- Nucleophilic Aromatic Substitution Reactions in Water Enabled by Micellar Catalysis
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Given the huge dependence on dipolar, aprotic solvents such as DMF, DMSO, DMAc, and NMP in nucleophilic aromatic substitution reactions (SNAr), a simple and environmentally friendly alternative is reported. Use of a "benign-by-design" nonionic surfactant, TPGS-750-M, in water enables nitrogen, oxygen, and sulfur nucleophiles to participate in SNAr reactions. Aromatic and heteroaromatic substrates readily participate in this micellar catalysis, which takes place at or near ambient temperatures.
- Isley, Nicholas A.,Linstadt, Roscoe T. H.,Kelly, Sean M.,Gallou, Fabrice,Lipshutz, Bruce H.
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- Heterostructured Hybrid rGO@α-MnO2/rGO@δ-MnO2 Nanoflower: An Efficient Catalyst for Aerobic Solvent-Free N-Alkylation Reactions and Energy Storage Material
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A new reduced graphene oxide (rGO) based bi-phasic crystal of MnO2, namely α-MnO2 nanorods and δ-MnO2 nanoflakes containing heterostructured hybrid nanoflower rGO@α-MnO2/rGO@δ-MnO2 has been fabricated through a facile hydrothermal method followed by annealing treatment. The successful synthesis of the hybrid material was studied by XRD, Raman, BET, FESEM with EDX, FTIR and TEM analyses. An efficient N-alkylation reaction of substituted aromatic amines with aromatic alcohols was carried out under solvent-free aerobic conditions in the presence of catalytic amount of rGO@α-MnO2/rGO@δ-MnO2. The catalyst shows excellent activity in terms of high yields (up to 98 %), short reaction time (10 h) along with a simple work-up process. The spent material can be regenerated several times without causing any serious decrease in catalytic activity. Moreover, cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and cyclic stability techniques were executed to evaluate the performances of rGO@α-MnO2, rGO@δ-MnO2, and rGO@α-MnO2/rGO@δ-MnO2 as energy storage materials. Among all those materials, rGO@α-MnO2/rGO@δ-MnO2 exhibited a proficient specific capacitance, CS (267 F/g at 1 A/g) along with excellent cycling ability (～83 % retention up to 10000 cycles). The superb electrochemical performance of rGO@α-MnO2/rGO@δ-MnO2 might be ascribed to the combination of bi-phasic α-MnO2 and δ-MnO2 with rGO sheets, resulting in a flower-like structure.
- Chaudhuri, Haribandhu,Karak, Niranjan
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- BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
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A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
- Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
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supporting information
p. 5205 - 5211
(2021/07/29)
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- Trimethyl Borate-Catalyzed, Solvent-Free Reductive Amination
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Solvent-free reductive amination of aldehydes and ketones with aliphatic and aromatic amines in high-to-excellent yields has been achieved with sub-stoichiometric trimethyl borate as promoter and ammonia borane as reductant.
- Ramachandran, P. Veeraraghavan,Choudhary, Shivani,Singh, Aman
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p. 4274 - 4280
(2021/03/09)
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- Nucleophilic aromatic substitution reactions under aqueous, mild conditions using polymeric additive HPMC
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The use of the inexpensive, benign, and sustainable polymer, hydroxypropyl methylcellulose (HPMC), in water enables nucleophilic aromatic subsitution (SNAr) reactions between various nucleophiles and electrophiles. The mild reaction conditions facilitate a broad functional group tolerance that can be utilized for subsequent derivatization for the synthesis of pharmaceutically relevant building blocks. The use of only equimolar amounts of all reagents and water as reaction solvent reveals the greenness and sustainability of the methodology presented herein.
- Ansari, Tharique N.,Borlinghaus, Niginia,Braje, Leon H.,Braje, Wilfried M.,Handa, Sachin,Ogulu, Deborah,Wittmann, Valentin
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supporting information
p. 3955 - 3962
(2021/06/17)
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- Nickel?Copper bimetallic mesoporous nanoparticles: As an efficient heterogeneous catalyst for N-alkylation of amines with alcohols
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A bimetallic catalyst (Ni/Cu-MCM-41) is prepared via co-condensation method. The latter is characterized by Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), diffuse reflectance spectroscopy (DRS), and nitrogen adsorption–desorption analysis. Catalytic performance of Ni/Cu-MCM-41 is probed in N-alkylation of amines with alcohols through a hydrogen autotransfer process. Noteworthy, this catalytic system appears very efficient for synthesis of a range of secondary and tertiary amines in good to excellent isolated yields. Moreover, the catalyst is successfully recovered and reused four times without notable decrease in its activity.
- Nasresfahani, Zahra,Kassaee, Mohamad Z.
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- Rate and Yield Enhancements in Nucleophilic Aromatic Substitution Reactions via Mechanochemistry
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A variety of nucleophilic aromatic substitution reactions were carried out mechanochemically to great advantage. On average, reactions rates were nine-times faster. The corresponding kinetic studies presented provide the clearest head-to-head kinetic comparisons between mechanochemical and conventional systems at identical temperatures. Attempts are provided at classifying the kinetics of one example. Removal of polar, protic solvents from these reactions presents environmental benefits to a reaction class whose kinetics are heavily dependent on such solvents.
- Andersen, Joel M.,Starbuck, Hunter F.
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p. 13983 - 13989
(2021/04/02)
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- Iron-Catalyzed Oxidative Amination of Benzylic C(sp3)–H Bonds with Anilines
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Iron-catalyzed oxidative amination of benzylic C(sp3)–H bonds with anilines bearing electron-withdrawing groups (EWGs) or electron-donating groups (EDGs) is realized based on simple variations of N-substituents on imidazolium cations in novel ionic Fe(III) complexes. The structural modification of the imidazolium cation resulted in regulation of the redox potential and the catalytic performance of the iron metal center. Using DTBP as oxidant, [HItBu][FeBr4] showed the highest catalytic activity for anilines bearing EWGs, while [HIPym][FeBr4] was more efficient for EDG-substituted anilines. This work provides alternative access to benzylamines with the advantages of both a wide substrate scope and iron catalysis.
- Song, Yan-Ling,Li, Bei,Xie, Zhen-Biao,Wang, Dan,Sun, Hong-Mei
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p. 17975 - 17985
(2021/12/13)
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- Catalyst- And solvent-free efficient access to: N -alkylated amines via reductive amination using HBpin
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A sustainable approach which works under catalyst- and solvent-free conditions for the synthesis of structurally diverse secondary amines has been uncovered. This one-pot protocol works efficiently at room temperature and is compatible with a wide range of sterically and electronically diverse aldehydes and primary amines. Notably, this simple process offers scalability, excellent functional group tolerance, chemoselectivity, and is also effective at the synthesis of biologically relevant molecules. This journal is
- Bauri, Somnath,Pandey, Vipin K.,Rit, Arnab
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p. 3853 - 3857
(2020/07/27)
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- Cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ
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A cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ is reported, which uses nonmetallic quinone DDQ as an oxidant in the allylation of N-benzylanilines under mild conditions. C–C bond with high selectivity and activity was constructed in this reaction and homoallylic amines were obtained with yields of up to 99%.
- Xiong, Ruimei,Hussain, Muhammad Ijaz,Liu, Qing,Xia, Wen,Xiong, Yan
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supporting information
(2019/12/11)
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- Scalable preparation of stable and reusable silica supported palladium nanoparticles as catalysts for N-alkylation of amines with alcohols
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The development of nanoparticles-based heterogeneous catalysts continues to be of scientific and industrial interest for the advancement of sustainable chemical processes. Notably, up-scaling the production of catalysts to sustain unique structural features, activities and selectivities is highly important and remains challenging. Herein, we report the expedient synthesis of Pd-nanoparticles as amination catalysts by the reduction of simple palladium salt on commercial silica using molecular hydrogen. The resulting Pd-nanoparticles constitute stable and reusable catalysts for the synthesis of various N-alkyl amines using borrowing hydrogen technology without the use of any base or additive. By applying this Pd-based catalyst, functionalized and structurally diverse N-alkylated amines as well as some selected drug molecules were synthesized in good to excellent yields. Practical and synthetic utility of this Pd-based amination protocol has been demonstrated by upscaling catalyst preparation and amination reactions to several grams-scales as well as recycling of catalyst. Noteworthy, this Pd-catalyst preparation has been up-scaled to kilogram scale and catalysts prepared in both small (1 g) and large-scale (kg) exhibited similar structural features and activity.
- Alshammari, Ahmad S.,Natte, Kishore,Kalevaru, Narayana V.,Bagabas, Abdulaziz,Jagadeesh, Rajenahally V.
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p. 141 - 149
(2020/01/06)
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- Ru(II) complexes containing (2-(pyren-1-ylmethylene)hydrazinyl)benzothiazole: Synthesis, solid-state structure, computational study and catalysis in N-alkylation reactions
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Reactions of (2-(pyren-1-ylmethylene)hydrazinyl)benzothiazole (L) with ruthenium(II) prefabricated precursors [RuHCl(CO)(EPh3)3] and [RuH2(CO)(EPh3)3] (E = P or As) afforded new Ru(II) complexes [RuCl(CO)(EPh3)2(L)] and [RuH(CO)(EPh3)2(L)] (E = P or As) (1–4). All the Ru(II) complexes (1–4) were characterized by IR, NMR spectroscopies, ESI-mass spectrometry and elemental analyses. The solid-state structures of Ru(II) complexes (2 and 3) were established by single crystal X-ray analyses and revealed distorted octahedral geometries around the ruthenium(II) ion and mono anionic bidentate N^N coordination mode for hydrazine ligand. The Ru(II) complexes 2 and 3 were also analyzed using Hirshfeld surface analysis and DFT calculations. Moreover, all the complexes (1–4) were utilized in the N-alkylation reactions of amines using alcohol. Complex 3 was found to be highly active towards N-alkylation of different aromatic amines with alcohol.
- Murugan, Kaliyappan,Ojwach, Stephen O.,Saravanan, Kandasamy,Vijayan, Paranthaman,Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
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- In water alkylation of amines with alcohols through a borrowing hydrogen process catalysed by ruthenium nanoparticles
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A simple and environmentally benign procedure for the synthesis of secondary amines in water has been developed. Combining Ru3(CO)12, tetraphenylcyclopentadienone and a small quantity of TGPS-750-M surfactant, primary and secondary alcohols were alkylated at N employing equimolar amounts of aromatic amines in water. The reaction occurs under microwave (MW) dielectric heating with high conversion and high yield. When required, the use of biomass-derived 2-MeTHF or GVL as a co-solvent is possible. Under the influence of MWs, a Ru nanoparticle-nanomicelle combination was formed acting as an effective and recyclable catalyst. This protocol was also employed for "in water" cyclisation to synthesise biologically relevant pyrrolobenzodiazepines (PBDs).
- Risi, Caterina,Calamante, Massimo,Cini, Elena,Faltoni, Valentina,Petricci, Elena,Rosati, Filippo,Taddei, Maurizio
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supporting information
p. 327 - 331
(2020/02/13)
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- Borrowing hydrogen activity of NH2-MIL-125 for N-alkylation of amines with alcohols under solvent and base free condition
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The NH2-MIL-125 showed excellent activity in solvent and base free N-alkylation of amines with alcohols via borrowing hydrogen mechanism. The Ti–O clusters of NH2-MIL-125 provide acidic-basic active sites for the catalysis of reaction. The NH2-MIL-125 was found to be stable and reusable in the reaction.
- Mishra, Manish Kumar,Neogi, Subhadip,Patel, Nisha B.,Shukla, Atindra,Vala, Naresh
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- Cp*Co(iii) and Cu(OAc)2bimetallic catalysis for Buchwald-type C-N cross coupling of aryl chlorides and amines under base, inert gas & solvent-free conditions
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A strategy involving bimetallic catalysis with a combination of Cp?Co(CO)I2 and Cu(OAc)2 was used for performing Buchwald-type C-N coupling reactions of aryl chlorides with amines. The reactions proceeded at 100 °C to produce excellent yields of many of the desired C-N coupled products, in 4 h, under aerobic reaction conditions. The reactions were shown to run under base-free and solvent-free conditions, enabling this strategy to work efficiently for electron-withdrawing and base-sensitive functionalities. The presented methodology was found to be equally efficient for electron-donating functionalities as well as for primary (1°) and secondary (2°) aromatic and aliphatic amines. Moreover, the products were easily separated through the extractions of the organic aqueous layer, with this process chromatographic separations is not required.
- Srivastava, Avinash K.,Sharma, Charu,Joshi, Raj K.
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supporting information
p. 8248 - 8253
(2020/12/29)
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- Half-sandwich (η5-Cp?)Rh(iii) complexes of pyrazolated organo-sulfur/selenium/tellurium ligands: Efficient catalysts for base/solvent free C-N coupling of chloroarenes under aerobic conditions
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Three new pyrazolated chalcogenoether ligated Rh(iii) half-sandwich complexes (1-3) were synthesised by the thermal reaction of chalcogenoether (S, Se and Te) substituted 1H-pyrazole ligands (L1-L3) and [(η5-C5Me5)RhCl]2 in methanol. The complexes were fully characterised by various spectroscopic techniques, and the molecular structures of complexes 1 and2 were also established through single crystal X-ray crystallographic analysis, which indicates a pseudo-octahedral half-sandwich piano-stool geometry around the rhodium metal. All three complexes were found to be thermally stable and insensitive towards air and moisture. One mol% of Rh(iii) complexes (1-3) along with 10 mol% of Cu(OAc)2 were explored for the Buchwald-Hartwig type C-N coupling reactions of amine and aryl chloride. Good to excellent yields (89-92%) of the coupling products were obtained with seleno- and thio-ether functionalised pyrazolated Rh(iii) complexes (1 and 2), while an average yield (39%) was obtained with the telluro-ether functionalised complex (3). In contrast to the previously reported C-N coupling reactions the present reaction works under solvent- and base-free conditions, and the coupling reaction is accomplished in just 6 h with a high yield of the coupling product. The present methodology was also found to be efficient for a wide variety of functionalised aryl halides, and aliphatic or aromatic amines (1° and 2°). Moreover, the reaction also enables the C-N coupling of electron-withdrawing substrates and base-sensitive functionalities.
- Joshi, Raj Kumar,Sharma, Charu,Sharma, Kamal Nayan,Srivastava, Avinash Kumar
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supporting information
p. 3599 - 3606
(2020/06/10)
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- Copper-catalyzed direct amination of benzylic hydrocarbons and inactive aliphatic alkanes with arylamines
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A new synthetic method toward direct C-N bond formation through saturated C-H amination of benzylic hydrocarbons and inactive aliphatic alkanes with primary aromatic amines under an inexpensive catalyst/oxidant (Cu/DTBP) system has been developed. Both aminopyridines and anilines could react smoothly with primary and secondary benzylic C-H substrates or cyclohexane to form the corresponding aromatic secondary amines in moderate to good yields. This protocol has the advantages of wide functional group tolerance and use of readily available raw materials.
- Jin, Shengzhou,Lin, Sen,Xie, Bo,Yan, Zhaohua,Yao, Hua,Zhong, Xiaoyang
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supporting information
p. 3263 - 3268
(2020/05/14)
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- N-Benzylation of primary amines using magnetic Fe3O4 nanoparticles functionalized with hexamethylenetetramine as an efficient and recyclable heterogeneous catalyst
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Herein we report, a new, simple and mild procedure for N-benzylation and N,N-dibenzylation of anilines through the reaction of aniline derivatives and benzyl bromide at 60 °C in EtOH in the presence of catalytic amounts of magnetic Fe3O4 nanoparticles functionalized with hexamethylenetetramine (Fe3O4?SiO2?Propyl-HMTA). The title compounds were formed in high purity and their structures characterized by spectral analysis. The results also showed that the magnetic nanoparticle catalyst had significant advantages including, simplicity of preparation, heterogeneity, stability and recyclability. Moreover, the catalyst was characterized by various methods, such as FT-IR, SEM, VSM, TEM, TGA and XRD, after the reaction to compare with its structure before reaction.
- Ghorbani-Vaghei, Ramin,Mirzaei-Mosbat, Maryam,Noori, Samira
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- Band-Gap Narrowing of Highly Stable Heterogeneous ZrO2–ZnO Nanocomposites for the Reductive Amination of Carbonyl Compounds with Formic Acid and Triethylamine
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The band gap of a material can be affected by factors such as size, doping materials, and oxygen vacancies. The decrease in band gap and change in state of ZrO2 with the addition of ZnO indicates interfacial interactions between ZrO2 and ZnO in the nanocomposites (NCs), which is further confirmed by the observed shift of the peaks in the Raman spectra. Heterobimetallic ZrO2–ZnO NCs were synthesized through a sustainable green approach by using sucrose isolated from Angelica gigas Nakai root extract. The highly stable NCs displayed excellent catalytic activity for reductive amination of carbonyl compounds utilizing HCO2H/(CH3CH2)3N as a hydrogen source. The high catalytic performance of the NCs was closely correlated with the narrow band gap and synergistic effect of ZrO2 with ZnO in the NCs.
- Mishra, Kanchan,Kim, Sung Hong,Lee, Yong Rok
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p. 881 - 889
(2019/02/01)
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- Ultrasound-assisted synthesis of UiO-66-NHSO3H via post-synthetic modification as a heterogeneous Br?nsted acid catalyst
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Efficient SO3H-functionalized metal organic framework, UiO-66-NH-SO3H, has been successfully prepared through a post-synthetic modification strategy of UiO-66-NH2 with Chlorosulfonic acid reagent. The UiO-66-NH2 has been synthesized by an ultrasound-assisted (US) method and compared with the conventional-heating method. The UiO-66-NH-SO3H was characterized by elemental analysis, SEM, PXRD and FT-IR to serve as an efficient heterogeneous catalyst for the benzimidazole formation and reductive amination reaction. Furthermore, the UiO-66-NH-SO3H catalyst exhibits good stability, general applicability and excellent recycling performance.
- Homaee, Mahsa,Hamadi, Hosein,Nobakht, Valiollah,Javaherian, Mohammad,Salahshournia, Behrang
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p. 152 - 161
(2019/04/03)
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- Metal-Free Ring Opening Cyclization of Cyclopropane Carbaldehydes and N-Benzyl Anilines: An Eco-Friendly Access to Functionalized Benzo[b]azepine Derivatives
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Herein, we report a p-toluenesulfonic acid (PTSA) initiated mild and user-friendly ring opening/domino ring opening cyclization reaction (depends on substituent present in N-benzyl aniline) of cyclopropane carbaldehyde and N-benzyl aniline towards the formation of substituted 4-amino butanal/2,3-dihydro-1H-benzo[b]azepine. The product dihydro-1H-benzo[b]azepine was also converted into the corresponding tetrahydro-1H-benzo[b]azepine. (Figure presented.).
- Dey, Raghunath,Banerjee, Prabal
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p. 2849 - 2854
(2019/04/26)
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- Mechanistic Studies of Hydride Transfer to Imines from a Highly Active and Chemoselective Manganate Catalyst
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We introduce a highly active and chemoselective manganese catalyst for the hydrogenation of imines. The catalyst has a large scope, can reduce aldimines and ketimines, and tolerates a variety of functional groups, among them hydrogenation sensitive examples such as an olefin, a ketone, nitriles, nitro groups, and an aryl iodo substituent or a benzyl ether. We could investigate the transfer step between imines and the hydride complex in detail. We found that double deprotonation of the ligand is essential and excess base does not lead to a higher rate in the transfer step. We identified the actual hydrogenation catalyst as a K-Mn-bimetallic species and could obtain a structure of the K-Mn complex formed after hydride transfer by X-ray analysis. NMR experiments indicate that the hydride transfer is a well-defined reaction, which is first order in imine, first order in the bimetallic (K-Mn) hydride, and independent in rate from the concentration of the potassium base. We propose an outer-sphere mechanism in which protons do not seem to be involved in the rate-determining step, leading to a transiently negatively charged nitrogen atom in the substrate which reacts rapidly with HOtBu (2-methylpropan-2-ol) to produce the amine. This is based on several observations, such as no dependency of the reaction rate on the HOtBu concentration, no observable manganese amide complex, and a high reaction constant in a conducted Hammett study. Furthermore, hydrogen transfer of the catalytic cycle was experimentally probed and monitored by NMR with subsequent quantitative regeneration of the catalyst by H2.
- Freitag, Frederik,Irrgang, Torsten,Kempe, Rhett
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supporting information
p. 11677 - 11685
(2019/08/20)
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- Exploring the influence of designer surfactant hydrophobicity in key C–C/C–N bond forming reactions
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Designer micellar medium was explored for the transformation of diverse anilines to the corresponding densely substituted biologically relevant skatole derivatives in an aqueous medium via 5-exo-trig cyclization reaction. The scope of the reaction was extended to intermolecular Csp2-Csp2 and Csp2-N bond forming reactions in water. Systematic investigations revealed that altering hydrophobicity of surfactant influences the yield of both C–C and C–N bond forming reactions in water.
- Reddy, Singarajanahalli Mundarinti Krishna,Kothandapani, Jagatheeswaran,Sengan, Megarajan,Veerappan, Anbazhagan,Selva Ganesan, Subramaniapillai
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- Borrowing Hydrogen-Mediated N-Alkylation Reactions by a Well-Defined Homogeneous Nickel Catalyst
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We report herein a well-defined and bench-stable azo-phenolate ligand-coordinated nickel catalyst which can efficiently execute N-alkylation of a variety of anilines by alcohol. We demonstrate that the redox-active azo ligand can store hydrogen generated during alcohol oxidation and redelivers the same to an in-situ-generated imine bond to result in N-alkylation of amines. The reaction has wide scope, and a large array of alcohols can directly couple to a variety of anilines. Mechanistic studies including deuterium labeling to the substrate establishes the borrowing hydrogen method from alcohols and pinpoints the crucial role of the redox-active azo moiety present on the ligand backbone. Isolation of the ketyl intermediate in its trapped form with a radical quencher and higher kH/kD for the alcohol oxidation step suggest altogether a hydrogen-atom transfer (HAT) to the reduced azo backbone to pave alcohol oxidation as opposed to the conventional metal-ligand bifunctional mechanism. This example clearly demonstrates that an inexpensive base metal catalyst can accomplish an important coupling reaction with the help of a redox-active ligand backbone.
- Bains, Amreen K.,Kundu, Abhishek,Yadav, Sudha,Adhikari, Debashis
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p. 9051 - 9059
(2019/10/02)
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- Plasma-Made (Ni0.5Cu0.5)Fe2O4 Nanoparticles for Alcohol Amination under Microwave Heating
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Amine N-alkylation is a process involved in the production of a wide range of chemicals. Here we describe the synthesis of well-defined (Ni0.5Cu0.5)Fe2O4 magnetic nanoparticles by plasma induction, and their successful application to amine N-alkylation using alcohols as coupling agents through a borrowing hydrogen pathway. Plasma induction allows precise morphology and size control over nanoparticle synthesis, while allowing the one-pot production of decagram quantities of material. Up to date, such nanoparticles have never been applied for organic reactions. By coupling high-end characterization techniques with catalytic optimization, we showed that small Cu(0) satellite nanoparticles played an essential role in alcohol oxidation, whereas both Ni and Cu were required for the last step of the reaction. Using elemental mapping, we demonstrated that catalyst deactivation occurred through a leaching/re-deposition mechanism of Cu and Ni. The reactions were conducted under microwave conditions, which exerted a positive effect on catalytic activity. Finally, the catalyst was active at low metal loadings (2 mol%) even on the gram-scale, and affording unprecedented TON for this reaction catalyzed by Ni/Cu bimetallic systems (19).
- Li, Alain You,Dumaresq, Nicolas,Segalla, Andréanne,Braidy, Nadi,Moores, Audrey
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p. 3959 - 3972
(2019/08/12)
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- Oxalic amide ligands, and uses thereof in copper-catalyzed coupling reaction of aryl halides
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The present invention provides oxalic amide ligands and uses thereof in copper-catalyzed coupling reaction of aryl halides. Specifically, the present invention provides a use of a compound represented by formula I, wherein definitions of each group are described in the specification. The compound represented by formula I can be used as a ligand in copper-catalyzed coupling reaction of aryl halides for the formation of C—N, C—O and C—S bonds.
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Page/Page column 77-78
(2020/01/09)
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- Regioselective Nitration of N-Alkyl Anilines using tert-Butyl Nitrite under Mild Condition
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Regioselective ring nitration of N-alkyl anilines is reported using tert-butyl nitrite. The reactions proceed efficiently with a wide range of substrates providing synthetically useful N-nitroso N-alkyl nitroanilines in excellent yields which can be easily converted into N-alkyl phenylenediamines and N-alkyl nitroanilines using Zn-AcOH and HCl/MeOH, respectively.
- Chaudhary, Priyanka,Gupta, Surabhi,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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p. 104 - 119
(2019/01/08)
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- Amination of Aromatic Halides and Exploration of the Reactivity Sequence of Aromatic Halides
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A base-promoted amination of aromatic halides has been developed using a limited amount of dimethylformamide (DMF) or amine as an amino source. Various aryl halides, including F, Cl, Br, and I, have been successfully aminated in good to excellent yields. Although the amination of aromatic halides with amines or DMF is usually considered as an aromatic nucleophilic substitution (SNAr) process, and the reactivity of an aromatic halide is F > Cl > Br > I, the reactivity of aromatic halides in this system was found to be I > Br a‰ F > Cl. This protocol also showed a good regioselectivity for multihalogenated aromatics. This protocol is valuable for industrial application due to the simplicity of operation, the unrestricted availability of amino sources and aromatic halides, transition metal-free conditions, no requirement for solvent, and scalability.
- Yang, Chu,Zhang, Feng,Deng, Guo-Jun,Gong, Hang
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p. 181 - 190
(2019/01/10)
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- An Efficient Metal-Free Mono N-Alkylation of Anilines via Reductive Amination Using Hydrosilanes
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2-Aminoquinazolin-4-one based efficient organocatalytic eco-friendly reductive amination approach was developed for the mono N-alkylation of anilines using hydrosilane as a reducing agent. This practically easy and sustainable approach works under neat reaction conditions and utilizes non-toxic environmentally benign acetic acid as a dehydrating agent. The developed protocol have several advantages, such as broad substrate scope, wide functional group tolerance, short reaction time, and absence of metal catalyst in the reaction.
- Thakur, Maheshwar S.,Nayal, Onkar S.,Sharma, Arti,Rana, Rohit,Kumar, Neeraj,Maurya, Sushil K.
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supporting information
p. 6729 - 6732
(2018/11/23)
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- Main-Group-Catalyzed Reductive Alkylation of Multiply Substituted Amines with Aldehydes Using H2
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Given the growing demand for green and sustainable chemical processes, the catalytic reductive alkylation of amines with main-group catalysts of low toxicity and molecular hydrogen as the reductant would be an ideal method to functionalize amines. However, such a process remains challenging. Herein, a novel reductive alkylation system using H2 is presented, which proceeds via a tandem reaction that involves the B(2,6-Cl2C6H3)(p-HC6F4)2-catalyzed formation of an imine and the subsequent hydrogenation of this imine catalyzed by a frustrated Lewis pair (FLP). This reductive alkylation reaction generates H2O as the sole byproduct and directly functionalizes amines that bear a remarkably wide range of substituents including carboxyl, hydroxyl, additional amino, primary amide, and primary sulfonamide groups. The synthesis of isoindolinones and aminophthalic anhydrides has also been achieved by a one-pot process that consists of a combination of the present reductive alkylation with an intramolecular amidation and intramolecular dehydration reactions, respectively. The reaction showed a zeroth-order and a first-order dependence on the concentration of an imine intermediate and B(2,6-Cl2C6H3)(p-HC6F4)2, respectively. In addition, the reaction progress was significantly affected by the concentration of H2. These results suggest a possible mechanism in which the heterolysis of H2 is facilitated by the FLP comprising THF and B(2,6-Cl2C6H3)(p-HC6F4)2.
- Hoshimoto, Yoichi,Kinoshita, Takuya,Hazra, Sunit,Ohashi, Masato,Ogoshi, Sensuke
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supporting information
p. 7292 - 7300
(2018/06/01)
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- Unmodified Fe3O4 nanostructure promoted with external magnetic field: safe, magnetically recoverable, and efficient nanocatalyst for N- and C-alkylation reactions in green conditions
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Transition metal compounds have emerged as suitable catalysts for organic reactions. Magnetic compounds as soft Lewis acids can be used as catalysts for organic reactions. In this report, the Fe3O4 nanostructures were obtained from Fe2+ and Fe3+-salts, under an external magnetic field (EMF) without any protective agent. The X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy tools were used to characterize these magnetic compounds. The two-dimensional (2-D, it showed nanometric size in the two dimensions, nanorod structure) Fe3O4 compound showed high catalytic activity and stability in N- and C-alkylation reactions. A diverse range of N- and C-alkylation products were obtained in moderate to high yield under green and mild conditions in air. Also the N- and C-alkylation products can be obtained with different selectivity and yield by exposure reactions with EMF. Results of alkylation reactions showed that the presence of Fe(II) and Fe(III) species on the surface of magnetic catalysts (phase structure of magnetic compounds) are essential as very cheap active sites. Also, morphology of magnetic catalysts had influence on their catalytic performances. After the reaction, the catalyst/product(s) separation could be easily achieved with an external magnet and more than 95% of catalyst could be recovered. The catalyst was reused at least four times without any loss of its high catalytic activity for N- and C-alkylation reactions.
- Rafiee, Ezzat,Joshaghani, Mohammad,Abadi, Parvaneh Ghaderi-Shekhi
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p. 2503 - 2522
(2018/01/04)
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- An Effective Heterogeneous Copper Catalyst System for C-N Coupling and Its Application in the Preparation of 2-Methyl-4-methoxydiphenylamine (MMDPA)
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A ligand-recyclable, environmentally benign heterogeneous catalyst system composed of CuI and polystyrene-supported N (-(4-(aminomethyl)naphthalen-1-yl)- N (-phenyl-1 H -pyrrole-2-carbohydrazide (PSAP) has been established for Ullmann type C-N coupling based on the homogeneous catalyst system N ′, N ′-diphenyl-1 H -pyrrole-2-carbohydrazide/CuI. This heterogeneous catalyst system maintained the catalytic effectiveness of the homogeneous catalyst. A variety of functionalized aryl bromides can be efficiently aminated with aryl amines and aliphatic amines with high selectivity for amines over alcohols. Moreover, a practical application of this catalyst system to promote the reaction of commercially available 4-methoxy-2-methylaniline and bromobenzene in 10 mmol scale, provided 2-methyl-4-methoxydiphenylamine (MMDPA) with 93% yield with the merit of the approach being simple operation for work-up and purification.
- Yi, Zhou,Huang, Manna,Wan, Yiqian,Zhu, Xinhai
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p. 3911 - 3920
(2018/09/29)
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- Metal- and Base-Free Room-Temperature Amination of Organoboronic Acids with N-Alkyl Hydroxylamines
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We have found that readily available N-alkyl hydroxylamines are effective reagents for the amination of organoboronic acids in the presence of trichloroacetonitrile. This amination reaction proceeds rapidly at room temperature and in the absence of added metal or base, it tolerates a remarkable range of functional groups, and it can be used in the late-stage assembly of two complex units.
- Sun, Hong-Bao,Gong, Liang,Tian, Yu-Biao,Wu, Jin-Gui,Zhang, Xia,Liu, Jie,Fu, Zhengyan,Niu, Dawen
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supporting information
p. 9456 - 9460
(2018/07/29)
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- PdAu@MIL-100(Fe) cooperatively catalyze tandem reactions between amines and alcohols for efficient N-alkyl amines syntheses under visible light
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PdAu@MIL-100(Fe), with PdAu alloy nanoparticles of ca. 1.7 nm encapsulated inside MIL-100(Fe) cavities, were prepared via a double-solvent impregnation followed by photoreduction. As compared with bare Pd@MIL-100(Fe), bimetallic PdAu@MIL-100(Fe) showed superior activities for the tandem reactions between amines and alcohols to produce N-alkyl amines under visible-light irradiation, ascribed to the promoting effect of metallic Au in the photocatalytic alcohol-to-aldehyde dehydrogenation. A Pd/Au ratio dependent N-alkylation activity was observed over PdAu@MIL-100(Fe), implying the possibility of synchronizing the reaction rates of two consecutive steps in the N-alkylation reaction, i.e., photocatalytic alcohol-to-aldehyde dehydrogenation and imines hydrogenation, to optimize the whole reaction. This study provides a highly efficient and stable catalytic system for the realization of alkylation of amines via a successful coupling of MOF-based photocatalysis and metal nanoparticle-based hydrogenation. This work also demonstrates that the reaction rates of different catalytic steps in a cascade/tandem reaction can be synchronized for an efficient overall reaction via a rational design of the multifunctional catalysts.
- Wang, Dengke,Pan, Yating,Xu, Lizhi,Li, Zhaohui
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p. 248 - 254
(2018/04/02)
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- One-pot Reductive Amination of Carbonyl Compounds with NaBH4-B(OSO3H)3/SiO2 in Acetonitrile and in Solvent-free Condition
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An efficient one-pot procedure for the direct reductive amination of aldehyde and ketones was achieved in the presence of sodium borohydride by using B(OSO3H)3/SiO2(SBSA) as the reusable solid catalyst in acetonitrile and solvent-free conditions. Both aromatic and aliphatic aldehyde reacted well to give the corresponding amines in excellent yields. All the products are known and well-characterized. The catalyst is recoverable and could be easily recycled by filtration and reused several times without any significant loss of its activity. SBSA acts as a dual Br?nsted/Lewis acid that is an air-stable and cost-effective solid acid. [Figure not available: see fulltext.]
- Hamadi, Hosein,Javadi, Samira
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- Water-Soluble Iridium N-Heterocyclic Carbene Complexes for the Alkylation of Amines with Alcohols
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A new series of water-soluble Ir complexes with N-heterocyclic carbene ligands that bear ester and amide groups has been obtained and fully characterized. The new complexes are highly reactive and selective for the alkylation of amines with alcohols with a 1:1 ratio of reactants in water and in the absence of base or other additives. The catalytic system has a broad substrate scope, which allows the synthesis of a variety of primary and secondary amines in excellent yields. A tolerance to a large range of functional groups was obtained.
- Fernandes, Ana,Royo, Beatriz
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p. 3912 - 3917
(2017/09/28)
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- An Efficient and Selective Nickel-Catalyzed Direct N-Alkylation of Anilines with Alcohols
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Herein, we developed an efficient and selective nickel-catalyzed monoalkylation of various primary alcohols with aryl and heteroaryl amines together with diols and amino alcohol derivatives. Notably, the catalytic protocol consisting of an earth-abundant and non-precious NiBr2/L1 system enables the transformations in the presence of hydroxyl, alkene, nitrile, and nitro functionalities. As a highlight, we have demonstrated the alkylation of diamine, intramolecular cyclization to N-heterocycles, and functionalization of complex vitamin E, an (±)-α-tocopherol derivative. Preliminary mechanistic studies revealed the participation of a benzylic C-H bond in the rate-determining step.
- Vellakkaran, Mari,Singh, Khushboo,Banerjee, Debasis
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p. 8152 - 8158
(2017/12/08)
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- Copper immobilized on magnetite nanoparticles coated with ascorbic acid: An efficient and reusable catalyst for C─N and C─O cross-coupling reactions
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In a continuation of using magnetic nanoparticle (MNP)-supported catalysts, ascorbic acid (readily available, very safe and with strong affinity to MNPs) was used instead of the commonly used silica layer coating. This hybrid was used for immobilizing copper nanoparticles to produce Cu/ascorbic acid@MNPs catalyst. The catalyst was characterized and used in carbon–oxygen and carbon–nitrogen (various substrates) cross-coupling reactions in aqueous media and at room temperature with excellent product yields. Furthermore, the catalyst could be quickly and completely recovered using an external magnetic field and reused for six reaction cycles without significant change in catalytic activity.
- Hajipour, Abdol R.,Check, Maryam,Khorsandi, Zahra
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- Room-Temperature CuI-Catalyzed Amination of Aryl Iodides and Aryl Bromides
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A general and effective CuI/N′,N′-diaryl-1H-pyrrole-2-carbohydrazide catalyst system was developed for the amination of aryl iodides and bromides at room temperature with good chemoselectivity between -OH and -NH2 groups. Only 5 mol % of CuI and ligands was needed in this protocol to effect the amination of various aryl bromides and aryl iodides with a wide range of aliphatic and aryl amines (1.3 equiv).
- Ding, Xiaomei,Huang, Manna,Yi, Zhou,Du, Dongchen,Zhu, Xinhai,Wan, Yiqian
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p. 5416 - 5423
(2017/05/25)
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- A process for the preparation method of the compound aromatic amines (by machine translation)
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The invention discloses a method for preparing aromatic amine compounds, comprising the following steps: under protection of inert gas, with the ratio of the phenolic compound amine according to mole 1:2 - 40 are mixed and dissolved in the solvent, 50 - 140 °C reaction 6 - 15 hours, corresponding to preparing polymerizable aromatic amine compound, and then after treatment to obtain a pure aromatic amine compound. Raw materials of this invention generally are easy, simple operation, substrate and wide range of application, in the absence of catalyst under catalytic conditions of the phenolic compound can be obtained by nucleophilic addition reaction of the corresponding aromatic amine compound, and is suitable for industrial production. The present invention allows the presence of water in the reaction system, can be ammonia or hydrazine hydrate as the substrate, in order to ammonium chloride as a catalyst and a cosolvent, the success of the preparation to obtain a level from phenol hydroxy aromatic primary amino compound. The invention to phenol hydroxy has better selectivity, even if the presence of halogen atoms in the substrate does not affect the occurrence of the reaction. (by machine translation)
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Paragraph 0043; 0044; 0045; 0046
(2017/07/18)
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- Magnetic nanoparticle-supported phosphine gold(i) complex: A highly efficient and recyclable catalyst for the direct reductive amination of aldehydes and ketones
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The direct reductive amination of aldehydes and ketones has been achieved in dichloromethane at room temperature by using a magnetic nanoparticle-supported phosphine gold(i) complex [Fe3O4@SiO2-P-AuCl] as the catalyst and ethyl Hantzsch ester as the hydrogen source, yielding a variety of secondary amines in excellent yields under neutral conditions. The new heterogeneous gold catalyst can be prepared by a simple procedure from commercially readily available reagents and can easily be separated from the reaction mixture by applying an external magnet and recycled at least 10 times without any loss of activity.
- Yang, Weisen,Wei, Li,Yi, Feiyan,Cai, Mingzhong
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p. 4554 - 4564
(2016/07/06)
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- B(C6F5)3-Catalyzed Reductive Amination using Hydrosilanes
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In contrast to the established dogma that B(C6F5)3 is irreversibly poisoned by excess H2O/amine (or imine) bases, B(C6F5)3 is actually a water-tolerant catalyst for the reductive amination of primary and secondary arylamines with aldehydes and ketones in "wet solvents" at raised temperatures and using only 1.2 equiv of Me2PhSiH as reductant. Arylamines/N-arylimines do not result in the irreversible deprotonation of H2O-B(C6F5)3, allowing sufficient B(C6F5)3 to be evolved at raised temperatures to effect catalytic reductions. Stronger Br?nsted basic amines such as tBuNH2 (and derived imines) result in irreversible formation of [HO-B(C6F5)3]- from H2O-B(C6F5)3, precluding the formation of B(C6F5)3 at raised temperatures and thus preventing any imine reduction. A substrate scope exploration using 1 mol % nonpurified B(C6F5)3 and "wet solvents" demonstrates that this is an operationally simple and effective methodology for the production of secondary and tertiary arylamines in high yield, with imine reduction proceeding in preference to other possible reactions catalyzed by B(C6F5)3, including the dehydrosilylation of H2O and the reduction of carbonyl moieties (e.g., esters).
- Fasano, Valerio,Radcliffe, James E.,Ingleson, Michael J.
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p. 1793 - 1798
(2016/03/15)
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- Facile aromatic nucleophilic substitution (SNAr) reactions in ionic liquids: An electrophile-nucleophile dual activation by [Omim]Br for the reaction
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A facile aromatic nucleophilic substitution (SNAr) reaction in recyclable [Omim]Br under relatively mild conditions has been described. An electrophile-nucleophile dual activation by [Omim]Br is also discovered based on control experiments, 1H NMR and IR spectroscopies. This chemistry provides an efficient and metal-free approach for the generation of Caryl-X (XS, N, O) bonds, many of which are significant synthetic intermediates or drugs, making this methodology attractive to both synthetic and medicinal chemistry.
- Zhang, Xiao,Lu, Guo-Ping,Cai, Chun
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p. 5580 - 5585
(2016/10/21)
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- A quick Chan-Lam C-N and C-S cross coupling at room temperature in the presence of square pyramidal [Cu(DMAP)4I]I as a catalyst
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A rapid and efficient protocol for C-N and C-S cross coupling has been developed using a new square pyramidal copper complex, [Cu(DMAP)4I]I. The complex was successfully synthesized via a disproportionation reaction of CuI and DMAP in DMSO. The catalytic activity of the complex was found to be excellent for Chan-Lam coupling reaction between aryl boronic acid and amine, amide, azide or thiol. The reaction could be carried out in the presence of only 2 mol% of the copper catalyst in methanol at room temperature within a short time.
- Roy, Subhasish,Sarma, Manas Jyoti,Kashyap, Bishwapran,Phukan, Prodeep
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supporting information
p. 1170 - 1173
(2016/01/15)
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- A 1,10-phenanthrene rowling-N-Monoxide derivatives ligand and its application
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The invention relates to a 1,10-Phenanthroline monohydrate-dual N-monoxide derivative ligand. The derivative ligand has a structural formula as follows: FORMULA, wherein R1 and R8 are selected from hydrogen, halogen, hydroxyl, C1-C7 alkoxyl, straight-chain saturated or unsaturated C1-C6 alkyl, or branched-chain saturated or unsaturated C1-C6 alkyl; R2 to R7 are selected from hydrogen, halogen, hydroxyl, C1-C8 alkoxyl, straight-chain saturated or unsaturated C1-C6 alkyl, or branched-chain saturated or unsaturated C1-C6 alkyl, C3-C7 ring hydroxyl, benzyl, aryl or 5-7 membered heterocyclic ring. Hetero atoms (such as O or N) are contained in the ligand disclosed by the invention, and a transitional six-membered ring is formed through coordination with copper ions, so that aryl iodide, aryl bromide or aryl chloride is promoted to carry out a C-N coupling reaction with aliphatic amine or secondary aliphatic cyclammonium or aliphatic acid or nitrogen-containing heterocyclic compounds at room temperature.
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Paragraph 0250-0261
(2016/11/21)
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- Catalytic reduction of amides to amines by electrophilic phosphonium cations via FLP hydrosilylation
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A catalytic methodology for the conversion of amides to amines is reported. Of the 25 examples described, 14 examples involve the reduction of N-trifluoroacetamides to the corresponding trifluoroethylamines. These reductions are achieved by catalytic hydrosilylation of the amide mediated by an electrophilic phosphonium cation (EPC) catalyst.
- Augurusa, Alessandra,Mehta, Meera,Perez, Manuel,Zhu, Jiangtao,Stephan, Douglas W.
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supporting information
p. 12195 - 12198
(2016/10/21)
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- Transfer hydrogenative reductive amination of aldehydes in aqueous sodium formate solution
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A practical direct reductive amination reaction of aldehydes in aqueous sodium formate solution which produces amines in good yields under mild conditions is described. The amount and strength of the acid additives were critical factors to affect the reaction selectivities. This reductive amination method has great application potential for the synthesis of amine products given the mild conditions, short reaction time, the use of water as a solvent, and the use of benign hydrogen sources.
- Zhu, Mengping
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p. 509 - 511
(2016/01/12)
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- Highly Stable Mesoporous Zirconium Porphyrinic Frameworks with Distinct Flexibility
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The construction of highly stable metal-porphyrinic frameworks (MPFs) is appealing as these materials offer great opportunities for applications in artificial light-harvesting systems, gas storage, heterogeneous catalysis, etc. Herein, we report the synthesis of a novel mesoporous metal-porphyrinic framework (denoted as NUPF-1) and its catalytic properties. NUPF-1 is constructed from a new porphyrin linker and a Zr6O8 structural building unit, possessing an unprecedented doubly interpenetrating scu net. The structure exhibits not only remarkable chemical and thermal stabilities, but also a distinct structural flexibility, which is seldom seen in metal-organic framework (MOF) materials. By the merit of high chemical stability, NUPF-1 could be easily post-metallized with [Ru3(CO)12], and the resulting {NUPF-1-RuCO} is catalytically active as a heterogeneous catalyst for intermolecular C(sp3)-H amination. Excellent yields and good recyclability for amination of small substrates with various organic azides have been achieved.
- Xu, Lei,Luo, Yan-Ping,Sun, Lin,Xu, Yan,Cai, Zhong-Sheng,Fang, Min,Yuan, Rong-Xin,Du, Hong-Bin
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supporting information
p. 6268 - 6276
(2016/05/02)
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- NaBH4/PhCO2H: An efficient system for reductive amination of aldehydes
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NaBH4/PhCO2H system has been used for thereductive aminationofa varietyof aldehydes withanilines. The reductive amination reactions have been performed within 60-120 min in THFunder reflux conditionsin high to excellent yields of products (85-95%).
- Mohammadi, Nima,Setamdideh, Davood
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p. 2435 - 2437
(2016/02/27)
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- Chemoselective reductive amination of carbonyl compounds for the synthesis of tertiary amines using SnCl2·2H2O/PMHS/MeOH
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Stannous chloride catalyzed chemoselective reductive amination of a variety of carbonyl compounds with aromatic amines has been developed for the synthesis of a diverse range of tertiary amines using inexpensive polymethylhydrosiloxane as reducing agent in methanol. The present method is also applicable for the synthesis of secondary amines including heterocyclic ones.
- Nayal, Onkar S.,Bhatt, Vinod,Sharma, Sushila,Kumar, Neeraj
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p. 5912 - 5918
(2015/06/16)
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- Metal-free reductive amination of aldehydes for the synthesis of secondary and tertiary amines
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Reductive amination of aldehydes to produce secondary amines at room-temperature by in situ generated benzimidazoline is discussed. The bonus of the reaction is the formation of pharmaceutically important benzimidazole as a by-product in good yield, which can be recovered from the reaction mixture by simple filtration. The product, secondary amine, is transformed to tertiary amine in the same pot.
- Ambica,Khajuria, Rajni,Saini, Yeshwinder,Kapoor, Kamal K
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p. 1252 - 1259
(2015/11/25)
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