- Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
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Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
- Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
-
supporting information
p. 13122 - 13135
(2021/08/31)
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- Deoxygenation of primary amides to amines with pinacolborane catalyzed by Ca[N(SiMe3)2]2(THF)2
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Deoxygenative reduction of amides is a challenging but favorable synthetic method of accessing amines. In the presence of a catalytic amount of Ca[N(SiMe3)2]2(THF)2, pinacolborane (HBpin) could efficiently reduce a broad scope of amides, primary amides in particular, into corresponding amines. Functional groups and heteroatoms showed good tolerance in this process of transformation, and a plausible reaction mechanism was proposed.
- Gong, Mingliang,Guo, Chenjun,Jiang, Linhong,Luo, Yunjie,Yu, Chong
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supporting information
p. 1201 - 1206
(2021/05/29)
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
-
A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
-
supporting information
p. 9204 - 9207
(2021/09/20)
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- Base-Catalyzed Hydrosilylation of Nitriles to Amines and Esters to Alcohols
-
Base-catalyzed hydrosilylation of nitriles to amines and esters to silylated alcohols is reported. This protocol tolerates electron-rich and electron-neutral olefins and works in the presence of basic functional groups (e. g. tertiary amines) but fails for acidic substrates, such as phenols and NH anilines. This catalytic system does not tolerate carbonyl groups, such as aldehydes, ketones, esters and carbamides, which are reduced to corresponding alcohols and amines. With the exact amount of silane, esters can be selectively reduced in the presence of nitriles, but the selectivity drops for the pairs ester/carboxamide and carboxamide/nitrile. Through competition experiments, the following preference in functional group reactivity was determined: ester > carboxamide > nitrile.
- Clarke, Joshua A.,Nikonov, Georgii I.,van der Est, Art
-
supporting information
p. 4434 - 4439
(2021/08/30)
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- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 1618 - 1629
(2021/01/25)
-
- Green method for catalyzing reduction reaction of aliphatic nitro derivative
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The invention relates to a green method for catalyzing reduction reaction of aliphatic nitro derivatives. According to the method, non-transition metal compounds, namely triethyl boron and potassium tert-butoxide, are used as a catalytic system for the first time, an aliphatic nitro derivative and pinacolborane which is low in price and easy to obtain are catalyzed to be subjected to a reduction reaction under mild conditions, and an aliphatic amine hydrochloride product is synthesized after acidification with a hydrochloric acid aqueous solution. Compared with a traditional method, the method generally has the advantages that the catalyst is cheap and easy to obtain, operation is convenient, and reaction is safe. The selective reduction reaction of the aliphatic nitro derivative catalyzed by the non-transition metal catalyst and pinacol borane is realized for the first time, and the aliphatic amine hydrochloride product is synthesized through acidification treatment of the hydrochloric acid aqueous solution, so that a practical new reaction strategy is provided for laboratory preparation or industrial production.
- -
-
Paragraph 0005-0006; 0073-0076
(2021/07/31)
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- Metal-Free Synthesis of Heteroaryl Amines or Their Hydrochlorides via an External-Base-Free and Solvent-Free C-N Coupling Protocol
-
Herein, a metal-free and solvent-free protocol was developed for the C-N coupling of heteroaryl halides and amines, which afforded numerous heteroaryl amines or their hydrochlorides without any external base. Further investigations elucidated that the basicity of amines and specific interactions derived from the X-ray crystallography analysis of 3j′·HCl played pivotal roles in the reactions. Moreover, this protocol was scalable to gram scales and applicable to drug molecules, which demonstrated its practical value for further applications.
- Fan, Guang-Gao,Jiang, Bo-Wen,Sang, Wei,Cheng, Hua,Zhang, Rui,Yu, Bao-Yi,Yuan, Ye,Chen, Cheng,Verpoort, Francis
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p. 14627 - 14639
(2021/11/01)
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- Transition metal-free catalytic reduction of primary amides using an abnormal NHC based potassium complex: Integrating nucleophilicity with Lewis acidic activation
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An abnormal N-heterocyclic carbene (aNHC) based potassium complex was used as a transition metal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions. Only 2 mol% loading of the catalyst exhibits a broad substrate scope including aromatic, aliphatic and heterocyclic primary amides with excellent functional group tolerance. This method was applicable for reduction of chiral amides and utilized for the synthesis of pharmaceutically valuable precursors on a gram scale. During mechanistic investigation, several intermediates were isolated and characterized through spectroscopic techniques and one of the catalytic intermediates was characterized through single-crystal XRD. A well-defined catalyst and isolable intermediate along with several stoichiometric experiments, in situ NMR experiments and the DFT study helped us to sketch the mechanistic pathway for this reduction process unravelling the dual role of the catalyst involving nucleophilic activation by aNHC along with Lewis acidic activation by K ions.
- Bhunia, Mrinal,Sahoo, Sumeet Ranjan,Das, Arpan,Ahmed, Jasimuddin,Sreejyothi,Mandal, Swadhin K.
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p. 1848 - 1854
(2020/03/03)
-
- Silicon hydrogenation reaction method of organic boron and inorganic alkali catalysis amide (by machine translation)
-
The method is characterized in that organic boron and inorganic bases are used as catalysts, silane is used as a reducing agent, primary amide is reduced to primary amine or dehydration dinitrile, the secondary amide is reduced to a secondary amine or aldimine, and the tertiary amide is reduced to tertiary amine. The method has the advantages of simple operation, mild reaction conditions, wide substrate universality, good functional group compatibility and the like, and has the characteristics of good stability, cheap and accessible catalyst, simple and convenient operation, high practicality and the like. (by machine translation)
- -
-
Paragraph 0134-0140; 0146-0149
(2020/08/18)
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- Synthesis of Molybdenum Pincer Complexes and Their Application in the Catalytic Hydrogenation of Nitriles
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A series of molybdenum(0), (I) and (II) complexes ligated by different PNP and NNN pincer ligands were synthesized and structurally characterized. Along with previously described Mo?PNP complexes Mo-1 and Mo-2, all prepared compounds were tested in the catalytic hydrogenation of aromatic nitriles to primary amines. Among the applied catalysts, Mo-1 is particularly well suited for the hydrogenation of electron-rich benzonitriles. Additionally, two aliphatic nitriles were transformed into the desired products in 80 and 86 percent, respectively. Moreover, catalytic intermediate Mo-1a was isolated and its role in the catalytic cycle was subsequently demonstrated.
- Leischner, Thomas,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
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p. 4543 - 4549
(2020/07/13)
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- Catalytic Hydroboration of Organic Nitriles Promoted by Aluminum Complex
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We demonstrate an efficient protocol for the chemoselective hydroboration of organic nitriles with pinacolborane (HBpin) and catecholborane (HBcat) using aluminum alkyl complex [κ2-{2-F?C6H4NP(Se)Ph2}2Al?(Me)] as a pre-catalyst to afford diboryl amines under solvent-free and mild conditions (60 °C) in high yield. The aluminum complex was prepared by the reaction of [2-F?C6H4NHP(Se)Ph2] and trimethylaluminum in toluene. The solid-state structure of Al complex is established. Nitriles with a wide array of electron-withdrawing and electron-donating functional groups were easily converted to the desired products through the formation of aluminum hydride as an active species. A kinetic study of the catalytic reaction is also reported. (Figure presented.).
- Harinath, Adimulam,Bhattacharjee, Jayeeta,Panda, Tarun K.
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supporting information
p. 850 - 857
(2019/01/04)
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- Efficient and chemoselective hydroboration of organic nitriles promoted by TiIV catalyst supported by unsymmetrical acenaphthenequinonediimine ligand
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We report the synthesis, characterization, and utilization of a titanium (IV) complex [(η5-C5H5){L}TiCl2] (1) supported by a monoanionic ligand (L), N-(2, 6-diisopropyl)acenaphthenequinonediimido, as a molecular pre-catalyst for the hydroboration of nitriles. The unsymmetrical N-silylated N-(2, 6-diisopropyl)-N-(trimethylsilyl)-acenaphthenequinonediimine ligand (LSiMe3) was obtained upon the completion of a one-pot reaction between N-(2, 6-diisopropyl)iminoacenaphthenone and lithium hexamethyldisilazide in the presence of trimethylsilyl chloride in 1:1:1 M ratio at 90 °C. The reaction of LSiMe3 with {η5-(C5H5)TiCl3) in equal proportion (1:1) at 60 °C afforded the titanium complex [(η5-C5H5){L}TiCl2] (1) in good yield. The molecular structures of the N-silyl ligand (LSiMe3) and Ti(IV) complex 1 were established by single-crystal X-ray analysis. Complex 1 was tested as a pre-catalyst for hydroboration of nitriles with pinacolborane (HBpin) and catecholborane (HBcat) to afford diboryl amines at ambient temperature. Titanium complex 1 exhibited high conversion, superior selectivity, and broad functional group tolerance during hydroboration of nitriles with both HBpin and HBcat under mild conditions.
- Banerjee, Indrani,Anga, Srinivas,Bano, Kulsum,Panda, Tarun K.
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supporting information
(2019/10/14)
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- A BEt3-Base catalyst for amide reduction with silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
-
-
- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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p. 6084 - 6093
(2019/05/24)
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- Primary amides to amines or nitriles: A dual role by a single catalyst
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We report a manganese-catalyzed hydrosilylative reduction of various primary amides to amines (25 examples). On simple modification of the reaction conditions such as in the presence of a catalytic amount of secondary amide, the same catalyst can transform the primary amides into intermediate nitrile compounds (16 examples) in excellent yields. This is the first example where such a controlled catalytic transformation of primary amides to amines or nitriles with a single catalyst has been demonstrated.
- Das, Hari S.,Das, Shyamal,Dey, Kartick,Singh, Bhagat,Haridasan, Rahul,Das, Arpan,Ahmed, Jasimuddin,Mandal, Swadhin K.
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supporting information
p. 11868 - 11871
(2019/10/11)
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- Old Concepts, New Application – Additive-Free Hydrogenation of Nitriles Catalyzed by an Air Stable Alkyl Mn(I) Complex
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An efficient additive-free manganese-catalyzed hydrogenation of nitriles to primary amines with molecular hydrogen is described. The pre-catalyst, a well-defined bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dpre)(CO)3(CH3)] (dpre=1,2-bis(di-n-propylphosphino)ethane), undergoes CO migratory insertion into the manganese-alkyl bond to form acyl complexes which upon hydrogenolysis yields the active coordinatively unsaturated Mn(I) hydride catalyst [Mn(dpre)(CO)2(H)]. A range of aromatic and aliphatic nitriles were efficiently and selectively converted into primary amines in good to excellent yields. The hydrogenation of nitriles proceeds at 100 °C with a catalyst loading of 2 mol % and a hydrogen pressure of 50 bar. Mechanistic insights are provided by means of DFT calculations. (Figure presented.).
- Weber, Stefan,Veiros, Luis F.,Kirchner, Karl
-
supporting information
p. 5412 - 5420
(2019/11/13)
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- Liquid-phase hydrogenation of nitriles to amines facilitated by a co(ii)/zn(0) pair: a ligand-free catalytic protocol
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The given report introduces a simple and user-friendly in situ method for the production of catalytically active cobalt particles. The approach circumvents the use of air-and moisture-sensitive reductants as well as the application of anhydrous Co-precursor salts. Accordingly, the described catalytic system is readily assembled under open-flask conditions by simply combining the components in the reaction vessel. Therefore, the arduous charging procedure of the reaction autoclave in a glovebox under an inert gas atmosphere is no longer necessary. In fact, the catalytically active material is obtained upon treatment of readily available Co(OAc)2·4 H2O with benign commercial Zn powder. The catalytic performance of the resultant material was tested in the heterogeneous hydrogenation of nitriles to the corresponding primary amines. Both activity and selectivity of the cobalt catalyst are significantly enhanced if a triflate-based Lewis acid and ammonia is added to the reaction mixture.
- Timelthaler, Daniel,Topf, Christoph
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p. 11604 - 11611
(2019/10/02)
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- Catalytic Reduction of Nitriles by Polymethylhydrosiloxane Using a Phenalenyl-Based Iron(III) Complex
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The reduction of nitriles to primary amines using an inexpensive silane such as polymethylhydrosiloxane (PMHS) is an industrially important reaction. Herein we report the synthesis of an earth-abundant Fe(III) complex bearing a phenalenyl-based ligand that was characterized by mass spectroscopy, elemental analysis, cyclic voltammetry, and single-crystal X-ray diffraction. The complex showed excellent catalytic activity toward reduction of aromatic, heteroaromatic, aliphatic, and sterically crowded nitriles to produce primary amines using polymethylhydrosiloxane (PMHS).
- Das, Shyamal,Das, Hari Sankar,Singh, Bhagat,Haridasan, Rahul Koottanil,Das, Arpan,Mandal, Swadhin K.
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supporting information
p. 11274 - 11278
(2019/09/10)
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- Synthesis of cobalt nanoparticles by pyrolysis of Vitamin B12: A non-noble-metal catalyst for efficient hydrogenation of nitriles
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A facile preparation of vitamin B12-derived carbonaceous cobalt particles supported on ceria is reported. The resulting composite material is obtained upon wet impregnation of ceria with natural cyanocobalamin and consecutive pyrolysis under inert conditions. The novel catalyst shows good to excellent performance in the industrially relevant heterogeneous hydrogenation of nitriles to the corresponding primary amines.
- Ferraccioli, Raffaella,Borovika, Diana,Surkus, Annette-Enrica,Kreyenschulte, Carsten,Topf, Christoph,Beller, Matthias
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p. 499 - 507
(2018/02/07)
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- Switching the Selectivity of Cobalt-Catalyzed Hydrogenation of Nitriles
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Previous studies of base metals for catalytic hydrogenation of nitriles to primary amines or secondary aldimines focus on designing complexes with elaborate structures. Herein, we report "twin" catalytic systems where the selectivity of nitrile hydrogenation can be tuned by including or omitting the ligand HN(CH2CH2PiPr2)2 (iPrPNHP). Simply treating CoBr2 with NaHBEt3 generates cobalt particles, which can catalyze the hydrogenation of nitriles to primary amines with high selectivity and broad functional group tolerance. Ligating CoBr2 with iPrPNHP followed by the addition of NaHBEt3, however, forms a homogeneous catalyst favoring secondary aldimines for both hydrogenation and hydrogenative coupling of benzonitrile.
- Dai, Huiguang,Guan, Hairong
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p. 9125 - 9130
(2018/09/21)
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- Hydrogenation of Nitriles and Ketones Catalyzed by an Air-Stable Bisphosphine Mn(I) Complex
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Efficient hydrogenations of nitriles and ketones with molecular hydrogen catalyzed by a well-defined bench-stable bisphosphine Mn(I) complex are described. These reactions are environmentally benign and atomically economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. A range of aromatic and aliphatic nitriles and ketones were efficiently converted into primary amines and alcohols, respectively, in good to excellent yields. The hydrogenation of nitriles proceeds at 100 °C with catalyst loading of 2 mol % and 20 mol % base (t-BuOK), while the hydrogenation of ketones takes place already at 50 °C, with a catalyst loading of 1 mol % and 5 mol % of base. In both cases, a hydrogen pressure of 50 bar was applied.
- Weber, Stefan,St?ger, Berthold,Kirchner, Karl
-
supporting information
p. 7212 - 7215
(2018/11/25)
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- N-N bond formation in Ugi processes: from nitric acid to libraries of nitramines
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The Ugi reaction has drawn considerable attention over the years leading to numerous libraries of heterocycles and various extensions changing the nature of the components of the coupling. We report here the use of nitric acid as carboxylic acids surrogates, displaying the first aminative Ugi-type reaction leading to nitramines.
- Mercalli, Valentina,Nyadanu, Aude,Cordier, Marie,Tron, Gian Cesare,Grimaud, Laurence,El Kaim, Laurent
-
supporting information
p. 2118 - 2121
(2017/02/19)
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- Exhaustive Chemoselective Reduction of Nitriles by Catalytic Hydrosilylation Involving Cooperative Si-H Bond Activation
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A chemoselective method for the catalytic hydrosilylation of nitriles to either the imine or amine oxidation level is reported. The chemoselectivity is controlled by the hydrosilane used. The usefulness of the nitrile-to-amine reduction is demonstrated for a diverse set of aromatic and aliphatic nitriles, and the amines are easily isolated after hydrolysis as their hydrochloride salts. This exhaustive nitrile reduction proceeds at room temperature.
- Wübbolt, Simon,Oestreich, Martin
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supporting information
p. 2411 - 2414
(2017/10/03)
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- Rapid Continuous Ruthenium-Catalysed Transfer Hydrogenation of Aromatic Nitriles to Primary Amines
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A continuous flow method for the selective reduction of aromatic nitriles to the corresponding amine is reported. The method is based on a ruthenium-catalysed transfer-hydrogenation process, requires no additives, and uses isopropanol as both solvent and reducing agent. The process utilizes 1 mol% of the commercially available [Ru(p -cymene)Cl 2 ] 2, with a residence time of ca. 9 min, and a throughput of 50 mmol/h. The method was successfully applied to a range of aromatic nitriles providing the corresponding primary amines in good yields.
- Labes, Ricardo,González-Calderón, Davir,Battilocchio, Claudio,Mateos, Carlos,Cumming, Graham R.,De Frutos, Oscar,Rincón, Juan A.,Ley, Steven V.
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supporting information
p. 2855 - 2858
(2017/10/06)
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- Direct cycle between co-product and reactant: An approach to improve the atom economy and its application in the synthesis and protection of primary amines
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Two important goals of green chemistry are to maximize the efficiency of reactants and to minimize the production of waste. In this study, a novel approach to improve the atom economy of a chemical process was developed by incorporating a direct cycle between a co-product and a reactant of the same reaction. To demonstrate this concept, recoverable 3,4-diphenylmaleic anhydride (1) was designed and used for the atom-economical synthesis of aliphatic primary amines from aqueous ammonia. In each individual cycle, only ammonia and alkyl halide were consumed, and 1 was recovered in nearly a quantitative yield. In this approach for developing atom-economical protecting agents, 1 showed good performance as a recoverable protecting agent for primary amines. The broad substrate scope, good tolerance to various reaction conditions, and high reaction and recovery rates make 1 a valuable complement to conventional primary amine protecting agents.
- Guan, Qi,Jiang, Mingyang,Wu, Junhui,Zhai, Yanpeng,Wu, Yue,Bao, Kai,Zhang, Weige
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supporting information
p. 5794 - 5799
(2016/11/06)
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- A method for the production of primary amines
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The invention relates to the field of chemical industry and particularly relates to a method for preparing primary amine by using the raw materials including halogenated hydrocarbon (or hydrocarbon alcohol sulfonate) and ammonia water (or formamide). The method comprises the following three steps: (1) imidization: 3,4-diarylfuran-2,5-diketone (I) reacts with ammonia (or formamide) and the like to obtain 3,4-diaryl-1H-pyrrole-2,5-diketone (II); (2) N-hydrocarbylation: 3,4-diaryl-1H-pyrrole-2,5-diketone (II) generates an N-hydrocarbylation reaction with halogenated hydrocarbon (or hydrocarbon alcohol sulfonate) in the presence of alkali to obtain N-hydrocarbyl-3,4-diaryl-1H-pyrrole-2,5-diketone (III); and (3) hydrolysis: N-hydrocarbyl-3,4-diaryl-1H-pyrrole-2,5-diketone (III) is subjected to alkali hydrolysis to obtain primary amine and the generated 2,3-diaryl maleate is subjected to acid treatment and automatic ring closing to form 3,4-diaryl furan-2,5-diketone (I) which is subjected to imidization and directly applied to the N-hydrocarbylation reaction. The method provided by the invention has the characteristics that the 3,4-diaryl furan-2,5-diketone can be circularly used at a high recovery rate, the molar ratio of the raw materials is low, and the yield of the product primary amine is high.
- -
-
Paragraph 0091; 0092; 0242; 0243
(2016/10/09)
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- Optimum bifunctionality in a 2-(2-pyridyl-2-ol)-1,10-phenanthroline based ruthenium complex for transfer hydrogenation of ketones and nitriles: Impact of the number of 2-hydroxypyridine fragments
-
Considerable differences in reactivity and selectivity for 2-hydroxypyridine (2-HP) derived ruthenium complexes in transfer hydrogenation are described. Bifunctional Ru(ii)-(phenpy-OH) [phenpy-OH: 2-(2-pyridyl-2-ol)-1,10-phenanthroline] complex (2) exhibited excellent catalytic activity in transfer hydrogenation (TH) of ketones and nitriles. Notably, in comparison with all the reported 2-hydroxypyridine (2-HP) derived ruthenium complexes in transfer hydrogenation, complex 2 displayed significantly higher activity. Additionally, exploiting the metal-ligand cooperativity in complex 2, chemoselective TH of ketones was achieved and sterically demanding ketones were readily reduced. An outer-sphere mechanism is proposed for this system as exogenous PPh3 has no significant effect on the rate of this reaction. This is a rare example of a highly active bifunctional Ru(ii) catalyst bearing only one 2-HP unit.
- Paul, Bhaskar,Chakrabarti, Kaushik,Kundu, Sabuj
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p. 11162 - 11171
(2016/07/16)
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- A proton-switchable bifunctional ruthenium complex that catalyzes nitrile hydroboration
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A new bifunctional pincer ligand framework bearing pendent proton-responsive hydroxyl groups was prepared and metalated with Ru(II) and subsequently isolated in four discrete protonation states. Stoichiometric reactions with H2 and HBPin showed facile E-H (E = H or BPin) activation across a Ru(II)-O bond, providing access to unusual Ru-H species with strong interactions with neighboring proton and boron atoms. These complexes were found to promote the catalytic hydroboration of ketones and nitriles under mild conditions, and the activity was highly dependent on the ligand's protonation state. Mechanistic experiments revealed a crucial role of the pendent hydroxyl groups for catalytic activity.
- Geri, Jacob B.,Szymczak, Nathaniel K.
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supporting information
p. 12808 - 12814
(2015/10/28)
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- Hydrogenation of Aliphatic and Aromatic Nitriles Using a Defined Ruthenium PNP Pincer Catalyst
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Selective catalytic reductions of nitriles are presented using the commercially available Ru-Macho-BH complex. A variety of aliphatic, aromatic and (hetero)cyclic nitriles including industrially important adipodinitrile are hydrogenated to the corresponding primary amines. Modelling suggests the reaction follows an outer sphere hydrogenation mechanism. An efficient and selective catalytic reduction of nitriles is presented using the commercially available Ru-Macho-BH complex. A variety of aliphatic, aromatic and (hetero)cyclic nitriles including the industrially important adipodinitrile are hydrogenated to the corresponding primary amines. The reaction follows an outer-sphere mechanism.
- Neumann, Jacob,Bornschein, Christoph,Jiao, Haijun,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 5944 - 5948
(2015/09/22)
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- 1,2,3-Trimethoxypropane, a glycerol-based solvent with low toxicity: New utilization for the reduction of nitrile, nitro, ester, and acid functional groups with TMDS and a metal catalyst
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1,2,3-Trimethoxypropane (1,2,3-TMP) was prepared from glycerol in one step in good yield and selectivity by phase transfer catalysis. According to OECD guidelines, a toxicity study was realized for this compound. It revealed that 1,2,3-TMP has a low acute toxicity, no skin sensitization, no mutagenicity and no ecotoxicity in an aquatic environment. This compound was also used as a solvent for the reduction of organic functions using either aluminium hydride or 1,1,3,3-tetramethyldisiloxane (TMDS) as a benign hydride source. In particular, a new process for the reduction of nitriles to amines in 2-MeTHF and in 1,2,3-TMP was developed, using TMDS in combination with copper triflate (Cu(OTf)2).
- Sutter, Marc,Pehlivan, Leyla,Lafon, Romain,Dayoub, Wissam,Raoul, Yann,Metay, Estelle,Lemaire, Marc
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supporting information
p. 3020 - 3026
(2013/11/06)
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- TBAF-catalyzed hydrosilylation for the reduction of aromatic nitriles
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The selective catalytic hydrosilylation of functional groups is becoming an interesting tool for organic synthesis. In the present study, fluoride-catalyzed hydrosilylations of aromatic nitriles have been examined in detail. Using catalytic amounts of inexpensive tetra-n-butylammonium fluoride (TBAF) various aromatic nitriles are reduced in good yields under mild conditions.
- Bornschein, Christoph,Werkmeister, Svenja,Junge, Kathrin,Beller, Matthias
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supporting information
p. 2061 - 2065
(2013/10/08)
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- Selective ruthenium-catalyzed transfer hydrogenations of nitriles to amines with 2-butanol
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Transfer your hydrogen: Fast and general transfer hydrogenation of nitriles to form primary amines is possible with a homogeneous Ru/1,4- bis(diphenylphosphino)butane (DPPB) catalyst (see scheme). The use of 2-butanol as the hydrogen-transfer reagent is essential for the selective reduction of aromatic, heteroaromatic, and aliphatic nitriles with this system. Copyright
- Werkmeister, Svenja,Bornschein, Christoph,Junge, Kathrin,Beller, Matthias
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supporting information
p. 4437 - 4440
(2013/04/23)
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- A catalytic version of hypervalent aryl-λ3-iodane-induced Hofmann rearrangement of primary carboxamides: Iodobenzene as an organocatalyst and m-chloroperbenzoic acid as a terminal oxidant
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The first catalytic version of hypervalent aryl-λ3- iodane-induced Hofmann rearrangement of primary carboxamides, which probably involves in situ generation of a tetracoordinated bis(aqua)(hydroxy)phenyl- λ3-iodane complex as an active oxidant from a catalytic amount of iodobenzene by the reaction with m-chloroperbenzoic acid in the presence of HBF4 in dichloromethane-water under mild conditions, was developed.
- Miyamoto, Kazunori,Sakai, Yuuta,Goda, Shunsuke,Ochiai, Masahito
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supporting information; experimental part
p. 982 - 984
(2012/02/04)
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- Synthesis and antimicrobial activity of N1-benzyl or N 1-benzyloxy-1,6-dihydro-1,3,5-triazine-2,4-diamines
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The emergence and spread of multidrug-resistant strains of Staphylococcus aureus and Mycobacterium tuberculosis are generating a threat to public health worldwide. In the current study, a series of N1-benzyl and N 1-benzyloxy-1,6-dihydro-1,3,5-triazine-2,4-diamine derivatives were synthesized and investigated for their antimicrobial activity against S. aureus, and Mycobacterium smegmatis which is taxonomically related to M. tuberculosis. Most of the compounds exhibited good activity against M. smegmatis as determined by comparison of diameters of the zone of inhibition of test compounds and standard antibiotics. Compound 7o showed potent antimycobacterial activity against M. smegmatis without mammalian DHFR inhibition liability. The results from this study indicate that 1-benzyl derivatives of 1,6-dihydro-1,3,5- triazine-2,4-diamines may be used as lead compounds for the discovery of antimycobacterial agents.
- Ma, Xiang,Tan, Soo-Tong,Khoo, Chai-Ling,Sim, Hong-May,Chan, Lai-Wah,Chui, Wai-Keung
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supporting information; experimental part
p. 5428 - 5431
(2011/10/12)
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- A novel efficient and chemoselective method for the reduction of nitriles using the system silane/oxo-rhenium complexes
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This work reports the reduction of nitriles to the corresponding primary amines with silanes catalyzed by oxo-rhenium complexes. The catalytic system PhSiH3/ReIO2(PPh3)2 (10 mol %) reduced efficiently a series of nitriles in the presence of a wide range of functional groups such as -Cl, -F, -Br, -I, -CF3, -OCH3, -SCH3, -SO2CH3 and -NHTs.
- Cabrita, Ivania,Fernandes, Ana C.
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experimental part
p. 8183 - 8186
(2011/10/31)
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- Versatile Reagent for Reduction of Azides to Amines
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Triphenylphosphine (TPP) in refluxing methanol effectively reduces a variety of azides 1a-k to amines 2a-k in very good yields.
- Pal, Bikash,Jaisankar, Parasuraman,Giri, Venkatachalam S.
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p. 1317 - 1323
(2007/10/03)
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- Biguanide derivatives, manufacturing method thereof, and disinfectants containing the derivatives
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The invention presents a biguanide derivative or its salt expressed by a formula: STR1 (where R1 and R2 are as defined in Specification), or formula: STR2 (where A and R3 is as defined in specification). This biguanide derivative or its salt is preferably used as the effective amount of a disinfectant for humans, animals, medical appliances, etc.
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- 3(2H)pyridazinone, process for its preparation and anti-allergic agent containing it
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A 3(2H)pyridazinone of the formula: STR1 wherein R1 is C2 -C5 alkyl; R2 is hydrogen, C1 -C3 alkyl, chlorine or bromine; R3 is hydrogen or C1 -C4 alkyl; and each of Y1, Y2 and Y3 which may be the same or different, is hydrogen, C1 -C8 alkyl, C2 -C8 alkenyl, halogen, --(CH2)l A [wherein A is substituted amino of the formula --N(R4) (R5) (wherein each of R4 and R5 which may be the same or different, is C1 -C4 alkyl, or R4 and R5 together form C4 -C6 alkylene), morpholino, 4-R6 -piperazin-1-yl (wherein R6 is C1 -C3 alkyl) or --OR7 (wherein R7 is hydrogen or C1 -C3 alkyl), and l is an integer of 0 to 3], --OR8 [wherein R8 is hydrogen, C1 -C8 alkyl, C3 -C5 alkenyl, benzyl or --(CH2)q --R9 [wherein R9 is CO2 R3 (wherein R3 is as defined above), --CONHR3 (wherein R3 is as defined above) or --CH2 OR7 (wherein R7 is as defined above), and q is an integer of 1 to 5]], --CO2 R3 (wherein R3 is as defined above), --CON(R10) (R11) [wherein each of R10 and R11 which may be the same or different, is hydrogen, C1 -C4 alkyl or C3 -C5 alkenyl, or R10 and R11 together form C4 -C6 alkylene, --(CH2)2 O(CH2)2 -- or --(CH2)2 N(R6)(CH2)2 -- (wherein R6 is as defined above)], --CONH(CH2)m A (wherein A is as defined above, and m is an integer of 2 to 4), --CH=CHCOR12 (wherein R12 is hydroxy, C1 -C4 alkoxy or --N(R13) (CH2)n CO2 R3 (wherein R13 is hydrogen, C1 -C6 alkyl or cycloalkyl, R3 is as defined above, and n is an integer of 1 to 4)), --SR14 (wherein R14 is C1 -C4 alkyl), --CN or STR2 wherein R3 is as defined above), or two of Y1, Y2 and Y3 together form STR3 (wherein p is an integer of 1 or 2), and a pharmaceutically acceptable salt thereof.
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- Substituent effects. 14. Anomalous dissociation constants in water-organic solvent mixtures: benzylammonium ions and related systems
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Thermodynamic dissociation constants in various water-organic solvent mixtures are given for benzylammonium, benzyldialkylammonium, and (2-phenylethyl)ammonium ions.Deviations from the Hammett equation (Eqn. 1) are similar to those observed for carboxylic acids, but of opposite sign.The extended Hammett equation (Eqn. 3), containing the hydrophobic constant, ?, yields good correlations.Derived secondary normal sigma values are exemplified.
- Hoefnagel, A. J.,Vos, R. H. de,Wepster, B. M.
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- 3(2H)Pyridazinone, process for its preparation and anti-allergic agent containing it
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A 3(2H)pyridazinone of the formula: STR1 wherein R1 is hydrogen, methyl, C3 -C6 alkenyl, C5 or C6 cycloalkyl, benzyl, phenyl, --(CH2)m CO2 R3 (wherein R3 is hydrogen or C1 -C5 alkyl, and m is an integer of from 1 to 4), --(CH2)n A (wherein A is --OH or --N(R4)2 wherein R4 is C1 -C3 alkyl, and n is an integer of from 2 to 6) or --CH2 CF3 ; R2 is chlorine or bromine; each of Y1 and Y2 which may be the same or different, is hydrogen, C1 -C5 alkyl, C2 -C8 alkenyl, halogen, --OR5 (wherein R5 is hydrogen, C1 -C8 alkyl or STR2 wherein q is an integer of from 1 to 4), --CO2 R6 (wherein R6 is hydrogen or C1 -C5 alkyl), --N(R7)2 (wherein R7 is C1 -C4 alkyl) or --SR8 (wherein R8 is C1 -C4 alkyl); and Y3 is C1 -C5 alkyl, C2 -C8 alkenyl, halogen, --OR5 (wherein R5 is as defined above), --CO2 R6 (wherein R6 is as defined above), --N(R7)2 (wherein R7 is as defined above) or --SR8 (wherein R8 is as defined above), or a pharmaceutically acceptable salt thereof.
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- An Unusual Fischer Indole Synthesis with 4-Keto Acids: An Indole Incorporating the Terminal Hydrazine Nitrogen
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During preparation of a pharmaceutically active, N-benzylated indole derivative from 4-keto acid and N1-benzylated phenylhydrazine precursors, the N-unsubstituted indole analogue arose as a significant byproduct.The proportion of debenzylated indole was greater with α-alkylated rather than straight-chain keto acids and the byproduct was fully suppressed when a keto ester was substituted for the keto acid.The benzylic group was shown to have eliminated as the amine and 15N label incorporation demonstrated terminal phenylhydrazine nitrogen incorporation in the indole byproduct only, an exception to the usual course of the Fischer indolization reaction.A ring-chain equilibration in the ketimino acid intermediate is proposed to account for the competing pathway.
- Conn, Robin S. Eichen,Douglas, Alan W.,Karady, Sandor,Corley, Edward G.,Lovell, Alfred V.,Shinkai, Ichiro
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p. 2908 - 2913
(2007/10/02)
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