- Direct conversion of phenols into primary anilines with hydrazine catalyzed by palladium
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Primary anilines are essential building blocks to synthesize various pharmaceuticals, agrochemicals, pigments, electronic materials, and others. To date, the syntheses of primary anilines mostly rely on the reduction of nitroarenes or the transition-metal-catalyzed Ullmann, Buchwald-Hartwig and Chan-Lam cross-coupling reactions with ammonia, in which non-renewable petroleum-based chemicals are typically used as feedstocks via multiple step syntheses. A long-standing scientific challenge is to synthesize various primary anilines directly from renewable sources. Herein, we report a general method to directly convert a broad range of phenols into the corresponding primary anilines with the cheap and widely available hydrazine as both amine and hydride sources with simple Pd/C as the catalyst.
- Qiu, Zihang,Lv, Leiyang,Li, Jianbin,Li, Chen-Chen,Li, Chao-Jun
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p. 4775 - 4781
(2019/05/16)
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- Heterogeneous catalytic synthesis of quinoline compounds from aniline and C1-C4 alcohols over zeolite-based catalysts
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The synthesis of quinolines from aniline and a C1-C4 alcohol was conducted under gas-phase reaction conditions over a series of zeolite-based catalysts. The texture and acid properties of catalysts were characterized by XRD, FT-IR, BET and NH3-TPD techniques. It was found that the total yield of quinolines was positively related to the relative content of Lewis acid sites of the catalyst. Among others, the ZnCl2/Ni-USY-acid catalyst possessed the best performance. Over this catalyst, the reactions of aniline and most of the alcohols provided a 42.3-79.7% total yield of quinolones under mild conditions, however, those of aniline and methanol, ethanol and iso-propanol predominantly led to N-alkylanilines. Furthermore, the reaction pathways for synthesizing quinolines via aniline reacting with polyhydric alcohols or monohydric alcohols was proposed in our work.
- Huang, Chen,Li, An,Chao, Zi-Sheng
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p. 48275 - 48285
(2017/10/31)
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- One-pot synthesis of primary amines from carboxylic acids through rearrangement of in situ generated hydroxamic acid derivatives
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A one-pot synthesis of primary amines from carboxylic acids through a Lossen rearrangement of hydroxamic acid derivatives, which were in situ generated by the reaction of carboxylic acids with O-trimethylsilylhydroxylamine (NH2OTMS) and carbonyl diimidazole (CDI, 1.5 equiv) in dimethyl sulfoxide at room temperature, has been achieved. This one-pot method could be applied to various carboxylic acids such as aromatic, heteroaromatic, aliphatic, and optically active substrates.
- Hoshino, Yujiro,Ohtsuka, Naoya,Okada, Takuya,Honda, Kiyoshi
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p. 5304 - 5307
(2016/11/16)
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- Metal Nanoparticles Catalyzed Selective Carbon-Carbon Bond Activation in the Liquid Phase
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Understanding the C-C bond activation mechanism is essential for developing the selective production of hydrocarbons in the petroleum industry and for selective polymer decomposition. In this work, ring-opening reactions of cyclopropane derivatives under hydrogen catalyzed by metal nanoparticles (NPs) in the liquid phase were studied. 40-atom rhodium (Rh) NPs, encapsulated by dendrimer molecules and supported in mesoporous silica, catalyzed the ring opening of cyclopropylbenzene at room temperature under hydrogen in benzene, and the turnover frequency (TOF) was higher than other metals or the Rh homogeneous catalyst counterparts. Comparison of reactants with various substitution groups showed that electron donation on the three-membered ring boosted the TOF of ring opening. The linear products formed with 100% selectivity for ring opening of all reactants catalyzed by the Rh NP. Surface Rh(0) acted as the active site in the NP. The capping agent played an important role in the ring-opening reaction kinetics. Larger particle size tended to show higher TOF and smaller reaction activation energy for Rh NPs encapsulated in either dendrimer or poly(vinylpyrrolidone). The generation/size of dendrimer and surface group also affected the reaction rate and activation energy.
- Ye, Rong,Yuan, Bing,Zhao, Jie,Ralston, Walter T.,Wu, Chung-Yeh,Unel Barin, Ebru,Toste, F. Dean,Somorjai, Gabor A.
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p. 8533 - 8537
(2016/07/26)
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- SUBSTITUTED TRICYCLIC COMPOUNDS WITH ACTIVITY TOWARDS EP1 RECEPTORS
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The present invention belongs to the field of EP1 receptor ligands. More specifically it refers to compounds of general formula (I) having great affinity and selectivity for the EP1 receptor. The invention also refers to the process for their preparation, to their use as medicament for the treatment and/or prophylaxis of diseases or disorders mediated by the EP1 receptor as well as to pharmaceutical compositions comprising them.
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Page/Page column 42
(2013/10/22)
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- Design and synthesis of boronic acid inhibitors of endothelial lipase
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Endothelial lipase (EL) and lipoprotein lipase (LPL) are homologous lipases that act on plasma lipoproteins. EL is predominantly a phospholipase and appears to be a key regulator of plasma HDL-C. LPL is mainly a triglyceride lipase regulating (V)LDL levels. The existing biological data indicate that inhibitors selective for EL over LPL should have anti-atherogenic activity, mainly through increasing plasma HDL-C levels. We report here the synthesis of alkyl, aryl, or acyl-substituted phenylboronic acids that inhibit EL. Many of the inhibitors evaluated proved to be nearly equally potent against both EL and LPL, but several exhibited moderate to good selectivity for EL.
- O'Connell, Daniel P.,Leblanc, Daniel F.,Cromley, Debra,Billheimer, Jeffrey,Rader, Daniel J.,Bachovchin, William W.
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scheme or table
p. 1397 - 1401
(2012/03/26)
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- Homoleptic ruthenium(iii) chalcogenolates: A single precursor to metal chalcogenide nanoparticles catalyst
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Eight homoleptic metal(iii) arylchalcogenolate polymers [M(EPh-p-X) 3]n (M = Ru, Cr, and Mo) were characterized by PXRD. Structural solution of [Ru(SPh-p-tBu)3]n1 was achieved by Rietveld refinement of the PXRD data. Pyrolysis of [Ru(SePh)3] n4 produced nanostructured RuSe2, which selectively catalyzed the reduction of nitro compounds in the presence of other functionalities.
- Chan, Sharon Lai-Fung,Low, Kam-Hung,So, Gary Kwok-Ming,Chui, Stephen Sin-Yin,Che, Chi-Ming
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supporting information; experimental part
p. 8808 - 8810
(2011/10/02)
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- Liquid-crystalline polymorphism of symmetrical azobananas: Bis(4-(4-alkylphenyl)azophenyl) 2-nitroisophtalates
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In this paper we present a series of novel compounds, bis(4-(4-alkylphenyl) azophenyl) 2-nitroisophtalates, which exhibit nematic and banana-type liquidcrystalline phases. The alkyl chain length varies from 1 to 18 carbons. The first ten members of this series exhibit nematic phase. The last eleven compounds exhibit banana-type liquid crystalline phases. The propyl and pentyl derivatives have extra second type of banana mesophase. Copyright Taylor & Francis Group, LLC.
- Zygadlo,Dardas,Nowicka,Hofmann,Galewski
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scheme or table
p. 283 - 291
(2011/08/02)
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- LIQUID CRYSTALLINE PROPERTIES OF 4-CHLOROBENZYLIDENE-4-AKYLANILINES
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A new group of Schiff bases containing a polar terminal group was synthesized: .The alkyl was changed from n=1 to n=12.Based on calorimetric (DSC) studies and on observations of textures the phase situation was characterized.
- Galewski, Zbigniew
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p. 233 - 242
(2007/10/02)
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- Study of the Influence of Molecular Length on the Characteristics of the Ordered Smectic Phase.
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Study of DTA and X-rays of p-phenyl-benzylidene-p'-alkylanilines of mesomorphic phases demonstrates the predominant role of the aliphatic chain length. In effect, it governs the appearance of the different phases; the correlation between layers decreases for greater chain lengths. The nonlinear variations of SmB layer thickness for these compounds shows clearly the importance of steric effects coupled with the molecular length with respect to the dipolar effect.
- Benattar,Levelut,Strzelecki
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p. 1233 - 1240
(2007/10/05)
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