- Direct synthesis of imines from nitro compounds and biomass-derived carbonyl compounds over nitrogen-doped carbon material supported Ni nanoparticles
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The selective synthesis of imines from biomass-derived chemicals over heterogeneous non-noble metal catalysts is of great importance for organic transformation. Herein, non-noble heterogeneous nitrogen-doped carbon supported Ni catalysts (abbreviated as Ni/CN-MgO-T, whereTrepresents the pyrolysis temperature) have been facilely prepared from the simple pyrolysis of Ni precursors and biomass, and Ni/CN-MgO-600 with the smallest size of Ni nanoparticles demonstrated the highest catalytic activity. The reductive coupling of nitroarenes and carbonyl compounds could be performed under mild conditions (80 °C, and 10 bar H2), affording structurally-diverse imines with high to excellent yields (84.2-98.1%). Thanks to the mild reaction conditions, the developed method showed good tolerance to other functional groups such as nitriles, halogen and vinyl groups.
- Li, Bo,Wang, Yanxin,Chi, Quan,Yuan, Ziliang,Liu, Bing,Zhang, Zehui
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p. 4464 - 4471
(2021/03/15)
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- Switchable Imine and Amine Synthesis Catalyzed by a Well-Defined Cobalt Complex
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Switchable imine and amine synthesis catalyzed by a tripodal ligand-supported well-defined cobalt complex is presented herein. A large variety of primary alcohols and amines were selectively converted to imines or amines in good to excellent yields. It is discovered that the base plays a crucial role on the selectivity. A catalytic amount of base leads to the imine formation, while an excess loading of base results in the amine product. This strategy on product selectivity also strongly depends on the organometallic catalysts in use. We expect that the present study could provide useful insights toward selective organic synthesis and catalyst design.
- Paudel, Keshav,Xu, Shi,Hietsoi, Oleksandr,Pandey, Bedraj,Onuh, Chuka,Ding, Keying
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supporting information
p. 418 - 426
(2021/02/01)
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- Method for synthesizing aluminum phosphate molecular sieve catalytic imine
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The invention discloses a method for catalyzing synthesis of an imine by using an aluminum phosphate molecular sieve, and belongs to the technical field of catalytic synthesis of imines. Under the action of an HP-MeAlPO-5 molecular sieve, air or oxygen is used as an oxidant, and an amine and an alcohol which contain different substituents are directly subjected to oxidative coupling to synthesizethe imine under mild conditions. According to the method provided by the invention, the reaction conditions of the adopted catalytic system are mild, and the TOF is high; a reaction can efficiently catalyze the synthesis of the imine at room temperature under air; and the method can adopt transition metals, which are cheap and easy to obtain, such as iron, cobalt and nickel as a molecular sieve dopant, and the availability of the molecular sieve is improved.
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Paragraph 0044-0046
(2020/06/02)
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- Manganese-Catalyzed and Base-Switchable Synthesis of Amines or Imines via Borrowing Hydrogen or Dehydrogenative Condensation
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The use of earth-abundant transition metals as a noble metal replacement in catalysis is especially interesting if different catalytic reactivity is observed. We report, here, on the selective manganese-catalyzed base-switchable synthesis of N-alkylated amines or imines. In both reactions, borrowing hydrogen/hydrogen autotransfer (N-alkyl amine formation) or dehydrogenative condensation (imine formation), we start from the same amines and alcohols and use the same Mn precatalyst. The key is the presence of a potassium base to prefer N-alkylation and a sodium base to permit imine formation. Both bases react with the manganese hydride via deprotonation. The potassium manganate hydride reacts about 40 times faster with an imine to give the corresponding amine than the sodium manganate hydride. The selectivity seems unique for manganese complexes. We observe a broad scope with a complete product overlap, all amine alcohol combinations can be converted into an N-alkyl amine or an imine, and a good functional group tolerance.
- Fertig, Robin,Irrgang, Torsten,Freitag, Frederik,Zander, Judith,Kempe, Rhett
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p. 8525 - 8530
(2018/09/06)
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- Transition metal free catalytic hydroboration of aldehydes and aldimines by amidinato silane
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The transition metal free catalytic hydroboration of aldehydes and ketones is very limited and has not been reported with a well-defined silicon(iv) compound. Therefore, we chose to evaluate the previously reported silicon(iv) hydride [PhC(NtBu)2SiHCl2], (1) as a single component catalyst and found that it catalyzes the reductive hydroboration of a range of aldehydes with pinacolborane (HBpin) under ambient conditions. In addition, compound 1 can catalyze imine hydroboration. DFT calculation was carried out to understand the mechanism.
- Bisai, Milan Kumar,Pahar, Sanjukta,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
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supporting information
p. 2420 - 2424
(2017/03/08)
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- Diastereoselective Synthesis of and Mechanistic Understanding for the Formation of 2-Piperidinones from Imines and Cyano-Substituted Anhydrides
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2-Piperidinones are synthesized in a single step from imines and 2-cyano glutaric anhydrides. The reaction provides the products in good diastereoselectivity and generates a quaternary stereogenic center. Substitutions on the anhydride skeleton are well tolerated to provide 2-piperidinones with three stereogenic centers from a single transformation. The pertinent transition structures have also been computed using quantum mechanics and reveal the key interactions controlling the stereochemical outcome of the reaction.
- Di Maso, Michael J.,Snyder, Kevin M.,De Souza Fernandes, Fábio,Pattawong, Ommidala,Tan, Darlene Q.,Fettinger, James C.,Cheong, Paul Ha-Yeon,Shaw, Jared T.
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supporting information
p. 4794 - 4801
(2016/04/05)
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- Triethylbenzylammonium chloride as a useful and efficient catalyst for the alkylation of indole/substituted indoles in water: A comparative study between conventional and microwave irradiation
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A green and facile method for the alkylation of indole/substituted indole in water using a phase Transfer catalyst (Triethylbenzylammonium Chloride, TEBA) to synthesise bis-indolyl methanes (BIMs) and Michael addition of indole to α,β-unsaturated carbonyl compounds is reported. The substitution of indoles occurred exclusively at the 3-position and products of N-alkylation has not been observed. However, for 3-substituted indoles, reactions were found to occur at the 2-position. A comparative study between conventional heating and microwave irradiation has also been reported. A comparative study between conventional heating and microwave irradiation for the alkylation of indole/substituted indole in water using a phase transfer catalyst (Triethylbenzylammonium Chloride, TEBA) to synthesise bis-indolyl methanes (BIMs) and Michael addition of indole to α, β-unsaturated carbonyl compounds is reported.
- Tumtina, Shokip,Kathing, Chingrishon,Phucho, Ivulho Tovishe,Nongrum, Ridaphun,Myrboh, Bekington,Nongkhlaw, Rishanlang
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p. 321 - 327
(2015/05/20)
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- Ag nanoparticles on mixed Al2O3-Ga2O 3 supports as catalysts for the N-alkylation of amines with alcohols
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The combination of AgNO3 with NaH results in Ag nanoparticles that can selectively perform alcohol aminations under mild reaction conditions (110 C). NaH not only serves as a reducing agent for the Ag salt, but also activates the alcohol for dehydrogenation to the corresponding ketone/aldehyde. The stability of the particles can be improved by immobilizing them onto mixed Al2O3-Ga2O3 supports; the combination of Ga and Al provides materials with stronger Lewis acidic sites compared to pure alumina or gallium oxide supports. This leads to catalysts with enhanced activities, without the necessity of adding external Lewis acids. Detailed TEM characterization also reveals a close interaction between the Ag NPs and the gallium oxide phase. The obtained catalysts are recyclable and show activity for the alcohol amination using a variety of aliphatic and aromatic amines under mild conditions.
- Geukens, Inge,Vermoortele, Frederik,Meledina, Maria,Turner, Stuart,Van Tendeloo, Gustaaf,De Vos, Dirk E.
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p. 373 - 379
(2013/11/19)
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- Bifunctional ruthenium(II) PCP pincer complexes and their catalytic activity in acceptorless dehydrogenative reactions
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New air-stable ruthenium complex 1, bearing the dibenzobarrelene-based cooperating ligand, was synthesized in 96% yield and fully characterized. The examination of its coordination chemistry revealed that the ruthenium center in 1 is slightly distorted from octahedral geometry, and 31P NMR is consistent with the formation of trans-spanned pincer complexes bearing strongly bent dibenzobarrelene-based ligands. The catalytic activity of the new complex was examined in acceptorless dehydrogenation of alcohols and acceptorless dehydrogenative coupling of alcohols with amines.
- Musa, Sanaa,Fronton, Sveta,Vaccaro, Luigi,Gelman, Dmitri
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p. 3069 - 3073
(2013/07/05)
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- NaOH-catalyzed imine synthesis: Aerobic oxidative coupling of alcohols and amines
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The convenient transition-metal-free synthesis of imines through oxidative coupling of alcohols and amines is reported. The reaction is catalyzed by NaOH (10 mol-%) and is performed with air as an oxidant in the absence of any co-solvent. The convenient transition-metal-free synthesis of imines through oxidative coupling of alcohols and amines is reported. The reaction is catalyzed by NaOH (10 mol-%) and is performed with air as an oxidant in the absence of any co-solvent. Copyright
- Donthiri, Ramachandra Reddy,Patil, Rajendra D.,Adimurthy, Subbarayappa
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p. 4457 - 4460
(2012/10/30)
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