- Highly productive CO2 hydrogenation to methanol-a tandem catalytic approach: Via amide intermediates
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A new system for CO2 reduction to methanol has been demonstrated using homogeneous ruthenium catalysts with a range of amine auxiliaries. Modification of this amine has a profound effect on the yield and selectivity of the reaction. A TON of 8900 and TOF of 4500 h-1 is achieved using a [RuCl2(Ph2PCH2CH2NHMe)2] catalyst with a diisopropylamine auxiliary.
- Everett,Wass
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Read Online
- Additive-free selective methylation of secondary amines with formic acid over a Pd/In2O3 catalyst
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Formic acid is used as the sole carbon and hydrogen source in the methylation of aromatic and aliphatic amines to methylamines. The reaction proceeds via a formylation/transfer hydrogenation pathway over a solid Pd/In2O3 catalyst without the need for any additive.
- Benaissa, Idir,Cantat, Thibault,Genre, Caroline,Godou, Timothé,Pinault, Mathieu
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- Highly Efficient and Selective N-Formylation of Amines with CO2 and H2 Catalyzed by Porous Organometallic Polymers
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The valorization of carbon dioxide (CO2) to fine chemicals is one of the most promising approaches for CO2 capture and utilization. Herein we demonstrated a series of porous organometallic polymers could be employed as highly efficient and recyclable catalysts for this purpose. Synergetic effects of specific surface area, iridium content, and CO2 adsorption capability are crucial to achieve excellent selectivity and yields towards N-formylation of diverse amines with CO2 and H2 under mild reaction conditions even at 20 ppm catalyst loading. Density functional theory calculations revealed not only a redox-neutral catalytic pathway but also a new plausible mechanism with the incorporation of the key intermediate formic acid via a proton-relay process. Remarkably, a record turnover number (TON=1.58×106) was achieved in the synthesis of N,N-dimethylformamide (DMF), and the solid catalysts can be reused up to 12 runs, highlighting their practical potential in industry.
- Shen, Yajing,Zheng, Qingshu,Chen, Zhe-Ning,Wen, Daheng,Clark, James H.,Xu, Xin,Tu, Tao
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supporting information
p. 4125 - 4132
(2021/01/12)
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- N-formylation of amines using phenylsilane and CO2 over ZnO catalyst under mild condition
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Several research studies have been conducted on N-formylation of amines using phenylsilane and CO2. However, most of these studies involved tedious processes of catalyst preparation or complex procedures. In the present study, we describe the use of a simple and commercially available ZnO catalyst for selective N-formylation of amines under mild condition. High-yielding N-formylation products with good recyclability and wide substrate scope were obtained, which can promote fine chemical synthesis and CO2 capture.
- Cheng, Yujie,Gan, Tao,He, Qian,He, Xiaohui,Ji, Hongbing,Sun, Qingdi,Wang, Pengbo,Zhang, Hao
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- A N-Phosphinoamidinato NHC-Diborene Catalyst for Hydroboration
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The use of the N-phosphinoamidinato NHC-diborene catalyst 2 for hydroboration is described. The N-phosphinoamidine tBu2PN(H)C(Ph)= N(2,6-iPr2C6H3) was reacted with nBuLi in Et2O to afford the lithium derivative, which was then treated with B2Br4(SMe2)2 in toluene to form the N-phosphinoamidinate-bridged diborane 1. It was reacted with the N-heterocyclic carbene IMe (:C{N(CH3)C(CH3)}2) and excess potassium graphite at room temperature in toluene to give the N-phosphinoamidinato NHC-diborene compound 2. It can stoichiometrically activate ammonia-borane and carbon dioxide. It also showed catalytic capability. A 2 mol % portion of 2 catalyzed the hydroboration of carbon dioxide (CO2) with pinacolborane (HBpin) in deuterated benzene (C6D6) at 110 °C (conversion >99%), which afforded the methoxyborane [pinBOMe] (yield 97.8%, TOF 33.3 h-1) and the bis(boryl) oxide [(pinB)2O]. In addition, 5 mol % of 2 catalyzed the N-formylation of secondary and primary amines by carbon dioxide and pinacolborane to yield the N-formamides (average yield 91.6%, TOF 25.9 h-1). Moreover, 2 showed chemoselectivity toward catalytic hydroboration of carbonyl compounds. In mechanistic studies, the B= B double bond in compound 2 activated the substrates, the intermediates of which then underwent hydroboration with pinacolborane to yield the products and regenerate catalyst 2.
- Fan, Jun,Mah, Jian-Qiang,Yang, Ming-Chung,Su, Ming-Der,So, Cheuk-Wai
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supporting information
p. 4993 - 5002
(2021/02/01)
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- Copper-Catalyzed Formylation of Amines by using Methanol as the C1 Source
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Cu/TEMPO catalyst systems are known for the selective transformation of alcohols to aldehydes, as well as for the simultaneous coupling of alcohols and amines to imines under oxidative conditions. In this study, such a Cu/TEMPO catalyst system is found to catalyze the N-formylation of a variety of amines by initial oxidative activation of methanol as the carbonyl source via formaldehyde and formation of N,O-hemiacetals and oxidation of the latter under very mild conditions. A vast range of amines, including aromatic and aliphatic, primary and secondary, and linear and cyclic amines are formylated under these conditions with good to excellent yields. Moreover, paraformaldehyde can be used instead of methanol for the N-formylation.
- Pichardo, Manuel Carmona,Tavakoli, Ghazal,Armstrong, Jessica E.,Wilczek, Tobias,Thomas, Bradley E.,Prechtl, Martin H. G.
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p. 882 - 887
(2020/02/11)
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- Tetracoordinate borates as catalysts for reductive formylation of amines with carbon dioxide
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We report sodium trihydroxyaryl borates as the first robust tetracoordinate organoboron catalysts for reductive functionalization of CO2. These catalysts, easily synthesized from condensing boronic acids with metal hydroxides, activate main group element-hydrogen (E-H) bonds efficiently. In contrast to BX3 type boranes, boronic acids and metal-BAr4 salts, under transition metal-free conditions, sodium trihydroxyaryl borates exhibit high reactivity of reductive N-formylation toward a variety of amines (106 examples), including those with functional groups such as ester, olefin, hydroxyl, cyano, nitro, halogen, MeS-, ether groups, etc. The over-performance to catalyze formylation of challenging pyridyl amines affords a promising alternative method to the use of traditional formylation reagents. Mechanistic investigation supports electrostatic interactions as the key for Si/B-H activation, enabling alkali metal borates as versatile catalysts for hydroborylation, hydrosilylation, and reductive formylation/methylation of CO2.
- Du, Chen-Xia,Huang, Zijun,Jiang, Xiaolin,Li, Yuehui,Makha, Mohamed,Wang, Fang,Zhao, Dongmei
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supporting information
p. 5317 - 5324
(2020/09/17)
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- A NHC-silyliumylidene cation for catalytic N?formylation of amines using carbon dioxide
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This study describes the use of a silicon(II) complex, namely, the NHC-silyliumylidene cation complex [(IMe)2SiH]I (1, IMe =:C{N(Me)C(Me)}2), to catalyze the chemoselective N-formylation of primary and secondary amines using CO2 and PhSiH3 under mild conditions to afford the corresponding formamides as a sole product (average reaction time: 4.5 h; primary amines, average yield: 95%, average TOF: 8 h?1; secondary amines, average yield: 98%, average TOF: 17 h?1). The activity of 1 and product yields outperform the currently available non-transition-metal catalysts used for this catalysis. Mechanistic studies show that the silicon(II) center in complex 1 catalyzes the C?N bond formation via a different pathway in comparison with non-transition-metal catalysts. It sequentially activates CO2, PhSiH3, and amines, which proceeds via a dihydrogen elimination mechanism, to form formamides, siloxanes, and dihydrogen gas.
- Leong, Bi-Xiang,Teo, Yeow-Chuan,Condamines, Cloe,Yang, Ming-Chung,Su, Ming-Der,So, Cheuk-Wai
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p. 14824 - 14833
(2020/12/21)
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- Zinc Powder Catalysed Formylation and Urealation of Amines Using CO2 as a C1 Building Block?
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Transformation of CO2 into valuable organic compounds catalysed by cheap and biocompatible metal catalysts is one of important topics of current organic synthesis and catalysis. Herein, we report the zinc powder catalysed formylation and urealation of amines with CO2 and (EtO)3SiH under solvent free condition. Using 2 molpercent zinc powder as the catalyst, a series of secondary amines, both the aromatic ones and the aliphatic ones, can be formylated into formamides. When primary aromatic amines were used as the substrates, the reactions produce urea derivatives. The electronic and steric effects from the substrates on the formylation and urealation reactions were observed and discussed. The recovery and reusability of zinc powder were investigated, showing the zinc powder can be reused in the formylation reaction without loss of catalytic activity. The analysis on the reactants/products mixture after filtering out the zinc powder showed the zinc concentration in the mixture is low to 1 ppm. The pathways for the formylation and urealation of amines with this catalytic system were also investigated, and related to the different substrates.
- Du, Chongyang,Chen, Yaofeng
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p. 1057 - 1064
(2020/06/30)
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- Engineering Porphyrin Metal-Organic Framework Composites as Multifunctional Platforms for CO2Adsorption and Activation
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As an effective solution toward the establishment of a sustainable society, the reductive transformation of CO2 into value-added products is certainly important and imperative. Herein, we report a porphyrin metal-organic framework composite Au@Ir-PCN-222, which is obtained through the in situ formation of Au nanoparticles in the coordination interspaces of Ir-PCN-222. Catalytic results show that Au@Ir-PCN-222 is highly efficient for CO2 reduction and aminolysis, giving rise to formamides in high yields and selectivities under room temperature and atmospheric pressure. Mechanistic studies disclose that the high efficiency of Au@Ir-PCN-222 is due to the synergistic catalysis of Au NPs and Ir-PCN-222, in which Au NPs can adsorb CO2 molecules on their surfaces and then increase the CO2 concentration in the cavities of the framework, and at the same time, Au NPs transfer electrons to Ir-porphyrin units and therefore increase the interactions with CO2 molecules.
- Liu, Jiewei,Fan, Yan-Zhong,Zhang, Kun,Zhang, Li,Su, Cheng-Yong
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p. 14548 - 14556
(2020/10/13)
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- Practical Catalytic Cleavage of C(sp3)?C(sp3) Bonds in Amines
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The selective cleavage of thermodynamically stable C(sp3)?C(sp3) single bonds is rare compared to their ubiquitous formation. Herein, we describe a general methodology for such transformations using homogeneous copper-based catalysts in the presence of air. The utility of this novel methodology is demonstrated for Cα?Cβ bond scission in >70 amines with excellent functional group tolerance. This transformation establishes tertiary amines as a general synthon for amides and provides valuable possibilities for their scalable functionalization in, for example, natural products and bioactive molecules.
- Li, Wu,Liu, Weiping,Leonard, David K.,Rabeah, Jabor,Junge, Kathrin,Brückner, Angelika,Beller, Matthias
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supporting information
p. 10693 - 10697
(2019/07/09)
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- N-Formylation of Amines with CO2 and H2 by Using NHC–Iridium Coordination Assemblies as Solid Molecular Catalysts
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One of the NHC–iridium coordination assemblies containing 1,5-cyclooctadiene (COD) and iodide ion has been demonstrated as robust, efficient, recyclable solid molecular catalyst for N-formylation of diverse primary and secondary amines with CO2 and H2 under mild reaction conditions. Remarkably, in the case of N,N-dimethylformamide production, even at 0.1 mol % catalyst loading under solvent-free conditions, the solid catalyst can be readily recovered by simply filtration and reused more than 10 runs without noticeable loss of activity.
- Zhang, Yang,Wang, Jiaquan,Zhu, Haibo,Tu, Tao
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supporting information
p. 3018 - 3021
(2018/09/06)
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- Polymer Meets Frustrated Lewis Pair: Second-Generation CO2-Responsive Nanosystem for Sustainable CO2 Conversion
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Frustrated Lewis pairs (FLP), a couple comprising a sterically encumbered Lewis acid and Lewis base, can offer latent reactivity for activating inert gas molecules. However, their use as a platform for fabricating gas-responsive materials has not yet developed. Merging the FLP concept with polymers, we report a new generation CO2-responsive system, differing from the first-generation ones based on an acid–base equilibrium mechanism. Two complementary Lewis acidic and basic block copolymers, installing bulky borane- and phosphine-containing blocks, were built as the macromolecular FLP. They can bind CO2 to drive micellar formation, in which CO2 as a cross-linker bridges the block chains. This dative bonding endows the assembly with ultrafast response (2 can function as nanocatalysts for recyclable C1 catalysis, opening a new direction of sustainable CO2 conversion.
- Chen, Liang,Liu, Renjie,Yan, Qiang
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supporting information
p. 9336 - 9340
(2018/07/25)
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- Preparation method of formamide compound
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The invention provides a preparation method of a formamide compound. A preparation process of the preparation method comprises the following steps: uniformly mixing formic acid and an amine compound raw material selected from primary amine or secondary amine to prepare a homogeneous reaction system; raising the temperature of the homogeneous reaction system to 160 DEG C to 230 DEG C; decomposing the homogeneous reaction system to obtain carbon monoxide and enabling the carbon monoxide to participate in reaction; collecting a reaction product to obtain the formamide compound. The invention provides a novel technology for synthesizing the formamide compound through a heterogeneous method; a catalyst does not need to be used in a reaction process and an operation process is simple and controllable; the selectivity of the amine compound raw material is high.
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Paragraph 0076-0080
(2018/03/24)
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- Iron-Catalyzed Amide Formation from the Dehydrogenative Coupling of Alcohols and Secondary Amines
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The five-coordinate iron(II) hydride complex (iPrPNP)Fe(H)(CO) (iPrPNP = N[CH2CH2(PiPr2)]2) selectively catalyzes the dehydrogenative intermolecular coupling of alcohols and secondary amines to form tertiary amides. This is the most productive base-metal catalyst for dehydrogenative amidation reported to date, in some cases achieving up to 600 turnovers. The catalyst works well for sterically undemanding amines and alcohols or cyclic substrates and is particularly effective in the synthesis of formamides from methanol. However, the catalyst performance declines rapidly with the incorporation of large substituents on the amine or alcohol substrate. Variable-temperature NMR spectroscopic studies suggest that the catalyst resting state is an off-cycle iron(II) methoxide species, (iPrPN(H)P)Fe(H)(OCH3)(CO), resulting from addition of methanol across the Fe-N bond of (iPrPNP)Fe(H)(CO). This reversibly formed iron(II) methoxide complex is favored at mild temperatures but eliminates methanol upon heating.
- Lane, Elizabeth M.,Uttley, Katherine B.,Hazari, Nilay,Bernskoetter, Wesley
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p. 2020 - 2025
(2017/06/13)
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- Photocatalytic N-formylation of amines via a reductive quenching cycle in the presence of air
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Photochemical N-formylation of amines was performed under simple and mild reaction conditions. Amines are common electron donors in reductive photocatalysis, which then typically decompose after donating an electron to the photocatalyst. We have found that these oxidized amines can be utilized to give N-formamides in the presence of air without additional formylating agents. The reaction proceeds via the in situ formation of enamines. Oxygen (air) is necessary for the reaction to occur as it regenerates the photocatalyst forming superoxide radical anions as crucial intermediates involved in the reaction.
- Ghosh, Tamal,Das, Amrita,K?nig, Burkhard
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supporting information
p. 2536 - 2540
(2017/04/03)
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- Catalyst-free: N -formylation of amines using BH3NH3 and CO2 under mild conditions
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The catalyst-free N-formylation of amines using CO2 as the C1 source and BH3NH3 as the reductant has been developed for the first time. The corresponding formylated products of both primary and secondary amines are obtained in good to excellent yields (up to 96% of isolated yield) under mild conditions.
- Zhao, Tian-Xiang,Zhai, Gao-Wen,Liang, Jian,Li, Ping,Hu, Xing-Bang,Wu, You-Ting
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supporting information
p. 8046 - 8049
(2017/07/22)
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- Fluoride-Catalyzed Methylation of Amines by Reductive Functionalization of CO2with Hydrosilanes
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An effective and inexpensive organocatalyst tetrabutylammonium fluoride (TBAF) was developed for the reductive functionalization of CO2with amines to selectively afford formamides or methylamines by employing hydrosilanes. Hydrosilanes with different substituents show discriminatory reducing activity. Thus, the formation of formamides and further reduction products, that is, methylamines could be controlled by elegantly tuning hydrosilane types. Formamides were obtained exclusively under an atmospheric pressure of CO2with triethoxysilane. Using phenylsilane as a reductant, methylamines were attained with up to 99 % yield at 50 °C coupled to a complete deoxygenation of CO2. The crucial intermediate silyl formate in the formylation step was identified and thereby a tentative mechanism involving the fluoride-promoted hydride transfer from the hydrosilane to CO2/formamide was proposed. Striking features of this metal-free protocol are formylation and methylation of amines by reductive functionalization of CO2with hydrosilanes and mild reaction conditions.
- Liu, Xiao-Fang,Ma, Ran,Qiao, Chang,Cao, Han,He, Liang-Nian
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p. 16489 - 16493
(2016/11/09)
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- Solid poly-N-heterocyclic carbene catalyzed CO2 reduction with hydrosilanes
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The utility of solid poly-N-heterocyclic carbene (poly-NHC) materials as organocatalysts for carbon dioxide reduction was studied. These poly-NHC particles were demonstrated to be useful as heterogeneous organocatalysts for the reduction of carbon dioxide to methanol and for the formylation of N–H bonds with hydrosilanes as a hydride donor. These solid catalysts could potentially be useful in large-scale syntheses due to the ease of catalyst recycle and reuse, providing cost savings and environmental sustainability in the long run.
- Riduan, Siti Nurhanna,Ying, Jackie Y.,Zhang, Yugen
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- Selective formylation and methylation of amines using carbon dioxide and hydrosilane catalyzed by alkali-Metal carbonates
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The formylation and methylation of amines with carbon dioxide and hydrosilanes are emerging yet important types of transformations for CO2. Catalytic methods effective for both reactions with wide substrate scopes are rare because of the difficulty in controlling the selectivity. Herein, we report that simple and readily available inorganic bases alkali-metal carbonates, especially cesium carbonatecatalyze both the formylation and methylation reactions efficiently under mild conditions. The selectivity can be conveniently controlled by varying the reaction temperature and silane. A “cesium effect” on both reactions was observed by comparing the catalytic activity of various alkali-metal carbonates. Combined experimental and computational studies suggested the following reaction mechanism: (i) activation of Si?H by Cs2CO3, (ii) insertion of CO2 into Si?H, (iii) formylation of amines by silyl formate, and (iv) reduction of formamides to methylamines.
- Fang, Chi,Lu, Chunlei,Liu, Muhua,Zhu, Yiling,Fu, Yao,Lin, Bo-Lin
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p. 7876 - 7881
(2018/05/23)
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- Iron-catalyzed hydrosilylation of CO2: CO2 conversion to formamides and methylamines
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Catalytic hydrosilylation of CO2 is an efficient and selective approach to form chemicals. Herein, we describe the first iron catalysts able to promote the reductive functionalization of CO2 using hydrosilanes as reductants. Iron(ii) salts supported by phosphine donors enable the conversion of CO2 to formamide and methylamine derivatives under mild reaction conditions. This journal is the Partner Organisations 2014.
- Frogneux, Xavier,Jacquet, Olivier,Cantat, Thibault
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p. 1529 - 1533
(2014/06/09)
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- CO2 as a C1-building block for the catalytic methylation of amines
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A novel catalytic reaction has been designed to utilize, for the first time, CO2 as a C1 feedstock in the synthesis of N-methylamines. Simple zinc catalysts, based on commercially available zinc salts and ligands, prove highly efficient in promoting both a 6 electron reduction of carbon dioxide and the formation of a C-N bond, using hydrosilanes and amines.
- Jacquet, Olivier,Frogneux, Xavier,Das Neves Gomes, Christophe,Cantat, Thibault
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p. 2127 - 2131
(2013/05/21)
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- Melamine trisulfonic acid-catalyzed N-formylation of amines under solvent-free conditions
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A highly convenient method for N-formylation of amines via treatment by formic acid in the presence of melamine trisulfonic acid as a catalyst has been developed. This method showed improvements over previous reports in terms of yield, reaction time and chemoselectivity.
- Yang, Xiao Juan,Zhang, Yong Sen
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p. 2843 - 2848
(2013/07/26)
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- Synthesis of N-formylated β-lactams using nano-sulfated TiO 2 as catalyst under solvent-free conditions
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An easily accessible catalyst, nano-sulfated titania, efficiently catalyzes the N-formylation of β-lactams and all types of amines (primary, secondary, aromatic, and aliphatic) in solvent-free conditions at room temperature.
- Hosseini-Sarvari, Mona,Safary, Ensieh,Jarrahpour, Aliasghar,Heiran, Roghaye
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p. 980 - 987
(2013/02/22)
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- Nano rod-shaped and reusable basic Al2O3 catalyst for N-formylation of amines under solvent-free conditions: A novel, practical and convenient 'NOSE' approach
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An expeditious, simple, highly efficient, practical and green protocol for the N-formylation of alkyl/aryl amines and indole derivatives catalyzed by novel nano rod-shaped basic Al2O3 under solvent-free conditions has been developed. The catalyst is efficiently recycled up to the 5th run, an important point in the domain of green chemistry. The methodology provides cleaner conversion, shorter reaction times and high selectivity which makes the protocol attractive. The Royal Society of Chemistry 2012.
- Das, Vijay Kumar,Devi, Rashmi Rekha,Raul, Prasanta Kumar,Thakur, Ashim Jyoti
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supporting information; experimental part
p. 847 - 854
(2012/04/23)
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- A diagonal approach to chemical recycling of carbon dioxide: Organocatalytic transformation for the reductive functionalization of CO 2
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Lateral thinking: A diagonal approach to CO2 recycling has been explored for the formation of both functionalized and energetic chemicals featuring a reduced carbon center. The strategy relies on the tandem use of a functionalization reagent and a reductant that can be independently modified to access a wide spectrum of chemicals from CO2. It is exemplified with an organocatalytic process to convert CO2 into formamides (see picture).
- Das Neves Gomes, Christophe,Jacquet, Olivier,Villiers, Claude,Thuery, Pierre,Ephritikhine, Michel,Cantat, Thibault
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supporting information; experimental part
p. 187 - 190
(2012/03/26)
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- Recycling of carbon and silicon wastes: Room temperature formylation of N-H bonds using carbon dioxide and polymethylhydrosiloxane
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A highly active organocatalytic system based on N-heterocyclic carbenes has been designed for the formylation of N-H bonds in a large variety of nitrogen molecules and heterocycles, using two chemical wastes: CO2 and polymethylhydrosiloxane (PMHS).
- Jacquet, Olivier,Das Neves Gomes, Christophe,Ephritikhine, Michel,Cantat, Thibault
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supporting information; experimental part
p. 2934 - 2937
(2012/03/27)
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- Direct and efficient synthesis of pyrrole-3-carbaldehydes by Vilsmeier-Haack formylation of pyrroles with sterically crowded amides
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A simple and convenient synthetic method to prepare N-substituted pyrrole-3-carbaldehydes by Vilsmeier-Haack formylation of pyrroles using sterically crowded formamides was developed. The dependence of the formylation regioselectivity on steric features of substrates and reagents is discussed. Georg Thieme Verlag Stuttgart · New York.
- Ilyin, Petrv.,Pankova, Alenas.,Kuznetsov, Mikhail A.
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experimental part
p. 1353 - 1358
(2012/07/03)
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- N-Formylsaccharin: A new formylating agent
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N-Formylsaccharin, a very cheap reagent, has been revealed to be an efficient and chemoselective formylating agent of amines. Georg Thieme Verlag Stuttgart New York.
- Cochet, Thomas,Bellosta, Véronique,Greiner, Alfred,Roche, Didier,Cossy, Janine
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experimental part
p. 1920 - 1922
(2011/10/02)
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- Mild, simple, and efficient method for N-formylation of secondary amines via Reimer-Tiemann reaction
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A rapid and easy route for the N-formylation of secondary amines using chloroform and sodium ethoxide via dichlorocarbene by the Riemer-Tiemann reaction with excellent yield is reported.
- Shastri, Lokesh A.,Shastri, Samundeeswari L.,Bathula, Chinna D.,Basanagouda, Mahantesha,Kulkarni, Manohar V.
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experimental part
p. 476 - 484
(2011/04/17)
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- PKas of the conjugate acids of N-heterocyclic carbenes in water
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pKa values of 19.8-28.2 are reported for the conjugate acids of a large series of NHCs in water. The effects of ring size, N-substituent and C(4)-C(5) saturation on pKa are discussed.
- Higgins, Eleanor M.,Sherwood, Jennifer A.,Lindsay, Anita G.,Armstrong, James,Massey, Richard S.,Alder, Roger W.,O'Donoghue, Annmarie C.
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supporting information; experimental part
p. 1559 - 1561
(2011/03/22)
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- Indium-catalyzed N -formylation of amines under solvent-free conditions
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We have developed a simple, mild method for N-formylation of a wide variety of amines in the presence of indium metal as a catalyst under solvent-free conditions. This reaction is applicable to the chemoselective N-formylation of amino groups and -amino acid esters without epimerization. Georg Thieme Verlag Stuttgart.
- Kim, Joong-Gon,Jang, Doo Ok
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experimental part
p. 1231 - 1234
(2010/07/08)
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- Facile and highly efficient N-formylation of amines using a catalytic amount of iodine under solvent-free conditions
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We developed a simple, practical, and catalytic method for the N-formylation of a wide variety of amines in the presence of molecular iodine as a catalyst under solvent-free conditions. This reaction is applicable to the chemoselective N-formylation of amino groups and -amino acid esters without epimerization.
- Kim, Joong-Gon,Jang, Doo Ok
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experimental part
p. 2093 - 2096
(2010/10/03)
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- ZnO as a new catalyst for N-formylation of amines under solvent-free conditions
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The treatment of amines with formic acid in the presence of ZnO under solvent-free conditions brings about highly and efficient N-formylation to give the corresponding formamides in excellent yields. The N-formylation reaction not only involves mild conditions, simple operation, and high yields but also high chemoselectivity.
- Hosseini-Sarvari, Mona,Sharghi, Hashem
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p. 6652 - 6654
(2007/10/03)
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- Preparation of tetraalkylformamidinium salts and related species as precursors to stable carbenes
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The preparation of a range of tetraalkylformamidinium salts for use as precursors for the formation of stable diamino-and amino-carbenes was discussed. The preparation methods included nucleophilic addition to formamides followed by trapping with electrophiles such as triflic anhydride and various methods of formamide activation. Exchange reactions involving orthoesters, the transamination of amidinium salts and alkylation methods were other methods suitable for the synthesis.
- Alder, Roger W.,Blake, Michael E.,Bufali, Simone,Butts, Craig P.,Guy Orpen,Schuetz, Jan,Williams, Stuart J.
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p. 1586 - 1593
(2007/10/03)
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- 4-Oxa and 4-thia steroids
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The compounds of the present invention are those of structural formula (I) STR1 wherein X is oxygen or sulfur. Pharmaceutical compositions and methods of use of the compounds in the treatment of hyperandrogenic conditions are disclosed. In addition, the combination of the compounds with other active agents such as finasteride, minoxidil and retinoic acid or a derivative thereof is disclosed.
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- Radical cations of trialkylamines: ESR spectra and structures
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Novel syntheses of cyclopropyldiisopropylamine (15), di-tert- butylcyclopropylamine (16), dicyclopropylisopropylamine (17), and tricyclopropylamine (18) are described. Hyperfine data were determined by ESR spectroscopy for the radical cations of these trialkylamines, as well as for those of ethyldiisopropylamine (10), diisopropyl-n-propylamine (11), dicyclohexylethylamine (12), diisopropyl-3-pentylamine (14), and 1- azabicyclo[3.3.3]undecane (manxine; 27). The radical cation of triisopropylamine (13) was reexamined under conditions of improved spectral resolution. Coupling constants of the 14N nucleus and the β-protons in the radical cations of 18 trialkylamines provide reliable information about the geometries of these species, which are confirmed by theoretical calculations. With the exception of a few oligocyclic amines, for which flattening is impaired by the rigid molecular framework, all of the radical cations should be planar. Correlation between the observed coupling constants of the β- protons and the calculated 2 θ> values of the dihedral angle θ, defining the conformation of the alkyl substituent or the azacycloalkane, is verified. Upon oxidation, striking changes occur for those amines that have cyclopropyl substituents, because of the tendency of these groups to assume a perpendicular conformation in the neutral amines and a bisected orientation in the corresponding radical cations.
- De Meijere, Armin,Chaplinski, Vladimir,Gerson, Fabian,Merstetter, Pascal,Haselbach, Edwin
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p. 6951 - 6959
(2007/10/03)
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- Solvent effect in the ruthenium catalyzed carbonylation of amines. Selective synthesis of dialkylformamides
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Formamides are selectively produced in the ruthenium-catalyzed carbonylation of amines in alcoholic solvents.The process is shown to occur sequentially via initial carbonylation of the alcohol to yield the corresponding formate, which then reacts with the amine to yield the formamide.The method is of interest for the carbonylation of unreactive amines (aniline, t-butylamine).
- Bitsi, G.,Jenner, G.
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p. 429 - 436
(2007/10/02)
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- DECOMPOSITION OF ALKOXYL RADICALS IN THE SOLID PHASE AT LOW TEMPERATURES
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The dissociation of photolytically generated alkoxyl radicals, formed during the homolysis of a series of peroxides, at low temperatures was investigated as a function of their structure by ESR and GLC.On the basis of the experimental data an assessment was made of the relative stability of the alkoxyl radicals.Analysis of the electronic structure of tert-butoxyl and trimethylsiloxyl radicals, made in the INDO approximation, showed that the direction of dissociation is due to the different strengths of the C - C bonds in the tert-butoxyl radical and the Si - C bonds in the trimethylsiloxyl radical.
- Luk'yanenko, L. V.,Petrenko, V. V.,Turovskii, A. A.,Turovskii, N. A.
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p. 613 - 615
(2007/10/02)
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