- Design, Synthesis and Antifungal Evaluation of N-Substituted-1-(3-chloropyridin-2-yl)-N-(pyridin-4-yl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxamide Derivatives
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A series of 1-(3-chloropyridin-2-yl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxamide derivatives which have di-substituents on nitrogen were designed and synthesized. Bioassay results showed that all the synthetic compounds exhibited lower antifungal activi
- Wu, Zhibing,Yang, Guangqian,Zhao, Xin,Wu, Jiangchun,Wu, Shixi
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Read Online
- Synthesis, characterization and catalytic activity of saturated and unsaturated N-heterocyclic carbene iridium(I) complexes
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Both saturated and unsaturated N-benzyl substituted heterocyclic carbene (NHC) iridum(i) complexes were synthesized. The unsaturated carbene complex [(un-NHC-Bn)Ir(CO)2Cl] in the cis form was prepared via the carbene transfer from the corresponding silver complex to [Ir(COD)2Cl] 2 followed by ligand substitution with CO, whereas the saturated complex was obtained via the transfer from (sat-NHC-Bn)W(CO)5. The treatment of phosphines with (NHC)Ir(CO)2Cl complexes yielded the products with the phosphine ligand trans to the carbene moiety via substitution. X-Ray structural determination shows that distances of Ir-C(carbene) in both (un-NHC-Bn)Ir(CO)(PR3)Cl and (un-NHC-Bn)Ir(CO)(PR 3)Cl are essentially the same. Analyses of spectroscopic and crystal structural data of iridium complexes [(NHC)Ir(CO)(PR3)Cl] and Vaska's complex show similar corresponding data in both types of complexes, suggesting that the studied NHC ligands and phosphines have similar bonding with Ir(i) metal center. All iridium complexes studied in this work illustrated their catalytically activity on N-alkylation of amine with alcohol via hydrogen transfer reduction. It appears no dramatic difference on the catalytic activity among these iridium carbene complexes; but the saturated carbene complex (sat-NHC-Bn)Ir(CO)(PR3)Cl appears to be slightly more active. For example, the reaction of benzyl alcohol with aniline in the presence of catalyst (1 mol%) under basic conditions at 100 °C provided the secondary amine (N-benzylaniline) in 96% yield.
- Chang, Yung-Hung,Fu, Ching-Feng,Liu, Yi-Hong,Peng, Shei-Ming,Chen, Jwu-Ting,Liu, Shiuh-Tzung
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Read Online
- Biorenewable carbon-supported Ru catalyst for: N -alkylation of amines with alcohols and selective hydrogenation of nitroarenes
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Herein, we developed a renewable carbon-supported Ru catalyst (Ru/PNC-700), which was facilely prepared via simple impregnation followed by the pyrolysis process. The prepared Ru/PNC-700 catalyst demonstrated remarkable catalytic activity in terms of conversion and selectivity towards N-alkylation of anilines with benzyl alcohol and chemoselective hydrogenation of aromatic nitro compounds. In addition, local anesthetic pharmaceutical agents (e.g., butamben and benzocaine), including key drug intermediates, were synthesized in excellent yields under mild conditions and in the presence of water as a green solvent. Moreover, the prepared Ru/PNC-700 catalyst could be easily recovered and reused up to five times without any apparent loss in activity and selectivity.
- Goyal, Vishakha,Narani, Anand,Natte, Kishore,Poddar, Mukesh Kumar,Ray, Anjan,Sarki, Naina,Tripathi, Deependra
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p. 14687 - 14694
(2021/08/23)
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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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- Iridium complexes with ligands of 1,8-Naphthyridine-2-carboxylic acid derivatives-preparation and catalysis
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Complexation of 1,8-naphthyridine(Np)-2-carboxylic derivatives L1-L3 [L1 = Np-2-COOH, L2 = Np-2-CONH2, L3 = Np-2-CONHCH2Py] with [Ir(COD)(μ-OMe)]2 yielded the corresponding complexes [Ir(COD)(Ln)] (1~3, n = 1~3, respectively). The potential tridentate L3 behaves as a bidentate donor in the complex 3. Treatment of L1 with [Ir(COD)Cl]2 under nitrogen atmosphere gave a Ir(III) hydride complex [Ir(COD)(L1)HCl] (4). However, carrying out the reaction in the presence of oxygen rendered a Ir(III) dichloride species [Ir(COD)(L1)Cl2] (5). All these complexes were characterized by spectroscopic analyses and X-ray single crystal determination. Catalytic activity of iridium complexes in amination of amines with alcohols was screened. It appears that iridium amido complexes 2 and 3 show excellent catalytic activity on amination of anilines with alcohols in the presence of Cs2CO3 at 120 °C.
- Hsu, Yen-Pin,Li, Ming,Liu, Shiuh-Tzung,Liu, Yi-Hung,Peng, Shie-Ming
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- Bidentate geometry-constrained iminopyridyl nickel-catalyzed synthesis of amines or imines via borrowing hydrogen or dehydrogenative condensation
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The efficient Ni-catalyzed N-alkylation of various anilines with alcohols via borrowing hydrogen is reported using a bidentate geometry-constrained iminopyridyl nickel complex as the catalyst. Substituted benzylic alcohols and short/long chain aliphatic alcohols could be applied as the alkylation sources to couple with aromatic and heteroaromatic amines to give a diverse set of N-alkylation outcomes in moderate to excellent yields. The nickel catalytic system was also suitable for aliphatic amines, selectively delivering the corresponding imines via an acceptorless dehydrogenative condensation strategy.
- Jiang, Yong,Hu, Miao,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan,Jin, Liqun
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supporting information
(2020/11/27)
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- Solvent-Free N-Alkylation and Dehydrogenative Coupling Catalyzed by a Highly Active Pincer-Nickel Complex
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The synthesis and characterization of a pincer-nickel complex of the type (iPr2NNN)NiCl2(CH3CN) is reported here. We have demonstrated the utility of this pincer-nickel complex (0.02 and 0.002 mol %) for the catalytic N-alkylation of amines using various alcohols. Under solvent-free conditions, while the highest yield (ca. 90%) was obtained for the alkylation of 2-aminopyridine with naphthyl-1-methanol, excellent turnovers (34000 TONs) were observed for the alkylation of 2-aminopyridine with 4-methoxybenzyl alcohol. To demonstrate the synthetic utility of these systems, high-yield reactions (up to 98%) have been probed for representative substrates with a higher loading of the pincer-nickel catalyst (4 mol %). DFT studies indicate that while β-hydride elimination is the RDS for alcohol dehydrogenation, the N-alkylated product can be formed either via hydrogenation with a rate-determining σ-bond metathesis or by alcoholysis that has imine insertion as the RDS. All of the corresponding resting states have been observed by HRMS (ESI) analysis. The labeling experiments are also complementary to DFT studies and show evidence for the involvement of the benzylic C-H bond in the RDS with a kCHH/kCHD value of about 2.5. This method has been applied to accomplish efficient (2000 TONs) dehydrogenative coupling leading to various benzimidazoles.
- Arora, Vinay,Dutta, Moumita,Das, Kanu,Das, Babulal,Srivastava, Hemant Kumar,Srivastava, Hemant Kumar,Kumar, Akshai,Kumar, Akshai
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p. 2162 - 2176
(2020/06/05)
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- Selective Synthesis of Secondary Amines from Nitriles by a User-Friendly Cobalt Catalyst
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Selective hydrogenation/reductive amination of nitriles to secondary amines catalyzed by an inexpensive and user-friendly cobalt complex, (Xantphos)CoCl2, is reported. The use of (Xantphos)CoCl2 and ammonia borane (NH3?BH3) combination affords the selective reduction of nitriles to symmetrical secondary amines, whereas the employment of (Xantphos)CoCl2 and dimethylamine borane (Me2NH?BH3) along with external amines produce unsymmetrical secondary amines and tertiary amines. The general applicability of this methodology is demonstrated by the synthesis of 43 symmetrical and unsymmetrical secondary and tertiary amines bearing diverse functionalities. (Figure presented.).
- Sharma, Dipesh M.,Punji, Benudhar
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supporting information
p. 3930 - 3936
(2019/07/12)
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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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- Preparation of the Ru3(CO)8-pyridine-alcohol cluster and its use for the selective catalytic transformation of primary to secondary amines
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The synthesis of pyridine alcohol based ruthenium carbonyl clusters Ru3(hep)2(CO)8 (1), Ru3(hpp)2(CO)8 (2), and Ru3(bhmp-H)2(CO)8 (3) {hep-H = 2-(2-hydroxyethyl)pyridine, hpp-H = 2-(3-hydroxypropyl)pyridine and bhmp-H2 = 2,6-bis(hydroxymethyl)pyridine} has been carried out by the reaction of the corresponding pyridine-alcohol ligands with Ru3(CO)12. Clusters 1-3 have been characterized using elemental analysis, NMR, FT-IR, mass spectrometry and single-crystal X-ray structures. The clusters were explored for the selective catalytic transformation of primary amines into secondary amines using alcohols as the mono-alkylating agents via hydrogen transfer reactions. All three display efficient catalytic activity with 1 being the most effective.
- Singh, Ajeet,Mobin, Shaikh M.,Mathur, Pradeep
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p. 14033 - 14040
(2018/11/23)
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- Mechanistic investigation of imine formation in ruthenium-catalyzed N-alkylation of amines with alcohols
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Imines are observed frequently in ruthenium-catalyzed N-alkylation of amines with alcohols. Herein, nitrogen–phosphine functionalized carbene ligands were developed and used in ruthenium-catalyzed N-alkylation to explore the mechanism of imine formation. The results showed that strongly electron-donating ligands were beneficial for imine formation and alcohol dehydrogenation to generate acid. In addition, with an increase of electron density of nitrogen atom in substituted amines, the yield of imines in N-alkylation was improved. At the same time, with electron-rich imines as substrates, the transfer hydrogenation of imines became difficult. It is suggested that strongly electron-donating ligands and substrates caused an increase of electron density on the ruthenium center, which resulted in the elimination of hydrogen atoms in active species [LRuH2] as hydrogen gas rather than transfer onto the imine coordinated with the ruthenium center.
- Yu, Xiaojun,Li, Yaqiu,Fu, Haiyan,Zheng, Xueli,Chen, Hua,Li, Ruixiang
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- Hemilabile N-heterocyclic carbene (NHC)-nitrogen-phosphine mediated Ru (II)-catalyzed N-alkylation of aromatic amine with alcohol efficiently
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Based on the hemilability, a novel N-heterocyclic carbene (NHC)-nitrogen-phosphine ligand (1) was synthesized, and the combination of it with [Ru(COD)Cl2]n showed the high activity and selectivity with a low Ru loading of 0.1% for the N-alkylation of amine with alcohol. Especially, for these substrates with pyridine backbone, even if the catalyst loading was as low as 0.01%, good yields (81–95%) of the desired products were achieved.
- Yu, Xiao-Jun,He, Hai-Yu,Yang, Lei,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
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- Cyclometalated palladium pre-catalyst for N-alkylation of amines using alcohols and regioselective alkylation of sulfanilamide using aryl alcohols
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Simple pyrazole based palladacycle-phosphine with a high turnover has been developed and applied for the N-alkylation of amines and sulfanilamide using alcohols as substrates by hydrogen borrowing strategy. N-alkylation of primary and secondary amines resulted in high isolated yields at 100–130 °C, under solvent free conditions. More challenging secondary aliphatic as well as aromatic alcohols were also successfully utilized as alkylating agents under similar reaction conditions. The turn over number reached up to 43000 for N-benzylation of aniline using benzyl alcohol. Notably, regioselective N-alkylation of 2-aminobenzothiazole and 4-aminobenzenesulfonamide to the corresponding 2-N-(alkylamino)azoles and 4-amino-(N-alkyl)benzenesulfonamides using alcohols as alkylating agents have been achieved using our new pre-catalyst-phosphine system.
- Mamidala, Ramesh,Mukundam, Vanga,Dhanunjayarao, Kunchala,Venkatasubbaiah, Krishnan
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supporting information
p. 2225 - 2233
(2017/03/24)
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- Efficient and practical catalyst-free-like dehydrative N-alkylation of amines and sulfinamides with alcohols initiated by aerobic oxidation of alcohols under air
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We developed simple and practical N-alkylation reactions of amines and sulfinamides with primary and secondary alcohols by using only catalytic amounts of air as the initiator without adding any external catalysts. This method has advantages of simple conditions, easy operation, and comparatively wider scope of substrates, providing an efficient and green catalyst-free-like alcohol-based dehydrative N-alkylation method. Mechanistic studies revealed that air initiated the reactions by aerobic oxidation of the alcohols to the key initiating aldehydes or ketones in the presence of bases.
- Li, Xiaohui,Li, Shuangyan,Li, Qiang,Dong, Xu,Li, Yang,Yu, Xiaochun,Xu, Qing
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supporting information
p. 264 - 272
(2015/12/30)
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- Lewis acid activation of pyridines for nucleophilic aromatic substitution and conjugate addition
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A clean, mild and sustainable method for the functionalization of pyridines and their analogues is reported. A zinc-based Lewis acid is used to activate pyridine and its analogues towards nucleophilic aromatic substitution, conjugate addition, and cyclization reactions by binding to the nitrogen on the pyridine ring and activating the pyridine ring core towards further functionalization.
- Abou-Shehada, Sarah,Teasdale, Matthew C.,Bull, Steven D.,Wade, Charles E.,Williams, Jonathan M. J.
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p. 1083 - 1087
(2015/03/30)
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- Green and scalable aldehyde-catalyzed transition metal-free dehydrative N-alkylation of amides and amines with alcohols
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In contrast to the borrowing hydrogen-type N-alkylation reactions, in which alcohols were activated by transition metal-catalyzed anaerobic dehydrogenation, the addition of external aldehydes was accidentally found to be a simple and effective protocol for alcohol activation. This interesting finding subsequently led to an efficient and green, practical and scalable aldehyde-catalyzed transition metal-free dehydrative N-alkylation method for a variety of amides, amines, and alcohols. Mechanistic studies revealed that this reaction most possibly proceeds via a simple but interesting transition metal-free relay race mechanism. Copyright
- Xu, Qing,Li, Qiang,Zhu, Xiaogang,Chen, Jianhui
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supporting information
p. 73 - 80
(2013/03/13)
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- A bis(phosphaethenyl)pyridine complex of iridium(I): Synthesis and catalytic application to N-alkylation of amines with alcohols
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The iridium(I) complex [IrCl(BPEP-H)] (1), coordinated with 2,6-bis[2-(2,4,6-tri-tert-butylphenyl)-2-phosphaethenyl]pyridine (BPEP-H) as a PNP-pincer-type phosphaalkene ligand, has been synthesized and fully characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction analysis. Complex 1 (1 mol %) catalyzes N-alkylation of primary and secondary amines with alcohols, leading to the selective formation of secondary and tertiary amines, respectively. Primary amines are smoothly alkylated with a variety of benzylic and aliphatic alcohols (1 or 3 equiv) at 100 C under basic conditions (CsOH, 10 mol %) to give the corresponding secondary amines in good to high yields. On the other hand, N-alkylation of secondary amines with benzyl alcohol (3 equiv) proceeds in the presence of KH2PO4 (5 mol %) at 140 C to afford tertiary amines in high yields.
- Chang, Yung-Hung,Nakajima, Yumiko,Ozawa, Fumiyuki
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p. 2210 - 2215
(2013/05/21)
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- Palladium-catalyzed N-alkylation of amides and amines with alcohols employing the aerobic relay race methodology
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Possibly because homogeneous palladium catalysts are not typical borrowing hydrogen catalysts and ligands are thus ineffective in catalyst activation under conventional anaerobic conditions, they had not been used in the N-alkylation reactions of amines/amides with alcohols in the past. By employing the aerobic relay race methodology with Pd-catalyzed aerobic alcohol oxidation being a more effective protocol for alcohol activation, ligand-free homogeneous palladiums are successfully used as active catalysts in the dehydrative N-alkylation reactions, giving high yields and selectivities of the alkylated amides and amines. Mechanistic studies implied that the reaction most probably proceeds via the novel relay race mechanism we recently discovered and proposed. By employing the aerobic relay race methodology with Pd-catalyzed aerobic alcohol oxidation being a more effective protocol for alcohol activation, ligand-free homogeneous palladiums are successfully used as active catalysts in the dehydrative N-alkylation reactions of amines and amides with alcohols, giving high yields and selectivities of the alkylated amines and amides. Mechanistic studies implied that the reaction most probably proceeds via the novel relay race mechanism we recently discovered and proposed. Copyright
- Yu, Xiaochun,Jiang, Lan,Li, Qiang,Xu, Qing,Xie, Yuanyuan
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p. 2322 - 2332,11
(2020/09/16)
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- N-Alkylation of poor nucleophilic amines and derivatives with alcohols by a hydrogen autotransfer process catalyzed by copper(II) acetate: Scope and mechanistic considerations
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Copper(II) acetate is a versatile, cheap and simple catalyst for the selective N-monoalkylation of amino derivatives with poor nucleophilic character, such as aromatic and heteroaromatic amines as well as carboxamides, phosphinamides, sulfonamides, and phosphazenes, using in all cases primary alcohols as initial source of the electrophiles, through a hydrogen autotransfer process. In the case of sulfonamides, the monoalkylation process followed by a naphthalene-catalyzed reductive deprotection gives primary amines, which is an indirect alternative to the direct monoalkylation of ammonia. A study of the reaction using deuterium labelled reagents was performed, indicating that the dehydrogenation and hydrogenation steps do not take placed on the same copper-atom coordination sphere, with the condensation step occurring out of the dehydrogenating catalytic species.
- Martínez-Asencio, Ana,Ramón, Diego J.,Yus, Miguel
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experimental part
p. 3140 - 3149
(2011/05/06)
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- Impregnated ruthenium on magnetite as a recyclable catalyst for the N-alkylation of amines, sulfonamides, sulfinamides, and nitroarenes using alcohols as electrophiles by a hydrogen autotransfer process
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Various impregnated metallic salts on magnetite have been prepared, including cobalt, nickel, copper, ruthenium, and palladium salts, as well as a bimetallic palladium - copper derivative. Impregnated ruthenium catalyst is a versatile, inexpensive, and simple system for the selective N-monoalkylation of amino derivatives with poor nucleophilic character, such as aromatic and heteroaromatic amines, sulfonamides, sulfinamides, and nitroarenes, using in all cases alcohols as the initial source of the electrophile, through a hydrogen autotransfer process. In the case of sulfinamides, this is the first time that these amino compounds have been alkylated following this strategy, allowing the use of chiral sulfinamides and secondary alcohols to give the alkylated compound with a diastereomeric ratio of 92:8. In these cases, after alkylation, a simple acid deprotection gave the expected primary amines in good yields. The ruthenium catalyst is quite sensitive, and small modifications of the reaction medium can change the final product. The alkylation o amines using potassium hydroxide renders the N-monoalkylated amines, and the same protocol using sodium hydroxide yields the related imines. The catalyst can be easily removed by a simple magnet and can be reused up to ten times, showing the same activity.
- Cano, Rafael,Ramon, Diego J.,Yus, Miguel
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experimental part
p. 5547 - 5557
(2011/08/10)
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- Palladium(II) acetate as catalyst for the N-alkylation of aromatic amines, sulfonamides, and related nitrogenated compounds with alcohols by a hydrogen autotransfer process
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Palladium(II) acetate is a versatile, inexpensive, and simple catalyst for the selective N-monoalkylation of amino derivatives with poor nucleophilic character, such as aromatic and heteroaromatic amines as well as carboxamides, sulfonamides, and phosphazenes, using, in all cases, primary alcohols as the initial source of the electrophile, through a hydrogen autotransfer process. The regioselectivity of the benzothiazol-2-amine alkylation is contrary to that found using halogenated electrophiles.
- Martinez-Asencio, Ana,Yus, Miguel,Ramon, Diego J.
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experimental part
p. 3730 - 3740
(2011/12/21)
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- Coordination and catalytic activity of ruthenium complexes containing tridentate P,N,O ligands
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The coordination chemistry of RuII ions with [2-(diphenylphosphanyl)-N-(o-hydroxybenzylidene)]aniline (PNO-H) and the methylated analogue PNO-Me have been studied. Thus, [(PNO)RuCl(dmso) 2] (1), [(PNO)2Ru] (2), [(PNO)RuCl(PPh3)] (3) and [(PNO)RuCl(CO)2] (4) were synthesized by reactions of various RuII precursors with PNO-H. Treatment of PNO-Me with [RuCl 2(dmso)4] resulted in in the formation of [P,N-(PNO-Me)Ru(dmso)2Cl2] (5). However, complexation of PNO-Me with [RuCl2(CO)3(THF)] (THF = tetrahydrofuran) provided a mixture of [P,N-(PNO-Me)Ru(CO)2Cl2] (6) and 4 because O-demethylation took place during the reaction. All of the Ru II complexes have been characterized by elemental analysis and spectroscopic techniques, as well as X-ray crystal structural analysis for 2, 4 and 6. The ruthenium complexes investigated in this work, except 2, are good precatalysts for the reductive amination of amine with alcohols, and 4 appears to be the best. Moreover, 4 can catalyze the direct amination of nitrobenzene with benzyl alcohol to the corresponding secondary amine. Ruthenium complexes containing P,N,O ligands have been synthesized and characterized. These Ru II species appear to be good catalysts for the reductive amination of amines or nitrobenzene with alcohols.
- Lee, Chun-Chin,Chu, Wan-Yi,Liu, Yi-Hong,Peng, Shie-Ming,Liu, Shiuh-Tzung
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experimental part
p. 4801 - 4806
(2011/12/05)
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- Highly active and selective supported iron oxide nanoparticles in microwave-assisted N-alkylations of amines with alcohols
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Highly active and stable supported iron oxide nanoparticles show excellent activities and switchable selectivities to target products in the microwave-assisted N-alkylation of amines with alcohols. The Royal Society of Chemistry 2010.
- Gonzalez-Arellano, Camino,Yoshida, Kenta,Luque, Rafael,Gai, Pratibha L.
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experimental part
p. 1281 - 1287
(2010/10/04)
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- Ligand-free copper-catalyzed amination of heteroaryl halides with alkyl- and arylamines
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N-Heteroarylations of alkyl- and arylamines with various heteroaryl halides have been achieved by ligand-free copper-catalyzed cross-couplings affording aminopyridines and aminopyrimidines in moderate to high yields (up to 99% yield). Copyright
- Liu, Zhen-Jiang,Vors, Jean-Pierre,Gesing, Ernst R. F.,Bolm, Carsten
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supporting information; scheme or table
p. 3158 - 3162
(2011/02/26)
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- N-Alkylation of poor nucleophilic amine and sulfonamide derivatives with alcohols by a hydrogen autotransfer process catalyzed by copper(II) acetate
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Copper(II) acetate is a versatile, cheap, and simple catalyst for the selective N-monoalkylation of amino derivatives with poor nucleophilic character, such as aromatic and heteroaromatic amines as well as sulfonamides, using in all cases primary alcohols as initial source of the electrophiles, through a hydrogen autotransfer process. In the case of sulfonamides, the monoalkylation process followed by a naphthalene-catalyzed reductive deprotection gives primary amines, which is an indirect alternative to the direct monoalkylation of ammonia.
- Martínez-Asencio, Ana,Ramón, Diego J.,Yus, Miguel
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scheme or table
p. 325 - 327
(2010/03/04)
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- Polymethylhydrosiloxane (PMHS)/trifluoroacetic acid (TFA): a novel system for reductive amination reactions
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Polymethylhydrosiloxane (PMHS)/trifluoroacetic acid (TFA) was discovered as a novel metal-free system for reductive amination reactions. A variety of (het)aryl amines as well as a representative carbamate and urea were successfully alkylated by benzaldehyde in the presence of PMHS and TFA in dichloromethane at room temperature in moderate to excellent yields (28-87%). Furthermore, this reaction protocol was successfully applied to the alkylation of p-nitroaniline with a wide range of aldehydes, ketones, and a representative acetal to obtain the alkylated products in yields ranging from 40% to 92%. The current work represents one of the very few examples of PMHS being activated by a Br?nsted acid.
- Patel, Jay P.,Li, An-Hu,Dong, Hanqing,Korlipara, Vijaya L.,Mulvihill, Mark J.
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scheme or table
p. 5975 - 5977
(2010/01/18)
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- Selective N-monoalkylation of aromatic amines with benzylic alcohols by a hydrogen autotransfer process catalyzed by unmodified magnetite
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A new catalyst for an old material: magnetite is a good catalyst for the selective N-alkylation of aromatic amines using benzylic alcohols as electrophiles. The process could be repeated up to eight times without losing effectiveness. The catalyst recycling is very easy, using a simple magnet. The catalyst is selective and could discriminate between aromatic and aliphatic amines, as well as between benzylic and aliphatic alcohols, as the reactions only take place with aromatic amines and benzylic alcohols.
- Martinez, Ricardo,Ramon, Diego J.,Yus, Miguel
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experimental part
p. 2176 - 2181
(2009/09/04)
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- Quinazolines as MMP-13 inhibitors
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A compound selected from those of formula (I): in which: R1 represents a group selected from hydrogen, amino, alkyl, alkenyl, aminoalkyl, aryl, arylalkyl, heterocycle, and cycloalkylalkyl, optionally substituted, W represents oxygen, sulfhur, or ═N—R′, in which R′ is as defined in the description, X1, X2 and X3 represent nitrogen or —C—R6 in which R6 is as defined in the description, Y represents oxygen, sulfhur, —NH, or —N(C1-C6)alkyl, Z represents oxygen, sulfhur, —NR7 in which R7 is as defined in the description, and 59 optionally carbon atom, n is an integer from 1 to 8 inclusive, Z1 represents —CR8R9 wherein R8 and R9 are as defined in the description, A represents aromatic or non-aromatic, heterocyclic or non-heterocyclic ring system, m is an integer from 0 to 7 inclusive, the group(s) R2 is (are) is as defined in the description, R3 represents hydrogen, alkyl, alkenyl, alkynyl, ot a group of formula: in which Z2, B, R5, P and q are as defined in the description, optionally, the racemic forms thereof, isomers thereof, N-oxydes thereof, and the pharmaceutically acceptable salts thereof, and medicinal products containing the same are useful as specific inhibitors of type-13 matrix metalloprotease.
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- Simple, efficient catalyst system for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates
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Palladium complexes supported by (o-biphenyl)P(t-Bu)2 (3) or (o- biphenyl)PCy2 (4) are efficient catalysts for the catalytic amination of a wide variety of aryl halides and triflates. Use of ligand 3 allows for the room-temperature catalytic amination of many aryl chloride, bromide, and triflate substrates, while ligand 4 is effective for the amination of functionalized substrates or reactions of acyclic secondary amines. The catalysts perform well for a large number of different substrate combinations at 80-110 °C, including chloropyridines and functionalized aryl halides and triflates using 0.5-1.0 mol % Pd; some reactions proceed efficiently at low catalyst levels (0.05 mol % Pd). These ligands are effective for almost all substrate combinations that have been previously reported with various other ligands, and they represent the most generally effective catalyst system reported to date. Ligands 3 and 4 are air-stable, crystalline solids that are commercially available. Their effectiveness is believed to be due to a combination of steric and electronic properties that promote oxidative addition, Pd-N bond formation, and reductive elimination.
- Wolfe, John P.,Tomori, Hiroshi,Sadighi, Joseph P.,Yin, Jingjun,Buchwald, Stephen L.
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p. 1158 - 1174
(2007/10/03)
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- Amination, III. Trimethylsilanol as Leaving Group, V. Silylation - Amination of Hydroxy N-Heterocycles
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Hydroxy N-heterocycles such as 18, 21, 26, and others are efficiently aminated in a one-step/one-pot procedure by silylation-amination to give 20, 23 - 25 etc.Silylation converts aromatic hydroxy N-heterocycles into activated and lipophilic intermediates of type 3, 8 which react in situ with ammonia, primary or secondary amines to form the corresponding mono-, bis- or tris-aminated products (5, 10).This addition-elimination of amines to O-silylated heterocycles is Lewis acid-catalysed and proceeds usually in high yields if the leaving group trimethylsilanol is converted in situ by excess silylated agent into hexamethyldisiloxane.Scope and limitations of this simple procedure are discussed.
- Vorbrueggen, Helmut,Krolikiewicz, Konrad
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p. 1523 - 1541
(2007/10/02)
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- Process for the preparation of amino derivatives of N-heterocycles
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A process for the preparation amino derivatives of N-heterocycles comprises reacting a hydroxy-N-heterocycle with hexamethylcyclotrisilazane (HTS) and/or octamethylcyclotetrasilazane (OTS) and then with NH3, or a primary or secondary amine, esp
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