- Selective Oxidation of Secondary Amines to N,N-Disubstituted Hydroxylamines by Choline Peroxydisulfate
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N,N-Disubstituted hydroxylamines were prepared directly from secondary amines by a reliable method using an oxidizing task-specific ionic liquid, choline peroxydisulfate. The operational simplicity, high selectivity, and green reaction conditions, make this method efficient and practical.
- Banan, Alireza,Valizadeh, Hassan,Heydari, Akbar,Moghimi, Abolghasem
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p. 2315 - 2319
(2017/10/06)
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- Synthesis of N,N,O-Trisubstituted Hydroxylamines by Stepwise Reduction and Substitution of O-Acyl N,N-Disubstituted Hydroxylamines
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Diverse N,N,O-trisubstituted hydroxylamines, an under-represented group in compound collections, are readily prepared by partial reduction of N-acyloxy secondary amines with diisobutylaluminum hydride followed by acetylation and reduction of the so-formed O-acyl-N,N-disubstituted hydroxylamines with triethylsilane and boron trifluoride etherate. Use of carbon nucleophiles in the last step, including allyltributylstannane, silyl enol ethers, and 2-methylfuran, gives N,N,O-trisubstituted hydroxylamines with branching α- to the O-substituent. N,N-Disubstiuted hydroxylamines are conveniently prepared by reaction of secondary amines with dibenzoyl peroxide followed by diisobutylaluminum hydride reduction.
- Dhanju, Sandeep,Crich, David
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p. 1820 - 1823
(2016/05/19)
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- PIPERIDINE DERIVATIVE, LIQUID CRYSTAL COMPOSITION AND LIQUID CRYSTAL DISPLAY DEVICE
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To provide a compound having an effect for preventing photolysis of a liquid crystal composition, and having a high solubility in the liquid crystal composition, a liquid crystal composition containing the compound, and a liquid crystal display device including the composition. The compound is represented by formula (1), a liquid crystal composition contains the compound, and a liquid crystal display device includes the composition: [in-line-formulae]M(Z-Q)a(Rb)b??(1)[/in-line-formulae] wherein, in formula (1), a is 1 to 4, and b is a numerical value: (4?a); M is an organic group; Z is a single bond or the like; and Q is a monovalent group represented by formula (Q-1), (Q-2) or (Q-3), in which Ra and Rb are hydrogen, alkyl or the like.
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- Novel gamma secretase inhibitors
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This invention discloses novel gamma secretase inhibitors of the formula: wherein: R1 is a substituted aryl or substituted heteroaryl group; R2 is an R1 group, alkyl, —XC(O)Y, alkylene-XC(O)Y, cycloalkylene-X—C(O)—Y, —CH—X—C(O)—NR3—Y or —CH—X—C(O)—Y, wherein X and Y are as defined herein; each R3 and each R3A are independently H, or alkyl; R11 is aryl, heteroaryl, alkyl, cycloalkyl, arylalkyl, arylcycloalkyl, heteroarylalkyl, heteroarylcycloalkyl, arylheterocycloalkyl, or alkoxyalkyl. Also disclosed is a method of treating Alzheimer's Disease using one or more compounds of the invention.
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- Cyanine dyes
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The invention provides a novel class of cyanine dyes that are functionalized with a linker moiety that facilitates their conjugation to other species. Also provided are conjugates of the dyes, methods of using the dyes and their conjugates and kits including the dyes and their conjugates.
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- Novel gamma secretase inhibitors
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This invention discloses novel gamma secretase inhibitors of the formula: wherein: R1 is a substituted aryl or substituted heteroaryl group; R2 is an R1 group, alkyl, —XC(O)Y, alkylene-XC(O)Y, cycloalkylene-X-C(O)—Y, —CH—X—C(O)—NR3—Y or —CH—X—C(O)—Y, wherein X and Y are as defined herein; each R3 and each R3A are independently H, or alkyl; R11 is aryl, heteroaryl, alkyl, cycloalkyl, arylalkyl, arylcycloalkyl, heteroarylalkyl, heteroarylcycloalkyl, arylheterocycloalkyl, or alkoxyalkyl. Also disclosed is a method of treating Alzheimer's Disease using one or more compounds of the invention.
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- Oxidation-Cope elimination: A REM-resin cleavage protocol for the solid-phase synthesis of hydroxylamines
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We have established that using an oxidation-Cope elimination cleavage protocol allows for the synthesis of N,N-disubstituted hydroxylamines from REM resin (polymer-bound benzyl acrylate). Michael addition of a secondary amine or addition of a primary amine followed by reductive alkylation provides polymer-bound tertiary amines. Oxidation of these resin-bound tertiary amines with MCPBA is followed by concomitant Cope elimination to regenerate the polymer-bound acrylate and provide the cleaved hydroxylamines.
- Sammelson, Robert E,Kurth, Mark J
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p. 3419 - 3422
(2007/10/03)
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- A convenient synthesis of secondary hydroxylamines
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The oxidation of a range of β-cyanoethyl tertiary amines with mCPBA gives the corresponding N-oxides, which can be isolated or undergo Cope-elimination to give secondary hydroxylamines in excellent yield.
- O'Neil, Ian A.,Cleator, Ed,Tapolczay, David J.
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p. 8247 - 8249
(2007/10/03)
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- NEW SYNTHESIS OF (METHOXYCARBONYL)-INDOLIZIDIN-7-ONE AND -QUINOLIZIDIN-2-ONE: AN ACCESS TO β-AMINO ACIDS WITH INDOLIZIDINE AND QUINOLIZIDINE BACKBONE
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Two protected β-amino acids containing the indolizidine or quinolizidine skeleton have been synthesised.The key step of the strategy is represented by the new synthesis of indolizidinone and quinolizidone II carried out by the opening of the tricyclic 1,3-dipolar cycloaddition products 17 or 18 with DABCO.A new and more convenient method for the synthesis of the cyclic hydroxylamines 13 and 14 precursors of nitrones is also reported.
- Cordero, Franca M.,Machetti, Fabrizio,Sarlo, Francesco De,Brandi, Alberto
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- An Evaluation of Hofmann and Cope Elimination Routes to (+/-)-2-n-Propylthietane
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A synthetic route to (+/-)2-n-propylthietane 1 that utilises a silver oxide-induced Hofmann elimination is described together with an evaluation of the potential of a Cope elimination as an alternative and more costeffective route to 1.Some chemistry of the isomeric intermediate thiete sulfones 5 and 12 from each of these respective eliminations is presented.
- Woolhouse, A. D.,Gainsford, G. J.,Crump, D. R.
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p. 873 - 880
(2007/10/02)
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- Preparation of substituted tetrahydropyridines
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A process for preparing certain 1,3,4,4-tetrasubstituted-1,2,3,4-tetrahydropyridines is provided as well as certain 4-carbonate-1,3,4-trisubstituted-piperidines.
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- Unusual reactions of steroidal and non-steroidal 1,5-dioximes. Stereochemistry and mechanism of formation of N-hydroxypiperidine analogues
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4,5-Secocholestane-3,5-dioxime on NaBH4 reduction gave N-hydroxy-3β-methyl-4-aza-5α-cholestane and N-hydroxy-3α-methyl-4-aza-5β-cholestane. The stereochemistry of the products was fully established by converting the N-hydroxy compounds to N-chloro compounds which resulted in 1H nmr signals separating out from the steroid envelope. The dioxime on reaction with NH2OCH3 underwent a regiospecific replacement of the oxime at C-3 by an oxime ether. In both these reactions this and other 1,5 dioximes exhibit unique behaviour not shown by isolated oximes. Arguments are presented pin-pointing a single mechanism involving a "oxadiaza" intermediate isomeric with the dioxime.
- Pradhan, Suresh K.,Akamanchi, Krishnacharya G.,Divakaran, Pulukkunatt P.,Pradhan, Prakash M.
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p. 813 - 839
(2007/10/02)
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- EVOLUTION THERMIQUE DE N-OXYDES D'ω-DIALKYLAMINO ALCANOLS-1
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The thermolysis of ω-dimethylamino-1-alkanol N-oxides affords ω-hydroxy-1-alkenes with dimethylhydroxylamine in good yields.The other basic products (amino alcohol and isoxazolidine) involve oxidation-reduction process between the tertiary amine N-oxide and dimethylhydroxylamine, followed by 1,3-dipolar cycloaddition reaction.Pyrolysis of 5-piperidino-1-pentanol N-oxide proceeds on a path similar to the N-dimethyl compounds.The elimination of an hydrogen atom of the heterocycle does not occur: the preferred planar transition state cannot be attained because of thesteric requirements of the ring.
- Barbry, Didier,Hasiak, Bruno
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p. 2410 - 2414
(2007/10/02)
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