- Utilization of a Hydrogen Source from Renewable Lignocellulosic Biomass for Hydrogenation of Nitroarenes
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Exploring of hydrogen source from renewable biomass, such as glucose in alkaline solution, for hydrogenation reactions had been studied since 1860s. According to proposed pathway, only small part of hydrogen source in glucose was utilized. Herein, the utilization of a hydrogen source from renewable lignocellulosic biomass, one of the most abundant renewable sources in nature, for a hydrogenation reaction is described. The hydrogenation is demonstrated by reduction of nitroarenes to arylamines in up to 95 % yields. Mechanism studies suggest that the hydrogenation occurs via a hydrogen transformation pathway.
- Tan, Fang-Fang,Tang, Kai-Li,Zhang, Ping,Guo, Yan-Jun,Qu, Mengnan,Li, Yang
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p. 4189 - 4195
(2019/03/07)
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- 3-(5-CHLORO-2-OXOBENZO[D]OXAZOL-3(2H)-YL)PROPANOIC ACID DERIVATIVES AS KMO INHIBITORS
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A compound of formula (I) or a salt thereof are provided wherein R1, X and R3 are defined in the specification, useful in the treatment of disorders mediated by KMO such as acute pancreatitis, chronic kidney disease, other conditions associated with systemic inflammatory response syndrome (SIRS), Huntington's disease, Alzheimer's disease, spinocerebellar ataxias, Parkinson's disease, AIDS-dementia complex, amylotrophic lateral sclerosis (ALS), depression, schizophrenia, sepsis, cardiovascular shock, severe trauma, acute lung injury, acute respiratory distress syndrome, acute cholecystitis, severe burns, pneumonia, extensive surgical procedures, ischemic bowel, severe acute hepatic disease, severe acute hepatic encephalopathy or acute renal failure.
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- Highly selective transfer hydrogenation of functionalised nitroarenes using cobalt-based nanocatalysts
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Anilines are important feedstock for the synthesis of a variety of chemicals such as dyes, pigments, pharmaceuticals and agrochemicals. The chemoselective catalytic reduction of nitro compounds represents the most important and prevalent process for the manufacture of functionalized anilines. Consequently, the development of selective catalysts for the reduction of nitro compounds in the presence of other reducible groups is a major challenge and is crucial. In this regard, herein we show that the cobalt oxide (Co3O4-NGr@C) based nano-materials, prepared by the pyrolysis of cobalt-phenanthroline complexes on carbon constitute highly selective catalysts for the transfer hydrogenation of nitroarenes to anilines using formic acid as a hydrogen source. Applying these catalysts, a series of structurally diverse and functionalized nitroarenes have been reduced to anilines with unprecedented chemo-selectivity tolerating halides, olefins, aldehyde, ketone, ester, amide and nitrile functionalities.
- Jagadeesh, Rajenahally V.,Banerjee, Debasis,Arockiam, Percia Beatrice,Junge, Henrik,Junge, Kathrin,Pohl, Marga-Martina,Radnik, J?rg,Brückner, Angelika,Beller, Matthias
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supporting information
p. 898 - 902
(2015/03/04)
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- Nanoscale Fe2O3-based catalysts for selective hydrogenation of nitroarenes to anilines
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Production of anilines - key intermediates for the fine chemical, agrochemical, and pharmaceutical industries - relies on precious metal catalysts that selectively hydrogenate aryl nitro groups in the presence of other easily reducible functionalities. Herein, we report convenient and stable iron oxide (Fe2O3) - based catalysts as a more earth-abundant alternative for this transformation. Pyrolysis of iron-phenanthroline complexes on carbon furnishes a unique structure in which the active Fe2O 3 particles are surrounded by a nitrogen-doped carbon layer. Highly selective hydrogenation of numerous structurally diverse nitroarenes (more than 80 examples) proceeded in good to excellent yield under industrially viable conditions.
- Jagadeesh, Rajenahally V.,Surkus, Annette-Enrica,Junge, Henrik,Pohl, Marga-Martina,Radnik, Joerg,Rabeah, Jabor,Huan, Heming,Schunemann, Volker,Brueckner, Angelika,Beller, Matthias
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p. 1073 - 1076
(2014/01/06)
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- A new class of heterogeneous platinum catalysts for the chemoselective hydrogenation of nitroarenes
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A new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum-Hydrogel.
- Pandarus, Valerica,Ciriminna, Rosaria,Beland, Francois,Pagliaro, Mario
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scheme or table
p. 1306 - 1316
(2011/06/25)
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- HIGH-PURITY NAPHTHOL AS PIGMENTS
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Naphthol AS pigments of formula (IV) have a maximum content of the secondary components (1) to (5) defined by the following upper limits (see the table).
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Page/Page column 15-18
(2010/02/14)
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- SUBSTITUTED QUINAZOLINE DERIVATIVES AND THEIR USE AS INHIBITORS
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The use of a compound of formula (I) 1 or a salt, ester or amide thereof; where X is O, or S, S(O) or S(O)2, or NR6 where R6 is hydrogen or C1-6 alkyl,; R5 is an optionally substituted 5-membered heteroaromatic ring, R1, R2 ,R3, R4 are independently selected from various specified moieties, in the preparation of a medicament for use in the inhibition of aurora 2 kinase. Certain compounds are novel and these, together with pharmaceutical compositions containing them are also described and claimed
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- Pharmacologically active pyridine derivatives and processes for the preparation thereof
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N-phenyl-2-pyrimidineamine derivatives of formula I STR1 wherein the substituents are as defined in claim 1 and the derivatives of formula I can be used, for example, in the treatment of tumour diseases.
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- Cyclization-Activated Prodrugs: N-(Substituted 2-hydroxyphenyl and 2-hydroxypropyl)carbamates Based on Ring-Opened Derivatives of Active Benzoxazolones and Oxazolidinones as Mutual Prodrugs of Acetaminophen
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N-(Substituted 2-hydroxyphenyl)- and N-(substituted 2-hydroxypropyl)carbamates based on masked active benzoxazolones (model A) and oxazolidinones (model B), respectively, were synthesized and evaluated as potential drug delivery systems.A series of alkyl and aryl N-(5-chloro-2-hydroxyphenyl)carbamates 1 related to model A was prepared.These are open drugs of the skeletal muscle relaxant chlorzoxazone.The corresponding 4-acetamidophenyl ester named chloracetamol is a mutual prodrug of chloroxazone and acetaminophen.Chlorzacetamol and two other mutual prodrugs of active bezoxazolones and acetaminophen were obtained in a two-step process via condensation of 4-acetamidophenyl 1,2,2,2-tetrachloroethyl carbonate with the appropiate anilines.Based on model B, two mutual prodrugs of acetaminophen and active oxazolidinones (metaxalone and mephenoxalone) were similarly obtained using the appropiate amines.All the carbamate prodrugs prepared were found to release the parent drugs in aqueous (pH 6-11) and plasma (pH 7.4) media.The detailed mechanistic study of prodrugs 1 carried out in aqueous medium at 37 deg C shows a change in the Broensted-type relationship log t1/2 vs pKa of the leaving groups ROH: log t1/2 = 0.46pKa - 3.55 for aryl and trihalogenoethyl esters and log t1/2 = 1.46pKa - 16.03 for alkyl esters.This change is consistent with a cyclization mechanism involving a change in the rate-limiting step from formation of a cyclic tetrahedral intermediate (step k1) to departure of the leaving group ROH (step k2) when the leaving group ability decreases.This mechanism occurs for all the prodrugs related to model A.Regeneration of the parent drugs from mutual prodrugs related to model B takes place by means of a rate-limiting elimination-addition reaction (E1cB mechanism).This affords acetaminophen and the corresponding 2-hydroxypropyl isocyanate intermediates which cyclize at any pH to the corresponding oxazolidinone drugs.As opposed to model A, the rates of hydrolysis of mutual prodrugs of model B clearly exhibit a catalytic role of the plasma.It is concluded from the plasma studies that the carbamate substrates can be enzymatically transformed into potent electrophiles, i.e., isocyanates.In the case of the present study, the prodrugs are 2-hydroxycarbamates for which the propinquity of the hydroxyl residue and the isocyanate group enforces a cyclization reaction.This mechanistic particularity precludes their potential toxicity in terms of potent electrophiles capable of modifying critical macromolecules.
- Vigroux, Alain,Bergon, Michel,Zedde, Chantal
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p. 3983 - 3994
(2007/10/03)
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- Hypervalent iodine-induced nucleophilic substitution of para-substituted phenol ethers. Generation of cation radicals as reactive intermediates
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A novel hypervalent iodine induced nucleophilic substitution of para-substituted phenol ethers in the presence of a variety of nucleophiles is described. UV and ESR spectroscopic studies indicate that this reaction proceeds via cation radicals, [ArH?+], as reactive intermediates generated by single-electron transfer (SET) from a charge-transfer (CT) complex of phenol ethers with phenyliodine(III) bis(trifluoroacetate) (PIFA). This is the first case that involves a radical intermediate on hypervalent iodine oxidations of aromatic compounds.
- Kita, Yasuyuki,Tohma, Hirofumi,Hatanaka, Kenji,Takada, Takeshi,Fujita, Shigekazu,Mitoh, Shizue,Sakurai, Hiromu,Oka, Shigenori
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p. 3684 - 3691
(2007/10/02)
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- Azo reactive dyestuffs having an aryl-triazinyl-aryl diazo component
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Optionally metallized azo dyestuffs which in the form of the free acid correspond to the formula STR1 wherein K is the radical of a benzene, naphthalene, pyrazolone, pyridone, pyrimidone, acetoacetic acid arylide or aminopyrazole coupling component; A is a non-ionic substituent; X is STR2 wherein W is a direct bond or a bridge member to a C atom of the benzene or naphthalene nucleus or the coupling component K; R is hydrogen or C1 -C4 -alkyl; B is a direct bond or a bridge member, especially -CO- or -SO2 -, to a C atom of Q; Q is a reactive radical; m is 0, 1 or 2; n is 0, 1 or 2; p is 0 or 1; q is 0, 1 or 2; and r is 0 or 1; and their use for the dyeing and printing of natural and regenerated cellulose fibre materials such as cotton and rayon, as well as natural and synthetic polyamide fibre materials, for example those of wool, silk, poly-ε-caprolactam or polycondensate of hexamethylene-diamine and adipic acid. The dyeings obtained, espeically those on cotton and rayon, are distinguished by good fastness properties, especially fastness to wet processing and to light.
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- Process for preparing 3-chloro- and 3,5-dichloro-anilines
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Analines, meta-substituted by chlorine are prepared by reacting chloro-anilines having the formula STR1 wherein X1 and X2 are the same or different and represent chlorine, hydrogen or optionally substituted alkyl, aryl, aralkyl, alkoxy or aralkoxy, with one of the radicals X1 or X2 representing chlorine when 3-chloroanilines are being prepared and X1 and X2 representing chlorine when 3,5-dichloroanilines are being prepared and R1, R2 and R3 are the same or different and represent chlorine, hydrogen or optionally substituted alkyl, aryl, aralkyl, alkoxy or aralkoxy, with at least one of the radicals R1, R2 or R3 representing chlorine with hydrogen in solution in a neutral or acid medium in the presence of noble metals which are in the elementary form or in the form of compounds and are optionally applied to supports, and in the presence of sulfur or sulfur compounds at elevated temperatures and under pressure.
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- Biphenyloxy derivatives and antihyperlipidemic use
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Compounds of the formula STR1 wherein R1 is straight or branched alkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 6 carbon atoms, phenylalkyl, phenylalkenyl, pyridyl or STR2 where X, Y and Z are each hydrogen, halogen, alkyl of 1 to 3 carbon atoms or alkoxy of 1 to 3 carbon atoms, R2 is hydrogen or alkyl of 1 to 4 carbon atoms, R3 is hydroxymethyl, carboxyl, alkoxycarbonyl of 2 to 7 carbon atoms or cycloalkoxycarbonyl or 4 to 8 carbon atoms, A is --CO--NH-- or --NH--CO--, and n is 1, 2 or 3, And, when R3 is carboxyl, non-toxic salts thereof formed with an inorganic or organic base; the compounds as well as the salts are useful as antihyperlipidemics.
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