- Iron-Catalysed Direct Aromatic Amination with N-Chloroamines
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An optimized procedure for the direct intra- and intermolecular amination of aromatic C–H bonds with aminium radicals generated from N-chloroamines under iron catalysis is reported. A range of substituted tetrahydroquinolines could be readily prepared, while extension to the synthesis of benzomorpholines was more limited in scope. A direct one-pot variant was developed, allowing direct formal oxidative N–H/C–H coupling.
- Douglas, Gayle E.,Raw, Steven A.,Marsden, Stephen P.
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- Access to gem-Difluoro Olefins via C-H Functionalization and Dual Role of Anilines
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In this Letter, we describe a simple, practical approach in which cheap CuI was used as a catalyst to introduce a gem-difluoro olefin onto simple electron-rich aniline derivatives in good yield via direct C-H functionalization and a subsequent HF elimination reaction. Detailed mechanistic studies point at a dual role of aniline derivatives in this reaction, which serve as a substrate and a basic promoter to trigger the HF elimination step.
- Koenigs, Rene M.,Pei, Chao,Yang, Zhen
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- Reductive: N -methylation of quinolines with paraformaldehyde and H2 for sustainable synthesis of N -methyl tetrahydroquinolines
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A new and straightforward method was developed for the synthesis of N-methyl-1,2,3,4-tetrahydroquinolines by one-pot reductive N-methylation of quinolines with paraformaldehyde and H2 over Pd/C catalyst. A series of functional MTHQs, including (±)-galipinine and (±)-angustrureine were successfully synthesized in good to excellent yields by applying this simple catalyst system.
- Wang, Hongli,Huang, Yongji,Jiang, Qi,Dai, Xingchao,Shi, Feng
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- Novel borane reduction of ether-protected aromatic lactams
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Borane reduction of ether-protected aromatic lactams produces 1-alkyl-1,2,3,4-tetrahydroquinolines (5 and 6) in excellent yields. This reaction provides a novel onepot tandem process for reduction of amide group and N-protected groups. Experimental results demonstrate that the reaction proceeds through two consecutive elimination and reductions via two C-O bond cleavages to form the foresaid products.
- Hu, Wan-Ping,Tsai, Pei-Ching,Hsu, Ming-Kuan,Wang, Jeh-Jeng
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- Investigation of excited state electron-transfer reactions. A search for other associative processes
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The present investigations were carried out to reveal the nature of the photoinduced electron-transfer (ET) process within the electron donors 1,2,3,4-tetrahydroquinoline (THQ) and 1-methyl-1,2,3,4-tetrahydroquinoline (THMe), and widely used acceptor tetracyanoquinodimethane (TCNQ) in the highly polar solvent acetonitrile (ACN) at 300 K.Observations of considerable overlapping between the emisson spectrum of the donor molecules studied in the present in the present investigation and the electronic absorption spectrum of the acceptor TCNQ, coupled to a high negative value of ΔG when one of the chromophores is excited, indicate the possibility of concurrent occurrence of the two processes, e.g. energy and electron transfer.Surprisingly even when the donor chromophore is photoexcited, no spectral manifestation of energy transfer was observed, though both steady state and time resolved (in the time domain of nanosecond order) spectroscopic measurements strongly suggest the occurrence of a highly exothermic ET reaction within the present donor-acceptor systems.Furthermore such ET reactions have been suggested to occur between donor and acceptor separated by a large distance (ca. 7 Angstroem), and quenching of fluorescence emission of donor molecules is caused primarily due to outer sphere ET reactions with the acceptor.Measured electron transfer rates (kET) were found to be of much lower value (ca. 107 s-1).It is demonstrated that loose structure of the transient geminate ion pair complex is formed due to the encounter between excited acceptor (or donor) and unexcited donor (or acceptor), and due to this structural property, a stable anionic species (TCNQ- ion) is produced due to the rapid dissociation (probably in the picosecond time domain) of this excited complex.It is hinted that synthesis of biochromophoric systems in which the present donor and acceptor chromophore would be linked by a polymethylene type (?-type) spacer might be useful in building good photoconducting materials.
- De, R.,Bhattacharyya, S.,Ganguly, T.
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- Photobehavior of mixed π*/ππ* triplets: Simultaneous detection of the two transients, solvent-dependent hydrogen abstraction, and reequilibration upon protein binding
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In the present work, a systematic study on hydrogen abstraction by the excited triplet states of 4-methoxybenzophenone (1) and 4,4′- dimethoxybenzophenone (2) from 1,4-cyclohexadiene (3), 4-methylphenol (4), 1,2,3,4-tetrahydroquinoline (5), and 1-methyl-1,2,3,4-tetrahydroquinoline (6) in different media has been undertaken. Laser flash photolysis (LFP) revealed that in nonpolar solvents, 1 and 2 triplets have a π* configuration with the typical benzophenone-like T-T absorption spectrum (?max ca. 525 nm). Conversely, in aqueous solution, transient absorption spectra with maxima at 450 and 680 nm, attributed to the ππ* triplet, were obtained. Quenching of 1 or 2 triplet by 3 led to ketyl radical formation with rate constants in the range of 106-108 M-1 s -1, being one order of magnitude higher in acetonitrile than in aqueous media. The rate constants of quenching by 4 and 5 were similar in both polar and nonpolar solvents; the highest value was found for 6 in acetonitrile ((6.3 to 6.9) - 109 M-1 s-1). For mechanistic insight, LFP of 1 or 2 in the presence of dimethoxybenzene as electron donor was performed. The results showed that in this case, triplet quenching is favored in aqueous solution. In addition, 2 included in human serum albumin (HSA) was submitted to LFP. The decay kinetics, monitored at 430 nm, fitted well with three lifetimes of 0.45, 1.4, and 14.4 ?s assignable to 2 in bulk solution and in site II or in site I of HSA, respectively. This assignment was confirmed by using oleic acid and ibuprofen as selective displacement probes.
- Jornet, Dolors,Tormos, Rosa,Miranda, Miguel A.
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- CO2-tuned highly selective reduction of formamides to the corresponding methylamines
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We herein describe an efficient, CO2-tuned and highly selective C-O bond cleavage of N-methylated formanilides. With easy-to-handle and commercially available NaBH4 as the reductant, a variety of formanilides could be turned into the desired tertiary amines in moderate to excellent yields. The role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments.
- Chao, Jianbin,Guo, Zhiqiang,Pang, Tengfei,Wei, Xuehong,Xi, Chanjuan,Yan, Leilei
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supporting information
p. 7534 - 7538
(2021/10/12)
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- Metal-free reduction of unsaturated carbonyls, quinones, and pyridinium salts with tetrahydroxydiboron/water
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A series of unsaturated carbonyls, quinones, and pyridinium salts have been effectively reduced to the corresponding saturated carbonyls, dihydroxybenzenes, and hydropyridines in moderate to high yields with tetrahydroxydiboron/water as a mild, convenient, and metal-free reduction system. Deuterium-labeling experiments have revealed this protocol to be an exclusive transfer hydrogenation process from water. This journal is
- Li, Tiejun,Peng, Henian,Tang, Wenjun,Tian, Duanshuai,Xu, Guangqing,Yang, He
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p. 4327 - 4337
(2021/05/31)
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- Heterogeneous Hydrogenation of Quinoline Derivatives Effected by a Granular Cobalt Catalyst
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We communicate a convenient method for the pressure hydrogenation of quinolines in aqueous solution by using a particulate cobalt-based catalyst that is prepared in situ from simple Co(OAc)2 4H2O through reduction with abundant zinc powder. This catalytic protocol permits a brisk and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines thereby relying solely on easy-to-handle reagents that are all readily obtained from commercial sources. Both the reaction setup assembly and the autoclave charging procedure are conducted on the bench outside an inert-gas-operated containment system, thus rendering the overall synthesis time-saving and operationally very simple.
- Timelthaler, Daniel,Topf, Christoph
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- Formic acid disproportionation into formaldehyde triggered by vanadium complexes with iridium catalysis under mild conditions inN-methylation
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Formaldehyde (CH2O) has been used as a key platform reagent in the chemical industry for many decades. Currently, the industrial production of CH2O mainly depends on fossil resources, involving a highly energetic three-step process (200-1100 °C). Herein, we describe renewable formic acid (HCO2H) disproportionation into CH2O triggered by vanadium complexes with iridium catalysis under mild conditions at 30-50 °C inN-methylation. The gram-scale application ofin situgenerated CH2O by HCO2H disproportionation is demonstrated.
- Guo, Yan-Jun,Li, Yang,Zhang, Ping,Zhao, Yu-Rou,Zhou, Chao-Zheng
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supporting information
p. 2918 - 2924
(2021/05/05)
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- Utilization of renewable formic acid from lignocellulosic biomass for the selective hydrogenation and/or N-methylation
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Lignocellulosic biomass is one of the most abundant renewable sources in nature. Herein, we have developed the utilization of renewable formic acid from lignocellulosic biomass as a hydrogen source and a carbon source for the selective hydrogenation and further N-methylation of various quinolines and the derivatives, various indoles under mild conditions in high efficiencies. N-methylation of various anilines is also developed. Mechanistic studies indicate that the hydrogenation occurs via a transfer hydrogenation pathway.
- Zhou, Chao-Zheng,Zhao, Yu-Rou,Tan, Fang-Fang,Guo, Yan-Jun,Li, Yang
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p. 4724 - 4728
(2021/09/06)
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- Bismuth(iii)-catalyzed regioselective alkylation of tetrahydroquinolines and indolines towards the synthesis of bioactive core-biaryl oxindoles and CYP19 inhibitors
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Bismuth(iii)-catalyzed regioselective functionalization at the C-6 position of tetrahydroquinolines and the C-5 position of indolines has been demonstrated. For the first time, one pot symmetrical and unsymmetrical arylation of isatins with tetrahydroquinolines was accomplished giving a completely new product skeleton in good to excellent yields. Most importantly, this protocol leads to the formation of a highly strained quaternary carbon stereogenic center, which is a challenging task. Benzhydryl and 1-phenylethyl trichloroacetimidates have been used as the alkylating partners to functionalize the C-6 and C-5 positions of tetrahydroquinolines and indolines, respectively. The scope of the developed methodology has been extended for the synthesis of the bioactive CYP19-inhibitor and its analogue.
- Prusty, Namrata,Kinthada, Lakshmana K.,Meena, Rohit,Chebolu, Rajesh,Ravikumar, Ponneri Chandrababu
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p. 891 - 905
(2021/02/09)
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- Reductive Alkylation of Quinolines to N-Alkyl Tetrahydroquinolines Catalyzed by Arylboronic Acid
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A boronic acid catalyzed one-pot tandem reduction of quinolines to tetrahydroquinolines followed by reductive alkylation by the aldehyde has been demonstrated. This step-economcial synthesis of N-alkyl tetrahydroquinolines has been achieved directly from readily available quinolines, aldehydes, and Hantzsch ester under mild reaction conditions. The mechanistic study demonstrates the unique behavior of organoboron catalysts as both Lewis acids and hydrogen-bond donors.
- Adhikari, Priyanka,Bhattacharyya, Dipanjan,Nandi, Sekhar,Kancharla, Pavan K.,Das, Animesh
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supporting information
p. 2437 - 2442
(2021/04/05)
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- Borane-Trimethylamine Complex as a Reducing Agent for Selective Methylation and Formylation of Amines with CO2
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We report herein that a borane-trimethylamine complex worked as an efficient reducing agent for the selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline serves as a highly efficient catalyst for the methylation of various secondary amines, whereas in its absence, the formylation of primary and secondary amines was achieved in high yield with high chemoselectivity. Mechanistic studies suggest that the 6-amino-2-picoline-borane catalytic system operates like an intramolecular frustrated Lewis pair to activate CO2.
- Zhang, Yanmeng,Zhang, He,Gao, Ke
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supporting information
p. 8282 - 8286
(2021/10/25)
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- Redox-Selective Iron Catalysis for α-Amino C-H Bond Functionalization via Aerobic Oxidation
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Single-electron oxidation and α-deprotonation of tertiary anilines using Fe(phen)3(PF6)3 afford α-aminoalkyl radicals, which can be coupled with electrophilic partners to afford various tetrahydroquinolines. Mechanistically, the Fe(phen)n 2+/3+ catalytic cycle is maintained by O2 or a TBHP oxidant, and the presence of the oxygen bound iron complex, Fe(III)-OO(H), was elucidated by electron paramagnetic resonance and electrospray ionization mass spectrometry. This redox-selective nonheme iron catalyst behaves similarly to bioinspired heme iron catalysts.
- Hwang, Joon Young,Ji, A. Young,Lee, Sang Hyeok,Kang, Eun Joo
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supporting information
p. 16 - 21
(2019/11/11)
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- Discovery of N-Arylsulfonyl-Indole-2-Carboxamide Derivatives as Potent, Selective, and Orally Bioavailable Fructose-1,6-Bisphosphatase Inhibitors - Design, Synthesis, in Vivo Glucose Lowering Effects, and X-ray Crystal Complex Analysis
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Liver fructose-1,6-bisphosphatase (FBPase) is a key enzyme in the gluconeogenesis pathway. Inhibiting FBPase activity represents a potential treatment for type 2 diabetes mellitus. A series of novel N-arylsulfonyl-4-arylamino-indole-2-carboxamide derivatives have been disclosed as FBPase inhibitors. Through extensive structure-activity relationship investigations, a promising candidate molecule Cpd118 [sodium (7-chloro-4-((3-methoxyphenyl)amino)-1-methyl-1H-indole-2-carbonyl] [(4-methoxyphenyl)sulfonyl)amide] has been identified with high inhibitory activity against human liver FBPase (IC50, 0.029 ± 0.006 μM) and high selectivity relative to the other six AMP-binding enzymes. Importantly, Cpd118 produced significant glucose-lowering effects on both type 2 diabetic KKAy mice and ZDF rats as demonstrated by substantial reductions in the fasting and postprandial blood glucose levels, as well as the HbA1c level. Furthermore, Cpd118 elicited a favorable pharmacokinetic profile with an oral bioavailability of 99.1%. Moreover, the X-ray crystal structure of the Cpd118-FBPase complex was resolved, which revealed a unique binding mode and provided a structural basis for its high potency and selectivity.
- Zhou, Jie,Bie, Jianbo,Wang, Xiaoyu,Liu, Quan,Li, Rongcui,Chen, Hualong,Hu, Jinping,Cao, Hui,Ji, Wenming,Li, Yan,Liu, Shuainan,Shen, Zhufang,Xu, Bailing
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supporting information
p. 10307 - 10329
(2020/11/02)
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- Selective: N-formylation/N-methylation of amines and N-formylation of amides and carbamates with carbon dioxide and hydrosilanes: Promotion of the basic counter anions of the zinc catalyst
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A catalyst composed of commercially available Zn(OAc)2 and 1,10-phenanthroline (phen) was effective in the N-formylation/N-methylation of amines using CO2 as the C1 source in the presence of hydrosilanes. An equimolar reaction of N-methylaniline with PhSiH3 under a CO2 atmosphere yielded the N-formylation product in 92% yield at 25 °C. Scale-up of the reaction using 10 mmol substrate was also successful in affording the desired product in 83% yield (1.1 g). This catalyst exhibits a high thermal stability and a turnover number (TON) of 385000 at 150 °C. In addition, the reaction of N-methylaniline in the presence of excess Ph2SiH2 produced N,N-dimethylaniline. Furthermore, our catalytic protocol was developed for the N-formylation of amides and carbamates, which have smaller pKa values and lower reactivities than the corresponding amines. The present Zn(OAc)2/phen catalyst was found to show versatility in the conversion of CO2 and amines into several functionalized organic chemicals under mild conditions. We propose that the basic counter anion (i.e., the acetate) of the catalyst activates both the Si-H and N-H bonds.
- Zhang, Qiao,Lin, Xiao-Tao,Fukaya, Norihisa,Fujitani, Tadahiro,Sato, Kazuhiko,Choi, Jun-Chul
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supporting information
p. 8414 - 8422
(2020/12/29)
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- Catalyst-free selective: N -formylation and N -methylation of amines using CO2 as a sustainable C1 source
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We herein describe catalyst-free selective N-formylation and N-methylation of amines using CO2 as a sustainable C1 source. By tuning the reaction solvent and temperature, the selective synthesis of formamides and methylamines is achieved in good to excellent yields using sodium borohydride (NaBH4) as a sustainable reductant.
- Zou, Qizhuang,Long, Guangcai,Zhao, Tianxiang,Hu, Xingbang
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supporting information
p. 1134 - 1138
(2020/03/11)
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- Synthesis, Structure, and Properties of Amino-Substituted Benzhydrylium Ions – A Link between Ordinary Carbocations and Neutral Electrophiles
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Optimized synthetic procedures for the straightforward access to eleven amino-substituted diarylmethylium tetrafluoroborates are described. These benzhydrylium ions cover a range of seven orders of magnitude in electrophilicity and provide a link between ordinary carbocations and neutral electrophiles. Five of these highly stabilized benzhydrylium tetrafluoroborates were characterized by single-crystal X-ray crystallography. While the experimentally determined bond lengths and angles in the solid state perfectly agree with those calculated by DFT methods for the gas phase and aqueous solution, crystal packing accounts for large differences in the twist angles of the aryl groups found in the solid state as compared to calculated structures.
- Mayer, Robert J.,Hampel, Nathalie,Mayer, Peter,Ofial, Armin R.,Mayr, Herbert
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supporting information
p. 412 - 421
(2018/09/14)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 3800 - 3806
(2019/07/12)
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- Heterogeneous Catalytic Reduction of Tertiary Amides with Hydrosilanes Using Unsupported Nanoporous Gold Catalyst
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We have demonstrated that the unsupported nanoporous gold (AuNPore) was a green and highly efficient heterogeneous catalyst for the reduction of amides to amines using hydrosilanes as reductants. A variety of tertiary amides with a broad functional groups were reduced to the corresponding tertiary amines in the presence of 2 mol% of AuNPore and PheMe2SiH or (Me2SiH)2O under mild conditions. AuNPore catalyst was recovered by simple filtration and used for twelve times without any loss of catalytic activity. The AuNPore/hydrosilane system was also successfully applied to the hydrosilative reduction of sulfoxides and N-oxides. (Figure presented.).
- Zhao, Yuhui,Zhang, Sheng,Yamamoto, Yoshinori,Bao, Ming,Jin, Tienan,Terada, Masahiro
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supporting information
p. 4817 - 4824
(2019/10/28)
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- Three-Component Aminoselenation of Arynes
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The three-component coupling of tertiary amines, arynes, and aryl selenium bromide or diaryl diselenide as an electrophilic selenium source allowing the synthesis of 2-selanyl aniline derivatives is reported. This aminoselenation reaction of arynes installs a C-N and C-Se bond under mild conditions, and the products are formed in moderate to good yields. This reaction is compatible with various functional groups, and the preliminary studies on the mechanism of the reaction is also provided.
- Gaykar, Rahul N.,Guin, Avishek,Bhattacharjee, Subrata,Biju, Akkattu T.
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supporting information
p. 9613 - 9617
(2019/11/28)
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- Biomass-derived N-doped porous carbon: An efficient metal-free catalyst for methylation of amines with CO2
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Developing green, efficient, and low-cost catalysts for methylation of N-H by using CO2 as the C1 resource is highly desired yet remains a significant challenge. Herein, N-doped porous carbons (NPCs) were designed, synthesized, and proved to be an excellent metal-free catalyst for CO2-participated methylation conversion. NPCs were prepared via the pyrolysis of a mixture of tannic acid and urea. Both theoretical calculation and experiment demonstrate that the N species especially pyridinic N and pyrrolic N within NPCs can work as Lewis basic sites for attacking CO2 to weaken the CO bonds and lower the molecule conversion barrier, facilitating the subsequent methylation of N-H to produce, for example, N,N-dimethylaniline. Besides, the unique porous structure can enrich CO2 and accelerate mass transfer, synergistically promoting the conversion of CO2. The optimized NPC(1/5) catalyst, integrating the porous structure and strong Lewis basicity, exhibits excellent catalytic activity for CO2-based methylation reaction under mild conditions (1 bar CO2, 75 °C). Our work, for the first time, demonstrates the feasibility of using NPCs to catalyze the methylation of amino compounds to produce N,N-dimethylamine by exploiting CO2 as the C1 resource.
- Tang, Feiying,Wang, Liqiang,Liu, You-Nian
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supporting information
p. 6252 - 6257
(2019/12/03)
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- Selective C-H Olefination of Indolines (C5) and Tetrahydroquinolines (C6) by Pd/S,O-Ligand Catalysis
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Herein, we report a highly selective C-H olefination of directing-group-free indolines (C5) and tetrahydroquinolines (C6) by Pd/S,O-ligand catalysis. In the presence of the S,O-ligand, a wide range of challenging indolines, tetrahydroquinolines, and olefins was efficiently olefinated under mild reaction conditions. The synthetic potential of this methodology was demonstrated by the efficient olefination of several indoline-based natural products.
- Jia, Wen-Liang,Westerveld, Nick,Wong, Kit Ming,Morsch, Thomas,Hakkennes, Matthijs,Naksomboon, Kananat,Fernández-Ibá?ez, M. ángeles
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supporting information
p. 9339 - 9342
(2019/11/21)
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- Selective synthesis of formamides, 1,2-bis(N-heterocyclic)ethanes and methylamines from cyclic amines and CO2/H2 catalyzed by an ionic liquid-Pd/C system
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The reduction of CO2 with amines and H2 generally produces N-formylated or N-methylated compounds over different catalysts. Herein, we report the selective synthesis of formamides, 1,2-bis(N-heterocyclic)ethanes, and methylamines, which is achieved over an ionic liquid (IL, e.g., 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIm][BF4])-Pd/C catalytic system. By simply varying the reaction temperature, formamides and methylamines can be selectively produced, respectively, in high yields. Interestingly, 1,2-bis(N-heterocyclic)ethanes can also be obtained via the McMurry reaction of the formed formamide coupled with subsequent hydrogenation. It was found that [BMIm][BF4] can react with formamide to form a [BMIm]+-formamide adduct; thus combined with Pd/C it can catalyze McMurry coupling of formamide in the presence of H2 to afford 1,2-bis(N-heterocyclic)ethane. Moreover, Pd/C-[BMIm][BF4] can further catalyze the hydrogenolysis of 1,2-bis(N-heterocyclic)ethane to access methylamine. [BMIm][BF4]-Pd/C was tolerant to a wide substrate scope, giving the corresponding formamides, 1,2-bis(N-heterocyclic)ethanes or methylamines in moderate to high yields. This work develops a new route to produce N-methylamine and opens the way to produce 1,2-bis(N-heterocyclic)ethane from cyclic amine as well.
- Li, Ruipeng,Zhao, Yanfei,Wang, Huan,Xiang, Junfeng,Wu, Yunyan,Yu, Bo,Han, Buxing,Liu, Zhimin
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p. 9822 - 9828
(2019/11/11)
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- Synthesis of Halogenated Anilines by Treatment of N, N-Dialkylaniline N-Oxides with Thionyl Halides
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The special reactivity of N,N-dialkylaniline N-oxides allows practical and convenient access to electron-rich aryl halides. A complementary pair of reaction protocols allow for the selective para-bromination or ortho-chlorination of N,N-dialkylanilines in up to 69% isolated yield. The generation of a diverse array of halogenated anilines is made possible by a temporary oxidation level increase of N,N-dialkylanilines to the corresponding N,N-dialkylaniline N-oxides and the excision of the resultant weak N-O bond via treatment with thionyl bromide or thionyl chloride at low temperature.
- Reed, Hayley,Paul, Tyler R.,Chain, William J.
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p. 11359 - 11368
(2018/08/06)
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- Iridium-Catalyzed Direct Cyclization of Aromatic Amines with Diols
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We developed an environmentally friendly iridium-catalyzed direct cyclization of aromatic amines with diols that generates the corresponding N-heterocyclic compounds with water as the sole by-product. Thus, under conditions of 165 °C for 18 hours, the direct cyclization of N -methylanilines with 1,3-propanediol by using an IrCl 3 catalyst with rac -BINAP as a ligand in mesitylene afforded the corresponding tetrahydroquinoline derivatives with yields ranging from 73 to 83%. Under similar reaction conditions, direct cyclization of anilines with 1,3-propanediol produced the corresponding tetrahydrobenzoquinolizine derivatives with yields ranging from 26 to 76%.
- Minakawa, Maki,Watanabe, Kouichi,Toyoda, Satoru,Uozumi, Yasuhiro
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supporting information
p. 2385 - 2389
(2018/11/23)
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- Radical-mediated direct C-H amination of arenes with secondary amines
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Aryl dialkyl amines, valuable subunits of a wide range of effect chemicals, are accessed by intramolecular amination of aromatic C-H bonds employing UV photolysis of N-chloroamines. The reactions show good functional group tolerance and allow access to a range of fused and bridged polycyclic structures. The homogeneous reaction conditions allow for the one-pot conversion of secondary amines to their arylated derivatives. Experimental and theoretical evidence supports the involvement of electrophilic aminium radicals which react via direct ortho-attack on the arene.
- Cosgrove, Sebastian C.,Plane, John M. C.,Marsden, Stephen P.
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p. 6647 - 6652
(2018/08/23)
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- Diverse catalytic reactivity of a dearomatized PN3P?-nickel hydride pincer complex towards CO2 reduction
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A dearomatized PN3P?-nickel hydride complex has been prepared using an oxidative addition process. The first nickel-catalyzed hydrosilylation of CO2 to methanol has been achieved, with unprecedented turnover numbers. Selective methylation and formylation of amines with CO2 were demonstrated by such a PN3P?-nickel hydride complex, highlighting its versatile functions in CO2 reduction.
- Li, Huaifeng,Gon?alves, Théo P.,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
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supporting information
p. 11395 - 11398
(2018/10/20)
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- 1,4-Dioxane-Tuned Catalyst-Free Methylation of Amines by CO2 and NaBH4
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A catalyst-free reductive functionalization of CO2 with amines and NaBH4 was developed. The N-methylation of amines was carried out with CO2 as a C1 building block and 1,4-dioxane as the solvent. Notably, the six-electron reduction of CO2 to form the methyl group occurred simultaneously with formation of the C?N bond to give the N-methylated amine.
- Guo, Zhiqiang,Zhang, Bo,Wei, Xuehong,Xi, Chanjuan
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p. 2296 - 2299
(2018/07/31)
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- Tungstate catalysis: Pressure-switched 2- and 6-electron reductive functionalization of CO2 with amines and phenylsilane
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An efficient and environmentally benign tungstate catalyst for reductive functionalization of CO2 with amines and phenylsilane was developed. By simply varying the pressure, 2-electron or 6-electron reduction of CO2 was successfully achieved with simultaneous C-N bond formation, thus leading to the formation of formamides and methylamines, respectively. That is, secondary and primary amines furnished the corresponding methylamines or dimethylamines in excellent yields under atmospheric pressure of CO2, while various formamides were formed in yields ranging from 52% to 98% when increasing the CO2 pressure to 2 MPa. 1H NMR studies and control experiments demonstrate that N-formylation proceeds through the formation of silyl formate, while N-methylation proceeds through an aminal intermediate generated by 4-electron reduction of CO2.
- Wang, Mei-Yan,Wang, Ning,Liu, Xiao-Fang,Qiao, Chang,He, Liang-Nian
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supporting information
p. 1564 - 1570
(2018/04/12)
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- Preparation method of N-methylamine compound
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The invention discloses a preparation method of a N-methylamine compound. The preparation method comprises the following steps: under an inertia organic solvent or solvent-free condition and under a support-type nano-sized gold catalyst effect, a primary amine compound or a secondary amine compound is subjected to a N-methylation reaction with carbon dioxide and hydrogen to obtain the product. The preparation method takes CO2 as a methyl source, takes hydrogen as a reducing agent, and takes the support-type nano-gold as a catalyst, and has the advantages that process is simple, catalyst activity is high, reaction rate is fast, the catalyst recovery and utilization are convenient, the application scope of a substrate is wide, the production cost is low, the benifit is high, the post-treatment is simple, repeatability is good, safe performance is high, and environmental protection is achieved, and the method is adapted to industrial production.
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Paragraph 0094; 0095; 0096; 0099
(2017/08/19)
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- Method for selectively preparing N-monomethylamine compound
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The invention discloses a method for selectively preparing an N-monomethylamine compound. The method takes an amine compound, formaldehyde and H2 as reaction raw materials; the raw materials react in a reaction medium in the presence of a compound catalyst at 30 DEG C-180 DEG C for 2h-48h, so as to obtain the N-monomethylamine compound; and the compound catalyst is composed of oxides of at least two of the following metal or oxides of least one of the following metal and at least one metal simple substance: aluminum, copper, nickel, cobalt and iron. According to the method for preparing the N-monomethylamine compound, the conversion ratio and the selectivity of N-monomethylamine are relatively high; the H2 is used as a reducing agent and is clean, cheap and environment-friendly; the catalyst utilized by the method is cheap, simple to prepare and high in catalysis efficiency; and the method has mild preparation and reaction conditions and the catalyst has no corrosiveness, is easy to separate and can be repeatedly used.
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Paragraph 0027; 0034-0035
(2017/08/29)
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- N-acyl sulfamide FBPase inhibitor, preparation method thereof, drug composition and application
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The invention discloses an N-acryl sulfamide FBPase inhibitor of a novel structure, and a preparation method thereof, a drug composition and an application, and particularly relates to an N-acryl sulfamide FBPase inhibitor shown in the formula I, a salt thereof for medicine, a preparation method, a composition comprising one or more compounds, an application of the compound in preparing the FBPase inhibitor or a drug for treating FBPase-related diseases, and an application in preparing a drug for preventing and/or treating diabetes. The formula is shown in the description.
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Paragraph 2405; 2407; 2408
(2017/09/08)
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- RESORCINOL DERIVATIVE AS HSP90 INHIBITOR
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The present invention relates to a compound represented by formula (I) of a resorcinol derivative as an HSP90 inhibitor or pharmaceutically accepted salts thereof. The compound in the present invention has the activity of inhibiting heat shock protein HSP90. Therefore, the compound in the present invention is used to treat proliferative diseases such as cancer and neurodegenerative diseases. The present invention further provides the compounds and preparation methods for pharmaceutical compositions comprising the compounds, a method for treating diseases, and pharmaceutical compositions comprising the compounds.
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Paragraph 0076
(2017/12/27)
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- N-methylation of quinolines with CO2 and H2 catalyzed by Ru-triphos complexes
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N-methyl-tetrahydroquinolines (MTHQs) are a kind of very useful chemicals, which can be obtained from N-methylation of amines. However, the methylation of quinolines which is a kind of highly unsaturated nitrogen-containing heterocyclic aromatic compounds has not been reported. In this work, we report the first work for the synthesis of MTHQs by methylation of quinolines using CO2 and H2. It was found that Ru(acac)3-triphos [triphos: 1,1,1-tris(diphenylphosphinomethyl)ethanl] complex was very active and selective for the N-methylation reaction of quinolines, and the yield of the desired product could reach 99%.
- He, Zhenhong,Liu, Huizhen,Qian, Qingli,Lu, Lu,Guo, Weiwei,Zhang, Lujun,Han, Buxing
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p. 927 - 933
(2017/07/05)
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- Catalyst-free N-methylation of amines using CO2
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Recently, utilizing CO2 as a methylation reagent to construct functional chemicals has attracted significant attention. However, the conversion of CO2 is still a challenge due to its inherent inertness. In this study, we have developed a catalyst-free N-methylation of amines to prepare numerous methylamines using CO2 as a methyl source. By utilizing 2 eq. PhSiH3 as the reductant, amines could undergo N-methylation under 1 atm of CO2 in DMF at 90 °C. Aliphatic and aromatic amines were compatible, generating the desired products in up to 95% yield.
- Niu, Huiying,Lu, Lijun,Shi, Renyi,Chiang, Chien-Wei,Lei, Aiwen
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supporting information
p. 1148 - 1151
(2017/02/05)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 14848 - 14859
(2017/10/27)
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- α-Alkylation of tertiary amines by C(sp3)–C(sp3) cross-coupling under redox neutral photocatalysis
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Direct α-alkylation of N-phenyl-tetrahydroisoquinoline with alkyl selenides of desired alkyl chain length and functionality is reported by photoredox catalysis. Construction of hexahydro pyrrolo- and pyrido-isoquinoline scaffolds along with indolines and tetrahydroquinolines is also described by intramolecular C(sp3)–C(sp3) cross-couplings.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana
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p. 4480 - 4483
(2016/09/14)
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- Methylation of aromatic amines and imines using formic acid over a heterogeneous Pt/C catalyst
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We describe here a commercially available Pt/C catalyst capable of catalyzing the methylation of anilines and aromatic imines with formic acid in the presence of a hydrosilane reductant. Both primary aniline and secondary aniline can be methylated. The advantage of this newly described method includes operational simplicity, high TON, ready availability of the catalyst, and also good functional group compatibility.
- Zhu, Lei,Wang, Lian-Sheng,Li, Bojie,Li, Wei,Fu, Boqiao
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p. 6172 - 6176
(2016/08/19)
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- N-methylation of aromatic amines and N-heterocycles under acidic conditions with the TTT (1,3,5-trioxane-triethylsilane-trifluoroacetic acid) system
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A novel reductive N-methylation protocol under acidic conditions with the TTT (1,3,5-trioxane-triethylsilane-trifluoroacetic acid) system is disclosed. This method is highly specific for aromatic amines and several N-heterocycles (indoles and annulated analogues, phenoxazine, phenothiazine), insensitive to steric hindrance, and compatible with a wide range of functional groups. Further the N-methylation step can be combined with an in situ N-Boc deprotection. Compounds in which the nucleophilicity of the NH group is eliminated by protonation under the reaction conditions (aliphatic amines, azaarenes of noteworthy basicity) are inert. In several examples, it was demonstrated that the TTT system is complementary to other N-methylation protocols.
- Popp, Tobias A.,Bracher, Franz
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p. 3333 - 3338
(2016/11/29)
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- CARBOPYRONONE COMPOUNDS USEFUL AS DIAGNOSTIC ADJUVANTS
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Described herein are fluorescent compounds and methods and comprising these compounds. The compounds disclosed herein are carbopyronine reagents that fluoresce in the red portion of the UV/VIS spectrum and provide bright fluorescence intensity, uniform cell staining, and good retention within live cells as well as low toxicity toward cells.
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Page/Page column 103
(2016/01/27)
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- Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts
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The N-methylation of amines with CO2 and H2 is an important step in the synthesis of bioactive compounds and chemical intermediates. The first heterogeneous Au catalyst is reported for this methylation reaction with good to excellent yields. The average turnover frequency (TOF) based on surface Au atoms is 45 h-1, which is the highest TOF value ever reported for the methylation of aniline with CO2 and H2. Furthermore, the catalyst is tolerant toward a variety of amines, which includes aromatic, aliphatic, secondary, and primary amines. Preliminary mechanistic studies suggest that the N-alkyl formamide might be an intermediate in the N-methylation of amine process. Moreover, through a one-pot process, it is possible to convert primary amines, aldehydes, and CO2 into unsymmetrical tertiary amines with H2 as a reductant in the presence of the Au catalyst.
- Du, Xian-Long,Tang, Gao,Bao, Hong-Liang,Jiang, Zheng,Zhong, Xin-Hua,Su, Dang Sheng,Wang, Jian-Qiang
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p. 3489 - 3496
(2015/11/02)
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- Methylation of secondary amines with dialkyl carbonates and hydrosilanes catalysed by iron complexes
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Methylation of secondary amines was achieved using dimethyl carbonate or diethyl carbonate as the C1 source under the catalysis of well-defined half-sandwich iron complexes bearing an N-heterocyclic carbene ligand. The reaction proceeded under mild conditions in the presence of hydrosilanes as the reductants, and the amines were obtained with good to excellent isolated yields. This journal is
- Zheng, Jianxia,Darcel, Christophe,Sortais, Jean-Baptiste
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supporting information
p. 14229 - 14232
(2014/12/11)
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- A general method for N-methylation of amines and nitro compounds with dimethylsulfoxide
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DMSO methylates a broad range of amines in the presence of formic acid, providing a novel, green and practical method for amine methylation. The protocol also allows the one-pot transformation of aromatic nitro compounds into dimethylated amines in the presence of a simple iron catalyst. Not just a solvent: DMSO methylates a broad range of amines in the presence of formic acid, providing a novel, green and practical method for amine methylation. The protocol also allows the one-pot transformation of aromatic nitro compounds into dimethylated amines in the presence of a simple iron catalyst. Copyright
- Jiang, Xue,Wang, Chao,Wei, Yawen,Xue, Dong,Liu, Zhaotie,Xiao, Jianliang
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supporting information
p. 58 - 63
(2014/01/17)
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- Metal-free catalyst for the chemoselective methylation of amines using carbon dioxide as a carbon source
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N-methylation of amines is an important step in the synthesis of many pharmaceuticals and has been widely applied in the preparation of other key intermediates and chemicals. Therefore, the development of efficient methylation methods has attracted considerable attention. In this respect, carbon dioxide is an attractive C1 building block because it is an abundant, renewable, and nontoxic carbon source. Consequently, we developed a highly chemoselective, metal-free catalytic system that operates under ambient conditions for the N-methylation of amines. The methylation of amines with CO2 as C1 source and Ph2SiH2 as reducing agent was achieved with an N-heterocyclic carbene (NHC) as the catalyst. The catalyst is tolerant toward a variety of functional groups (including esters and ethers, nitro, nitrile, and carbonyl groups, and unsaturated C-C bonds); the reaction uses commercially available reagents and can be performed on a gram scale.
- Das, Shoubhik,Bobbink, Felix D.,Laurenczy, Gabor,Dyson, Paul J.
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supporting information
p. 12876 - 12879
(2016/02/18)
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- Sustainable heterogeneous platinum catalyst for direct methylation of secondary amines by carbon dioxide and hydrogen
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Pt and MoOx co-loaded TiO2 is found to be highly effective for direct methylation of aliphatic and aromatic secondary amines by CO2 and H2 under solvent-free conditions. This is the first additive-free and reusable heterogeneous catalytic system with acceptable turnover number. Over and over: A heterogeneous Pt catalyst for direct methylation of aromatic amines by CO2 and H2 with high reusability and an order of magnitude higher turnover number than previous catalysts has been demonstrated (see scheme).
- Kon, Kenichi,Siddiki, S. M. A. Hakim,Onodera, Wataru,Shimizu, Ken-Ichi
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p. 6264 - 6267
(2014/06/09)
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- An efficient one pot transfer hydrogenation and N-alkylation of quinolines with alcohols mediated by Pd/C/Zn
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A Pd/C/Zn mixture with alcohols has been revealed to be an efficient transfer hydrogenation system to quinolines. Furthermore, the metals mixture is able to activate alcohols as N-alkylating agents in a hydrogen autotransfer process. 1,2,3,4-Tetrahydroquinolines and N-alkylated tetrahydroquinolines from quinolines have been obtained with excellent yields in one step.
- Abarca, Belen,Adam, Rosa,Ballesteros, Rafael
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experimental part
p. 1826 - 1833
(2012/04/23)
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- ALKYL-SUBSTITUTED 3' COMPOUNDS HAVING 5-HT6 RECEPTOR AFFINITY
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The present disclosure provides compounds having affinity for the 5-HT6 receptor which are of the formula (I): wherein R1, R2, Ar, m and n are as defined herein. The disclosure also relates to methods of preparing such compounds, compositions containing such compounds, and methods of use thereof.
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Page/Page column 24
(2010/02/17)
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- CONDENSED HETEROCYCLIC COMPOUNDS HAVING 5-HT6 RECEPTOR AFFINITY
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The present disclosure provides compounds having affinity for the 5-HT6 receptor which are of the formula (I) wherein R1, A, B, D, E, G, Q, Ar, n, m, and p are as defined herein. The disclosure also relates to methods of preparing such compounds, compositions containing such compounds, and methods of use thereof.
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Page/Page column 66
(2010/04/03)
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- ACYCLIC COMPOUNDS HAVING 5-HT6 RECEPTOR AFFINITY
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The present disclosure provides compounds having affinity for the 5-HT6 receptor which are of the formula (I): wherein R1, R2, R5, Q, G, Ar, m, and n are as defined herein. The disclosure also relates to methods of preparing such compounds, compositions containing such compounds, and methods of use thereof.
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Page/Page column 51
(2010/03/02)
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