-dimethyl-1,3-dioxan-5-yl)methoxy group; R4, R5, R6 and R7 represent a hydrogen atom, halogen atom, C1-C6 alkyl group, C1-C6 haloalkyl group, C1-C6 alkoxy group or C1-C6 haloalkoxy group; and W1 represents a single bond, methylene or ethylene group, a salt thereof or a solvate of these.
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Page/Page column 82
(2008/06/13)
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- Liquid-phase Oxidation of 1,2-Ethane Diol
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The oxidation rate and the kind of oxidation products in the reaction of 1,2-ethane diol (1) with molecular oxygen in liquid phase at 150 deg C were investigated. 1 has a very low oxidation rate.Cu-, Zn-, Fe-, Co- and Al-acetylacetonates as catalysts increase the reaction rate.The main-products of the investigated reaction are the 1,3-dioxolan (2), the 2-methyl-1,3-dioxolan (3) and the 2-methylol-1,3-dioxolan (4).The formation of formic and acetic acids and of the 1,3-dioxolanes is proved by GC, DC and HPLC.
- Schnurpfeil, D.,Maurer, G.
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p. 307 - 310
(2007/10/02)
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- Aminopolycarboxylic acids and derivatives thereof
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There are provided chelating agents particularly useful for the preparations of diagnostic and therapeutic agents for magnetic resonance imaging, scintigraphy, ultrasound imaging, radiotherapy and heavy metal detoxification, said agents being compounds of formula X--CHR1 --NZ--(CHR1)n --A--(CHR1)m --NZ--CHR1 --X wherein (each of the groups Z is a group --CHR1 X or the groups Z together are a group --(CHR1)q --A'--(CHR1)r --, where A' is an oxygen or sulphur atom or a group --N--Y; A is a group --N--Y or A--(CHR1)m -- represents a carbon-nitrogen bond or, when the groups Z together are a group --(CHR1)q --A'--(CHR1)r --, A may also represent an oxygen or sulphur atom; each Y, which may be the same or different, is a group --(CHR1)p --N(CHR1 X)2 or a group --CHR1 X; each X, which may be the same or different, is a carboxyl group or a derivative thereof or a group R1 ; each R1, which may be the same or different, is a hydrogen atom, a hydroxyalkyl group or an optionally hydroxylated alkoxy or alkoxyalkyl group; n, m, p, q and r are each 2, 3 or 4; with the provisos that at least two nitrogens carry a --CHR1 X moiety wherein X is a carboxyl group or a derivative thereof, that each --CHR1 X moiety is other than a methyl group, and that unless A' is oxygen or sulphur or A is N--(CHR1)p --N(CHR1 X)2 at least one R1 is other than hydrogen) and salts thereof.
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- A kinetic study of the alkaline hydrolysis of four-coordinated phosphorus (PIV) compounds. Impact of conformational transmission in the transiently formed five-coordinated (PV-TBP) intermediates on reaction rate and product distribution
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It can be shown that alkaline hydrolysis of four-coordinated phosphorus (PIV) compounds is substantially accelerated if the trigonal-bipyrimidal (TBP) five-coordinated phosphorus (PV) intermediate in the reaction can exhibit conformational transmission.With the compounds 5a-c, it was shown that this acceleration is an entropy effect.Pseudorotation in the PV-TBP intermediate is facilitated if conformational transmission occurs, and therefore the entropy loss during build-up of the PV-TBP is reduced.This evidently results in a lower free energy of activation for the reaction.For the phosphate triester systems 6a and 6b , it was also found that the occurence of conformational transmission speeds up the hydrolysis reaction, although the effect is less pronounced than for the compounds 5a-c.The cyclopentylmethoxy group (6a) and the tetrahydrofurfuryloxy group (6b) show slight preferences for equatorial and axial positioning in the transient PV-TBP, respectively.This study shows for the first time that reaction rate and product selectivity of hydrolyses of phosphate esters can be determined in part by the conformational transmission effect.
- Koole, Leo H.,Olders, Edith A. T. A.,Opresnik, Marko,Buck, Henk M.
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- Free Radicals in Organic Synthesis. A Novel Synthesis of Ethylene Glycol Based on Formaldehyde
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1,3-Dioxolane reacted with formaldehyde in the presence of free radical initiators to produce 2-(hydroxymethyl)-1,3-dioxolane in moderate yield. 2-(Hydroxymethyl)-1,3-dioxolane was catalytically hydrogenated to ethylene glycol.
- Sanderson, John R.,Yeakey, Ernest L.,Lin, Jiang J.,Duranleau, Roger,Marquis, Edward T.
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p. 3243 - 3246
(2007/10/02)
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- Rational Mechanism for Homogeneous Hydrogenation of Carbon Monoxide to Alcohols, Polyols, and Esters
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The products derived from synthesis gas conversion by homogeneous catalysis are concluded to be formed via the key intermediate formaldehyde.The intermediacy of formaldehyde is supported by reaction rate studies, comparison reactions of formaldehyde with synthesis gas, and the trapping of formaldehyde and glycolaldehyde intermediates during a reaction as their ethylene glycol acetals.Although the formation of formaldehyde from synthesis gas is themodynamically unfavorable, it is argued that the concentration of formaldehyde permitted by thermodynamics is more than sufficient for a transient intermediate.The overall mechanism incorporates only step that are already well established in the science of homogeneous catalysis.
- Fahey, Darryl R.
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p. 136 - 141
(2007/10/02)
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