- A sterically controlled recyclable system: Reversible photoredox reactions between anthraquinone and hindered tertiary amines
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Photochemical reactions of 9,10-anthraquinone (AQ) with sterically hindered tertiary amines have been studied. The reactivity and products are strongly dependent on the structure of the tertiary amine. Irradiation of AQ in the presence of the sterically hindered amine 1,2,2,6,6-pentamethyl-4-piperidinol (3) (or 1,2,2,6,6-pentamethylpiperidine (5)) in degassed dry benzene leads chiefly to the formation of 9-hydroxy-9-[N-(2,2,6,6-tetramethyl-4-piperidinol)-methyl]anthrone (8), which is found to be metastable at room temperature under vacuum. The reaction may be thermally reversed to regenerate the starting materials. The photolysis products and thermal reversion are solvent dependent. While in dry benzene adduct 8 is the major product, in dry acetonitrile the ionic redox products AQH-and iminium cation are detected and no thermal reversal occurs. The results are explained in terms of equilibrium between a product ion pair (AQH-, iminium+) and a metastable adduct 8. In the presence of water, the reaction leads to the formation of a stable product, 9-hydroxy-9-(hydroxymethyl)anthrone (6). Different reactivity is observed upon irradiation of AQ in the presence of the sterically less hindered tertiary amine trans-tropine (1).
- Gan, Hong,Whitten, David G.
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Read Online
- Synthesis method of 1, 2, 2, 6, 6-pentamethylpiperidinol
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The invention discloses a synthesis method of 1, 2, 2, 6, 6-pentamethylpiperidinol. According to the method, 2, 2, 6, 6-tetramethylpiperidinol and formaldehyde are used as raw materials, and under thecondition of a solid acid catalyst, reflux reaction is performed for 2-8 hours to obtain the product 1, 2, 2, 6, 6-pentamethylpiperidinol. According to the method, 2, 2, 6, 6-tetramethylpiperidinol and formaldehyde are used as initial raw materials, solid acid is used as a catalyst, the catalytic efficiency is high, the operation is simple, the reaction conditions are mild, the selectivity and yield of the product are relatively high, and the method has a wide industrial application prospect.
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Paragraph 0025-0030
(2020/01/25)
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- Synthetic method of light stabilizer intermediate of 1,2,2,6,6-pentamethyl-4-pipradrol
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The invention provides a synthetic method of a light stabilizer intermediate of 1,2,2,6,6-pentamethyl-4-pipradrol, and particularly relates to the technical field of light stabilizer preparation. Themethod comprises two step reactions; in the first step, 2,2,6,6-tetramethyl-4-pipradrol and paraformaldehyde are mixed according to a certain proportion and are added into a solvent; stirring is performed for a certain time at the ordinary pressure and a certain reaction temperature, so that the 2,2,6,6-tetramethyl-4-pipradrol completely reacts; then, cooling is performed to reach room temperature; filtering is performed to remove excessive paraformaldehyde; a hydroxymethylated product is obtained; in the second step, a reduction type solid catalyst is charged into a fixed bed reactor; the solvent is added into the reaction liquid; the mixture is continuously introduced into the fixed bed reactor at a certain feeding speed; hydrogen gas is introduced; heating is performed; the reaction liquid continuously flows out from the lower end of the fixed bed reactor; flowing-out reaction liquid is subjected to cooling, gas-liquid separation, liquid filtering, filter liquid solvent steaming removal and purification; the target product is obtained. The synthetic method has the advantages that the preparation is simple and convenient; economic performance and environment-friendly effects areachieved; the product quality is high; the yield is high; the method is suitable for industrial production.
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Paragraph 0034; 0035; 0041; 0047; 0053; 0064; 0071; 0077
(2018/03/26)
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- PROCESS FOR PREPARING AN N-METHYL-SUBSTITUTED TRIACETONAMINE COMPOUND
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An N-methyl-substituted triacetonamine compound is prepared by reacting at least one triacetonamine compound (I) with formaldehyde under reductive conditions, in the presence of hydrogen and in the presence of a supported catalyst, wherein the supported catalyst contains at least one metal M, wherein the metal M is selected from the group consisting of V, Cr, Mo, Mn, Ni, Pd, Pt, Fe, Ru, Os, Co, Rh, Ir, and Cu.
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Paragraph 0558-0561
(2016/08/17)
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- N-Methylation of amine and nitro compounds with CO2/H2 catalyzed by Pd/CuZrOx under mild reaction conditions
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An active Pd/ZrCuOx catalyst was prepared for the reductive amination of CO2. The N-methylation of amines and nitro compounds with CO2/H2 can be realized with up to 97% yield under relatively mild reaction condi
- Cui, Xinjiang,Zhang, Yan,Deng, Youquan,Shi, Feng
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supporting information
p. 13521 - 13524
(2015/01/09)
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- MODIFIED ZNO NANOPARTICLES
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Process for the preparation of modified zinc oxide nanoparticles, which comprises reacting zinc oxide nanoparticles, which are dissolved in a solvent, in the presence of ammonia or amines with a tetraalkyl orthosilicate and optionally with an organosilane, with the proviso that the reaction takes place at a content of less than 5% by weight of water, based on the total amount of solvent and water. Modified zinc oxide nanoparticles which have Si—O-alkyl groups and are soluble in organic solvents, obtainable by this process for the preparation. Liquid or solid formulations which comprise modified ZnO nanoparticles. Inanimate organic materials, for example plastics or coatings, which comprise modified ZnO nanoparticles. Method of stabilizing inanimate organic materials against the effect of light, free radicals or heat, where modified ZnO nanoparticles, which optionally comprise UV absorbers and/or stabilizers as further additives, are added to the materials.
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- Suppression of spin-spin coupling in nitroxyl biradicals by supramolecular host-guest interactions
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The use of supramolecular architectures to control the spatially dependent spin exchange (spin communication) between two covalently linked radical centers (biradical) has been explored. Cucurbit[8]uril, through supramolecular steric effect, completely suppresses spin exchange between two adjacent radical centers in a biradical. The Royal Society of Chemistry.
- Porel, Mintu,Ottaviani, M. Francesca,Jockusch, Steffen,Jayaraj, Nithyanandhan,Turro, Nicholas J.,Ramamurthy
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supporting information; experimental part
p. 7736 - 7738
(2010/11/17)
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- NPY ANTAGONISTS, PREPARATION AND USES
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The present invention concerns novel compounds, their preparation and their uses, therapeutic uses in particular. More specifically it concerns derivative compounds having at least two aromatic cycles, their preparation and their uses, in particular in the area of human or animal health. These compounds have an affinity for the biological receptors of neuropeptide Y, NPY, present in the central and peripheral nervous systems. The compounds of the invention are preferably NPY antagonists, and more particularly antagonists of sub-type NPY Y1, and can therefore be used for the therapeutic or prophylactic treatment of any disorder involving NPY. The present invention also concerns pharmaceutical compositions containing said compounds, their preparation and their uses, as well as treatment methods using said compounds.
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Page/Page column 65
(2009/09/28)
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- Novel vinylic hindered amine light stabilizers
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Vinylic hindered amine light stabilizers as novel polylmerizable light stabilizers are disclosed and have the general formula (I): wherein: R1 is C1to C8: alkyl, alkoxy, alkyl phenyl, hydroxy alkyl (all linear and branched), ally, acyl, cycloalkyl (cyclopentyl, cyclohexyl or cumyl: linear and branched); R2 is hydrogen and methyl, R3 is vinyl, C1-C4 vinyl alkyl [H2C═C(R4)C1-C4]; R4 is H, C1-C4 alkyl and alkyl phenyl and R5 is H, C1-C4 alkyl, X is 0, NH, C1-C8 alkyloxy and alkylamino: (linear or branched).
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- Piperidyl organosiloxanes and polymer substrates light-stabilized therewith
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Novel piperidyl organosiloxanes, well adapted for the light/UV-stabilization of a wide variety of polymer substrates, e.g., polyolefins and polyalkadienes, have the structural formula (I): STR1
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- Interaction of tert-Butylcalixarenes with Cyclic Amines
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p-tert Butylcalixarenes 1 and 2 react with the cyclic amines 3 - 8, 10 by proton transfer forming so -called "exo-complexes" between the ammonium and phenolate groups.As well endocyclic as exocyclic amino groups are reactive.The nitroxyl radical 9 does not react with 1 or 2 by the proton transfer reaction.These results demonstrate that an interaction between the nitrogen atom of HALS-compounds, esp. compound 10, with calixarene hydroxylgroups is possible, but an interaction between the corresponding nitroxyl radicals with calixarene hydroxylgroups does not occur.
- Goermar, Gerhard,Seiffarth, Klaus,Schulz, Manfred,Chachimbombo, Chitula Leopoldina
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p. 475 - 479
(2007/10/02)
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- Bicyclo 4-acyloxypiperidine light stabilizers
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A 4-acyloxypiperidine of the formula I STR1 in which R1 denotes C1 -C30 -alkyl, C3 -C20 -alkenyl, C3 -C20 -alkynyl, C2 -C30 -cyanoalkyl, C2 -C30 -alkoxyalkyl, C7 -C20 -aralkyl, 2,3-epoxypropyl, an aliphatic, alicyclic, aromatic, araliphatic or heterocyclic acyl group with 1-20 C atoms or one of the groups --CH2 COOR4, --CH2 -CH(R5)--OR6, --COOR7 or --CONHR7, in which R4 is C1 -C12 -alkyl, C3 -C6 -alkenyl, phenyl, C7 -C8 -aralkyl or cyclohexyl and R5 is hydrogen, methyl or phenyl and R6 denotes hydrogen or an aliphatic or aromatic, araliphatic or alicyclic acyl group with 1-18 C atoms, in which the aromatic part can optionally be substituted by chlorine, C1 -C4 -alkyl or C1 -C8 -alkoxy and/or by hydroxyl, and R7 denotes C1 -C12 -alkyl, cyclohexyl, phenyl or benzyl, R2 is hydrogen or C1 -C8 -alkyl, R3 is C1 -C30 -alkyl, C1 -C30 -hydroxyalkyl, C2 -C30 -cyanoalkyl, C2 -C30 -alkoxyalkyl, C3 -C30 -alkoxycarbonylalkyl, C3 -C20 -alkenyl, C3 -C20 -alkynyl, C3 -C12 -cycloalkyl, C6 -C15 -aryl or C7 -C20 -aralkyl, Z is a monovalent to tetravalent 6-membered cycloaliphatic radical with a C1 -C2 bridge member, e is 1-4, m is 0-3 and e+m is 1-4, as stabilizers for organic material.
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- Substituted piperidin-4-ols
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Disclosed are stabilized compositions comprising a polymer, especially polyolefines, and a minor proportion of a 1,2,2,6,6-pentasubstituted piperidin-4-ol. The new compositions possess good light stability.
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