- Reusable Co-nanoparticles for general and selectiveN-alkylation of amines and ammonia with alcohols
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A general cobalt-catalyzedN-alkylation of amines with alcohols by borrowing hydrogen methodology to prepare different kinds of amines is reported. The optimal catalyst for this transformation is prepared by pyrolysis of a specific templated material, which is generatedin situby mixing cobalt salts, nitrogen ligands and colloidal silica, and subsequent removal of silica. Applying this novel Co-nanoparticle-based material, >100 primary, secondary, and tertiary amines includingN-methylamines and selected drug molecules were conveniently prepared starting from inexpensive and easily accessible alcohols and amines or ammonia.
- Beller, Matthias,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kadam, Ravishankar G.,Li, Xinmin,Ma, Zhuang,Petr, Martin,Zbo?il, Radek,Zhou, Bei
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p. 111 - 117
(2022/01/06)
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- Effect of the ancillary ligand in N-heterocyclic carbene iridium(III) catalyzed N-alkylation of amines with alcohols
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A series of air-stable N-heterocyclic carbene (NHC) Ir(III) complexes (Ir1-6), bearing various combinations of chlorine, pyridine and NHC ligands, were assayed for the N-alkylation of amines with alcohols. It was found that Ir3, with two monodentate 1,3-bis-methyl-imidazolylidene (IMe) ligands, emerged as the most active complex. A large variety of amines and primary alcohols were efficiently converted into mono-N-alkylated amines in 53–96% yields. As a special highlight, for the challenging MeOH, selective N-monomethylation could be achieved using KOH as a base under an air atmosphere. Moreover, this catalytic system was successfully applied to the gram-scale synthesis of some valuable compounds.
- Feng, Xinshu,Huang, Ming
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- Ru-Catalyzed Selective Catalytic Methylation and Methylenation Reaction Employing Methanol as the C1 Source
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Methanol can be employed as a green and sustainable methylating agent to form C-C and C-N bonds via borrowing hydrogen (BH) methodology. Herein we explored the activity of the acridine-derived SNS-Ru pincer for the activation of methanol to apply it as a C1 building block in different reactions. Our catalytic system shows great success toward the β-C(sp3)-methylation reaction of 2-phenylethanols to provide good to excellent yields of the methylated products. We investigated the mechanistic details, kinetic progress, and temperature-dependent product distribution, which revealed the slow and steady generation of in situ formed aldehyde, is the key factor to get the higher yield of the β-methylated product. To establish the environmental benefit of this reaction, green chemistry metrics are calculated. Furthermore, dimerization of 2-naphthol via methylene linkage and formation of N-methylation of amine are also described in this study, which offers a wide range of substrate scope with a good to excellent yield.
- Biswas, Nandita,Srimani, Dipankar
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p. 10544 - 10554
(2021/07/31)
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- Simple RuCl3-catalyzed N-Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol
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Methanol is a potential hydrogen source and C1 synthon, which finds interesting applications in both chemical synthesis and energy technologies. The effective utilization of this simple alcohol in organic synthesis is of central importance and attracts scientific interest. Herein, we report a clean and cost-competitive method with the use of methanol as both C1 synthon and H2 source for selective N-methylation of amines by employing relatively cheap RuCl3.xH2O as a ligand-free catalyst. This readily available catalyst tolerates various amines comprising electron-deficient and electron-donating groups and allows them to transform into corresponding N-methylated products in moderate to excellent yields. In addition, few marketed pharmaceutical agents (e. g., venlafaxine and imipramine) were also successfully synthesized via late-stage functionalization from readily available feedstock chemicals, highlighting synthetic value of this advanced N-methylation reaction. Using this platform, we also attempted tandem reactions with selected nitroarenes to convert them into corresponding N-methylated amines using MeOH under H2-free conditions including transfer hydrogenation of nitroarenes-to-anilines and prepared drug molecules (e. g., benzocaine and butamben) as well as key pharmaceutical intermediates. We further enable one-shot selective and green syntheses of 1-methylbenzimidazole using ortho-phenylenediamine (OPDA) and methanol as coupling partners.
- Sarki, Naina,Goyal, Vishakha,Tyagi, Nitin Kumar,Puttaswamy,Narani, Anand,Ray, Anjan,Natte, Kishore
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p. 1722 - 1729
(2021/04/19)
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- P(III)/P(V)-Catalyzed Methylamination of Arylboronic Acids and Esters: Reductive C-N Coupling with Nitromethane as a Methylamine Surrogate
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The direct reductive N-arylation of nitromethane by organophosphorus-catalyzed reductive C-N coupling with arylboronic acid derivatives is reported. This method operates by the action of a small ring organophosphorus-based catalyst (1,2,2,3,4,4-hexamethylphosphetane P-oxide) together with a mild terminal reductant hydrosilane to drive the selective installation of the methylamino group to (hetero)aromatic boronic acids and esters. This method also provides for a unified synthetic approach to isotopically labeled N-methylanilines from various stable isotopologues of nitromethane (i.e., CD3NO2, CH315NO2, and 13CH3NO2), revealing this easy-to-handle compound as a versatile precursor for the direct installation of the methylamino group.
- Li, Gen,Qin, Ziyang,Radosevich, Alexander T.
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supporting information
p. 16205 - 16210
(2020/10/26)
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- Selective N -monomethylation of primary anilines with the controllable installation of N -CH2D, N -CHD2, and N -CD3units
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The selective N-monomethylation of primary anilines was realized by the use of the Me3N-BH3/N,N-dimethylformamide (DMF) system as the methyl source. This method also allows for the controllable introduction of N-CH2D, N-CHD2, and N-CD3 units with high lev
- Meng, Jing,Wang, Yi-Feng,Wang, Zhijuan,Xia, Hui-Min,Xu, Ai-Qing,Zhang, Feng-Lian
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supporting information
p. 4922 - 4926
(2020/07/30)
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- Asymmetric construction of quaternary α-nitro amides by palladium-catalyzed C(sp3)-H arylation
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Pd-Catalyzed enantioselective C(sp3)-H arylation of N-(o-Br-aryl) anilides has been disclosed, and quaternary α-nitro amides were constructed with up to 98% ee. The presence of the nitro group on the substrate enables the progress of the reaction and the ready transformation of the product to optically active quaternary amino acid derivatives.
- Kong, Wei-Xin,Xie, Shi-Jing,Cao, Chen-Yao-Zi,Zhang, Chao-Wei,Wang, Chuanyong,Duan, Wei-Liang
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supporting information
p. 2292 - 2295
(2020/03/04)
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- Bimetallic Bis-NHC-Ir(III) Complex Bearing 2-Arylbenzo[d]oxazolyl Ligand: Synthesis, Catalysis, and Bimetallic Effects
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Herein, an unprecedented bimetallic bis-NHC Cp*Ir complex 1 bearing 2-arylbenzo[d]oxazolyl and NHC ligands is reported. A significant increase in activity was observed for N-methylation of amines and reduction of aldehydes with MeOH catalyzed by 1 compared to the monometallic analogues (2-11). Under the optimal conditions, it showed to be highly effective in N-methylation of nitroarenes with MeOH as both C1 and H2 source. Substrates, including aromatic amines, ketones, and nitro compounds with various functional groups, can be well-tolerated. Mechanistic studies and DFT calculation highlight the significance of bimetallic centers cooperativity.
- Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhan, Bing,Li, Zhi-Ming,Hou, Xiu-Feng
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p. 3514 - 3523
(2020/10/09)
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- Preparation method for arylvinylsilane compound
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The invention relates to the technical field of chemical synthesis and discloses a preparation method for an arylvinylsilane compound. The preparation method comprises the following steps: adding a raw material A, a raw material B, a catalytic precursor and an oxidant into a reaction medium, and conducting reacting at 25-80 DEG C for 1-24 h; and then conducting separating to obtain the arylvinylsilane compound, wherein the raw material A is an aromatic hydrocarbon compound containing a heteroatom orienting group, the raw material B is vinylsilane and the catalytic precursor is a palladium salt. According to the preparation method, the vinylsilane and the aromatic hydrocarbon compound containing the heteroatom orienting group are used as the raw materials, the palladium salt is used as thecatalytic precursor and the oxidants including silver acetate and the like are added; then the components are subjected to a one-step reaction in an organic solvent to synthesize a target product. Themethod provided by the invention has the advantages of relatively good adaptability to substrates containing substituent groups having different properties, high yield, good stereoselectivity, no need of ligands, no need of protection of inert gas and simplicity in operation.
- -
-
Paragraph 0018; 0032; 0037; 0042; 0050; 0055; 0060; 0065
(2020/02/14)
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- Substituent Effect Induces Emission Modulation of Stilbene Photoswitches by Spatial Tuning of the N/B Electronic Constraints
-
We present a family of stilbene derivatives (1-4) ortho-functionalized with an electron donor and acceptor. Their emission was tuned by donor substitutions, dictating charge transfer dependent on the N···B spatial separation. The steric reduction of subst
- Chen, Pangkuan,Ji, Guangqian,Wang, Nan,Yin, Xiaodong
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supporting information
(2020/07/30)
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- Preparation method of N-methyl-4-bromoaniline
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The invention provides a preparation method of N-methyl-4-bromoaniline, belonging to the technical field of organic synthesis. The preparation method solves the technical problems that existing monomethylation reaction steps of aniline are tedious and the purity of prepared products is low. The method comprises the following steps: 1, adding dichloroethane and N-methylaniline into a first reactor,then dropwise adding acetic anhydride into the first reactor, and carrying out stirring; 2, dropwise adding a brominating agent into the formed reaction system, carrying out stirring, carrying out sampling analysis until the content of N-methyl acetanilide is less than 1%, adding sodium sulfite, carrying out stirring, and carrying out suction filtration; 3, adding the solid N-methyl-4-bromoacetanilide obtained through suction filtration in the step 2 into a second reactor, then adding hydrochloric acid with a mass concentration of 15%, carrying out heating reflux for 3 h, and carrying out sampling analysis until a reaction is completed; and 4, cooling, neutralizing and extracting the reaction system in the step 3, and recovering the solvent to obtain the colorless transparent liquid N-methyl-4-bromoaniline. The N-methyl-4-bromoaniline prepared by using the method is high in purity, and has a content of greater than 98%.
- -
-
Paragraph 0066-0068
(2019/12/25)
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- Manufacturing method for halogen substituted N-methylaniline
-
The present invention relates to a method for manufacturing halogen-substituted N-methylaniline from halogen-substituted aniline. When halogen-substituted N-methylaniline is manufactured by using the method of the present invention, it is possible to manufacture halogen-substituted N-methylaniline without using existing methoxide sodium which has low chemical stability and is expensive, by using a low-cost base having excellent chemical stability such as potassium hydroxide or sodium hydroxide. Therefore, it is possible to reduce costs in a manufacturing process and to produce N-methylaniline with a high yield and high purity, thereby being useful for mass production as a raw material for herbicide metamifop synthesis.COPYRIGHT KIPO 2019
- -
-
Paragraph 0025-0030; 0035; 0036; 0043
(2019/09/05)
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- N -Methylation of ortho -substituted aromatic amines with methanol catalyzed by 2-arylbenzo [d] oxazole NHC-Ir(iii) complexes
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Seven new chelated cyclometalated Ir complexes of ABON,P, ABON,O, and ABON,C(carbene) based on a rigid and tunable 2-arylbenzo[d]oxazole backbone have been prepared for the N-methylation of amines. Among these three coordinated modes, ABON,C(carbene)-chelated iridium-based catalysts exhibited good performance in the monomethylation of aromatic amines with methanol (MeOH) as the green methylation reagent. The steric-modified synthesis of ABON,C(carbene) complexes was described. The most active ABON,C(carbene) complex with marginal steric hindrance as a catalyst was obtained from the benzoxazole ring without a substituent and methyl group of the benzimidazole ring on the N-heterocyclic carbene (NHC) ligand. A variety of amines including para- and meta-substituted aromatic amines, as well as heterocyclic amines, were formulated as suitable substrates. Importantly, this catalyst considerably promoted the yield of the N-methylation of ortho-substituted aromatic amines. Controlled kinetic experiments and deuterium-labeling reactions of these ortho-substituted amines were conducted under optimized conditions. On the basis of the experimental results, a plausible mechanism was proposed.
- Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhou, Quan,Lin, Yue-Jian,Hou, Xiu-Feng
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supporting information
p. 5072 - 5082
(2019/04/17)
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- The design, synthesis and evaluation of selenium-containing 4-anilinoquinazoline hybrids as anticancer agents and a study of their mechanism
-
Inhibition of tubulin polymerization is one of the significant strategies in the treatment of cancer. Inspired by the excellent antitumor activity of EP128495 and the beneficial biological activities of selenium compounds, a series of new selenium-containing 4-anilinoquinazoline hybrids were synthesized and evaluated as tubulin polymerization inhibitors. An anti-proliferative activity assay showed that most of the compounds inhibited human sensitive cancer cells at low nanomolar concentrations. A mechanism study revealed that the optimal compound 5a disrupted microtubule dynamics, decreased the mitochondrial membrane potential and arrested HeLa cells in the G2/M phase, finally resulting in cellular apoptosis.
- An, Baijiao,Zhang, Shun,Hu, Jinhui,Pan, Tingting,Huang, Ling,Tang, Johnny Cheuk-On,Li, Xingshu,Chan, Albert S. C.
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p. 4701 - 4714
(2018/07/03)
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- Cp?Rh(iii) catalyzed: Ortho -halogenation of N -nitrosoanilines by solvent-controlled regioselective C-H functionalization
-
We present a novel, efficient, and regioselective method for the rhodium-catalyzed direct C-H ortho-halogenation of anilines that involves a removable N-nitroso directing group. This method featured mild reaction conditions, wide substrate scope, good functional group tolerance and satisfactory yields. To maintain the high ortho-regioselectivity and conversion, increasing the steric hindrance of the solvent was critical. Preliminary mechanistic studies suggest that C-H activation may be involved in the rate-determining step.
- Peng, Qiujun,Hu, Jian,Huo, Jiyou,Yuan, Hongshun,Xu, Lanting,Pan, Xianhua
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supporting information
p. 4471 - 4481
(2018/06/29)
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- Methylation of Amines and Ketones with Methanol Catalyzed by an Iridium Complex Bearing a 2-Hydroxypyridylmethylene Fragment
-
Reaction of complex [Cp?Ir(HOC5H3CH2C5H3OH)Cl][Cl] (1) with AgOTf generated the product [Cp?Ir(HOC5H3CH2C5H3OH)(H2O)][OTf]2 (2), which was further transformed to the complex [Cp?Ir(OC5H3CH2C5H3O)(H2O)] (3) in the presence of t-BuONa via -OH deprotonation. Complexes 1-3 exhibited high activity for the methylation of amines and ketones. These C-C and C-N coupling reactions proceeded in air with 1 mol % catalyst loading in the presence of K2CO3.
- Deng, Danfeng,Hu, Bowen,Yang, Min,Chen, Dafa
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p. 3353 - 3359
(2018/09/25)
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- Expedient Access to 2-Benzazepines by Palladium-Catalyzed C?H Activation: Identification of a Unique Hsp90 Inhibitor Scaffold
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Bioactive 2-benzazepines were accessed in an atom- and step-economical manner through a versatile palladium-catalyzed C?H activation strategy. The C?H arylation required low catalyst loading and a mild base, which was reflected by a broad scope and high functional-group tolerance. The benzotriazolodiazepinones were identified as new heat shock protein 90 (Hsp90) inhibiting lead compounds, with considerable potential for anti-cancer applications.
- Virelli, Matteo,Moroni, Elisabetta,Colombo, Giorgio,Fiengo, Lorenzo,Porta, Alessio,Ackermann, Lutz,Zanoni, Giuseppe
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supporting information
p. 16516 - 16520
(2018/10/25)
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- Palladium(II)/N-Heterocyclic Carbene-Catalyzed Regioselective Heteroannulation of Tertiary Propargyl Alcohols and o-Haloanilines to form 2-Alkenylindoles
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Monometallic and bimetallic palladium(II)/N-heterocyclic carbene complexes appended with naphthalimide or bisnaphthalimide moieties were designed, synthesized, and characterized. Employment of these catalysts brings about the step-economic and regioselective heteroannulation of tertiary propargyl alcohols with o-haloanilines resulting in biologically and pharmaceutically relevant 2-alkenylindoles. Basis for the regioselective heteroannulation is unraveled by coordination of the propargylic hydroxy moiety to palladium during insertion. Embracing this methodology, a single regioisomer of unsymmetrical 2,3-disubstituted indoles could be achieved through late-stage modification. The role of the naphthalimide or bisnaphthalimide appended to the NHC on the catalytic efficiency has been studied. (Figure presented.).
- Panyam, Pradeep Kumar Reddy,Gandhi, Thirumanavelan
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supporting information
p. 1144 - 1151
(2017/04/13)
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- Improved and General Manganese-Catalyzed N-Methylation of Aromatic Amines Using Methanol
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A novel lutidine-based manganese PNP-pincer complex has been synthesized for the selective N-methylation of aromatic amines with methanol. Using borrowing hydrogen methodology, a selection of differently functionalized aniline derivatives is selectively methylated in good yields.
- Neumann, Jacob,Elangovan, Saravanakumar,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
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supporting information
p. 5410 - 5413
(2017/04/27)
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- Intramolecular Pd-catalyzed anomeric C(sp3)-H activation of glycosyl carboxamides
-
An expedient method for the synthesis of fused glycosylquinolin-2-ones and glycosylspirooxindoles through an unprecedented intramolecular Pd-catalyzed anomeric C-H activation of the sugar moiety of 2-bromophenyl glycosylcarboxamides is reported. The scope of the reaction is broad and tolerates a wide range of functional groups.
- Probst, Nicolas,Grelier, Gwendal,Ghermani, NourEddine,Gandon, Vincent,Alami, Mouad,Messaoudi, Samir
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supporting information
p. 5038 - 5041
(2017/11/06)
-
- Iron-catalysed sequential reaction towards α-aminonitriles from secondary amines, primary alcohols and trimethylsilyl cyanide
-
We have developed a one-pot iron-catalysed sequential reaction of secondary amines with primary alcohols, trimethylsilyl cyanide and TBHP under mild reaction conditions to give the corresponding α-aminonitriles.
- Shen, Hang,Hu, Liangzhen,Liu, Qing,Hussain, Muhammad Ijaz,Pan, Jing,Huang, Mingming,Xiong, Yan
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supporting information
p. 2776 - 2779
(2016/02/19)
-
- Palladium-catalyzed α-arylation of enones in the synthesis of 2-alkenylindoles and carbazoles
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A new unified strategy has been developed for the synthesis of substituted 2-alkenylindoles and carbazoles. The strategy uses palladium-catalyzed α-arylation of TES-enol ethers of enones as the key step. The method is highly regioselective, provides good yields, and is expected to have wide application.
- Kale, Ajit Prabhakar,Kumar, Gangam Srikanth,Mangadan, Arun Raj Kizhakkayil,Kapur, Manmohan
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p. 1324 - 1327
(2015/03/14)
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- A High-Throughput Assay for Arylamine Halogenation Based on a Peroxidase-Mediated Quinone-Amine Coupling with Applications in the Screening of Enzymatic Halogenations
-
Arylhalides are important building blocks in many fine chemicals, pharmaceuticals and agrochemicals, and there has been increasing interest in the development of more "green" halogenation methods based on enzyme catalysis. However, the screening and development of new enzymes for biohalogenation has been hampered by a lack of high-throughput screening methods. Described herein is the development of a colorimetric assay for detecting both chemical and enzymatic arylamine halogenation reactions in an aqueous environment. The assay is based on the unique UV/Vis spectrum created by the formation of an ortho-benzoquinone-amine adduct, which is produced by the peroxidase-catalysed benzoquinone generation, followed by Michael addition of either a halogenated or non-halogenated arylamine. This assay is sensitive, rapid and amenable to high-throughput screening platforms. We have also shown this assay to be easily coupled to a flavin-dependent halogenase, which currently lacks any convenient colorimetric assay, in a "one-pot" workflow.
- Hosford, Joseph,Shepherd, Sarah A.,Micklefield, Jason,Wong, Lu Shin
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supporting information
p. 16759 - 16763
(2016/02/12)
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- Syntheses of 2-unsubstituted 1h-1,3-benzazaphospholes from n-formyl-2-bromoanilides
-
The phosphonylation of 2-bromo-formylanilides 1 with triethyl phosphite in the presence of preformed Pd(0)(triethyl phosphite)n catalyst furnished 2-phosphono-formanilides 2 in good yields. Reduction with excess LiAlH4 provided mainl
- Ghalib, Mohammed,Niaz, Basit,Jones, Peter G.,Heinicke, Joachim W.
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p. 452 - 459
(2013/12/04)
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- Thermal switchability of N-chelating hoveyda-type catalyst containing a secondary amine ligand
-
An investigation of aza analogues of the popular Hoveyda-Grubbs catalyst containing a secondary amine ligand is presented, proving the crucial impact of steric as well as electronic factors on the catalyst's stability and performance. The issue of latency in the reactivity profile of studied catalysts is examined, followed by structural and application studies.
- Zukowska, Karolina,Szadkowska, Anna,Pazio, Aleksandra E.,Wo?niak, Krzysztof,Grela, Karol
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experimental part
p. 462 - 469
(2012/04/23)
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- Electronegativity governs enantioselectivity: Alkyl-aryl cross-coupling with fenchol-based palladium-phosphorus halide catalysts
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A series of bulky, modular, monodentate, fenchol-based phosphites has been employed in an intramolecular palladium-catalyzed alkyl-aryl cross-coupling reaction. This enantioselective α-arylation of N-(2-bromophenyl)-N-methyl- 2-phenylpropanamide is accomplished with [Pd(C3H5)(BIFOP- X)(Cl)] as precatalysts, which are based on biphenyl-2,2'-bisfenchol phosphites (BIFOP-X, X=F, Cl, Br, etc.). The phosphorus fluoride BIFOP-F gives the highest enantioselectivity and good yields (64% ee, 88%). Lower selectivities and yields are found for BIFOP halides with heavier halogens (Cl: 74%, 47% ee, Br: 63%, 20% ee). NMR studies on catalyst complexes reveal two equilibrating diastereomeric complexes in equal proportions. In all cases, the phosphorus-halogen moiety remains intact, pointing to its remarkable stability, even in the presence of nucleophiles. The increasing enantioselectivity of the catalysts with the phosphorus halide ligands correlates with the rising electronegativity of the halide (brominechlorinefluorine), as can be rationalized from structural parameters and DFT computations. Copyright
- Trillo, Roberto Blanco,Leven, Matthias,Neudoerfl, Joerg M.,Goldfuss, Bernd
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supporting information; experimental part
p. 1451 - 1465
(2012/08/14)
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- 1,7-palladium migration via C-H activation, followed by intramolecular amination: Regioselective synthesis of benzotriazoles
-
A novel 1,7-palladiummigration-cyclization-dealkylation sequence for the regioselective synthesis of benzotriazoles has been developed. These reactions proceed in excellent yields with high regioselectivities. The mechanism of the reaction has also been investigated.
- Zhou, Jun,He, Jianjun,Wang, Binjie,Yang, Weijun,Ren, Hongjun
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supporting information; experimental part
p. 6868 - 6870
(2011/06/21)
-
- IBiox[(-)-menthyl]: A sterically demanding chiral NHC ligand
-
(Figure Presented) An exceedingly sterically demanding, rigid, and chiral NHC ligand, IBiox[(-)-menthyl] (1), was prepared and structurally characterized. With a buried volume of 50percent, this ligand arguably represents one of the most sterically demanding monodentate ligands. The ability to use aryl chloride substrates in intramolecular palladium-catalyzed ,-arylations reveals its unique reactivity. Moreover, C2-symmetric 1 allows the highly enantioselective formation of oxindoles withup to 99percent ee.
- Wuertz, Sebastian,Lohre, Claudia,Froehlich, Roland,Bergander, Klaus,Glorius, Frank
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supporting information; experimental part
p. 8344 - 8345
(2009/10/24)
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- Synthesis of Cyclopenta[b]indol-1-ones and Carbazol-4-ones from N-(2-Halophenyl)-Substituted Enaminones by Intramolecular Heck Reaction
-
An efficient synthetic route towards N-methylated or nonmethylated 3,4-dihydrocyclopent[b]indol-1(2H)-ones (3) and 1,2,3,9-tetrahydrocarbazol-4(4H)-one (10) was elaborated, based on Pd-catalyzed intramolecular Heck reaction. The chemoselectivity of the cyclization was studied in the case of the bi- and trifunctional substrates 12 and 17, respectively. In the latter case, depending on the catalyst, either the brominated indole 18 or the tetracyclic compound 19 were obtained by single and double Heck reaction, respectively.
- Sorensen, Ulrik S.,Pombo-Villar, Esteban
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-
- Synthesis of functionalized pyrrole and indole derivatives through carbometallation of lithiated double bonds
-
Bis(2-lithioallyl)amines derived from bis(2-bromoallyl)amines undergo intramolecular carbometallation of a lithiated double bond, giving dilithiated dihydropyrroles. The cyclizations are promoted by N,N,N′,N′-tetramethylethylenediamine (TMEDA). Reaction of these intermediates with electrophiles allows the preparation of some new fused and nonfused five-membered functionalized heterocycles. Although 2-lithioallylamines do not suffer intermolecular carbometallation, dimerization products are obtained with their copper or zirconium derivatives. Finally, the application of this new reaction to 2-lithio-N-(2-lithioallyl)anilines leads to 3-lithiomethylindole derivatives, which are transformed to functionalized indole derivatives by reaction with electrophiles.
- Fananas, Francisco J.,Granados, Alejandro,Sanz, Roberto,Ignacio, Jose M.,Barluenga, Jose
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p. 2896 - 2907
(2007/10/03)
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- N-methylanilines from benzylic azides
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Benzylic azides are converted into N-methylanilines efficiently in the presence of a Bronsted or Lewis acid and Et3SiH. The combination of SnCl4/Et3SiH and 4-n-butylbenzyl azide appears to form an aminodiazonium trichlorostannate(II), which undergoes the rearrangement to an iminium salt that is then reduced to N-methyl-4-n-butylaniline by Et3SiH.
- Lopez, Francisco J.,Nitzan, Dov
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p. 2071 - 2074
(2007/10/03)
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- Convergent Routes to the Dioxolophenanthridin-6(5H)-one and 2,3,4,4a-Tetrahydrodioxolophenanthridin-6(5H)-one Nuclei. Application to Syntheses of the Amaryllidaceae Alkaloids Crinasiadine, N-Methylcrinasiadine and Trisphaeridine
-
Convergent routes to the title nuclei, (1) and (6), have been developed.Thus, Suzuki coupling of boronic acid (8) with aryl bromide (9) gave the biarylylcarbamate (7) which, on treatment with phosphorus oxychloride (POCl3), underwent Bischler-Napieralski
- Banwell, Martin G.,Cowden, Cameron J.
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p. 2235 - 2254
(2007/10/02)
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- SURFACTANT CONTROL OF THE ORTHO/PARA RATIO IN THE BROMINATION OF ANILINES
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Products of the bromination reaction of a family of anilines have been examined both in homogeneous solution and in presence of cethyltrimethylammonium bromide (CTAB).The presence of the surfactant induces a high regioselectivity that is opposite to that observed under homogeneous conditions: a high ortho/para ratio has been observed which increases with greater steric hindrance in the ortho position.
- Cerichelli, Giorgio,Luchetti, Luciana,Mancini, Giovanna
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p. 6209 - 6210
(2007/10/02)
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- REGIOSELECTIVE MONOBROMINATION OF AROMATIC AMINES WITH TETRABUTYLAMMONIUM TRIBROMIDE
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A simple and efficient method for monobromination of aromatic amines predominantly in the para position is reported.Tetrabutylammonium tribromide is used at 20 deg C and yields of parabromoanilines are higher than 90percent.
- Berthelot, J.,Guette, C.,Essayegh, M.,Desbene, P.L.,Basselier, J.J.
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p. 1641 - 1646
(2007/10/02)
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