- Simple RuCl3-catalyzed N-Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol
-
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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- Reductive Arylation of Amides via a Nickel-Catalyzed Suzuki–Miyaura-Coupling and Transfer-Hydrogenation Cascade
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We report a means to achieve the addition of two disparate nucleophiles to the amide carbonyl carbon in a single operational step. Our method takes advantage of non-precious-metal catalysis and allows for the facile conversion of amides to chiral alcohols via a one-pot Suzuki–Miyaura cross-coupling/transfer-hydrogenation process. This study is anticipated to promote the development of new transformations that allow for the conversion of carboxylic acid derivatives to functional groups bearing stereogenic centers via cascade processes.
- Boit, Timothy B.,Mehta, Milauni M.,Kim, Junyong,Baker, Emma L.,Garg, Neil K.
-
supporting information
p. 2472 - 2477
(2020/12/03)
-
- NHC ligand-based half-sandwich iridium complexes: synthesis, structure and catalytic activity in acceptorless dehydrogenation and transfer hydrogenation
-
A set of neutral C,C-chelate half-sandwich iridium(iii) complexes have been prepared with NHC ligands that contain pendant aromatic rings as potentially chelating donor sites. The catalytic activity of such iridium complexes has been investigated for the acceptorless dehydrogenation (AD) reactions of alcohols and for the transfer hydrogenation reactions of ketones. The prepared iridium(iii) complexes show excellent catalytic activity for AD reactions of a wide range of secondary alcohols, and they are also shown to be effective for the synthesis of aldehydes from primary alcohols without the observation of undesired byproducts such as esters. Additionally, these complexes are also highly efficient in transfer hydrogenation of ketones and aldehydes, which give the alcohols in good yields under mild conditions. The exact structure and bonding mode of the NHC-based iridium complexes was identified using various spectroscopic methods and single crystal X-ray analysis.
- Deng, Wei,Jin, Yan,Li, Rong-Jian,Liu, Zhen-Jiang,Wang, Yang,Yao, Zi-Jian
-
p. 19002 - 19010
(2021/10/29)
-
- Ruthenium-Catalyzed Dehydrogenation of Alcohols with Carbodiimide via a Hydrogen Transfer Mechanism
-
Ruthenium-catalyzed oxidative dehydrogenation of alcohols using carbodiimide as an efficient hydrogen acceptor has been developed. The protocol exhibits wide substrate scope with good to excellent yields. The results of the kinetic analysis indicated that the reaction mechanism includes the hydrogen transfer process and that the addition of carbodiimide is essential for the reaction system, and the resulting amidine also could react as a hydrogen acceptor.
- Sueki, Shunsuke,Matsuyama, Mizuki,Watanabe, Azumi,Kanemaki, Arata,Katakawa, Kazuaki,Anada, Masahiro
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p. 4878 - 4885
(2020/06/02)
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- Amination of Aromatic Halides and Exploration of the Reactivity Sequence of Aromatic Halides
-
A base-promoted amination of aromatic halides has been developed using a limited amount of dimethylformamide (DMF) or amine as an amino source. Various aryl halides, including F, Cl, Br, and I, have been successfully aminated in good to excellent yields. Although the amination of aromatic halides with amines or DMF is usually considered as an aromatic nucleophilic substitution (SNAr) process, and the reactivity of an aromatic halide is F > Cl > Br > I, the reactivity of aromatic halides in this system was found to be I > Br a‰ F > Cl. This protocol also showed a good regioselectivity for multihalogenated aromatics. This protocol is valuable for industrial application due to the simplicity of operation, the unrestricted availability of amino sources and aromatic halides, transition metal-free conditions, no requirement for solvent, and scalability.
- Yang, Chu,Zhang, Feng,Deng, Guo-Jun,Gong, Hang
-
p. 181 - 190
(2019/01/10)
-
- Tropylium Ion Catalyzes Hydration Reactions of Alkynes
-
The hydration of alkynes is one of the most atom-economic and versatile synthetic protocols to access carbonyl compounds. This fundamental reaction, however, often requires transition-metal catalysts or harsh reaction conditions to promote the addition of water to the carbon–carbon triple bond. In this work, it is demonstrated that the non-benzenoid aromatic tropylium ion can be used as an organic Lewis acid promoter for the hydration of alkynes under simple reaction conditions with excellent outcomes.
- Oss, Giulia,Ho, Junming,Nguyen, Thanh Vinh
-
supporting information
p. 3974 - 3981
(2018/08/17)
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- Preparation method of aromatic ketone
-
The invention discloses a preparation method of aromatic ketone. Under the effects of a palladium catalyst and a nitrogen-containing ligand, nitrile compounds and arylsulfonylhydrazide take desulfurization addition reaction in an organic solvent; after the reaction is completed, post treatment is performed to obtain aromatic ketone. The reaction is applicable to aromatic nitrile compounds, and isalso applicable to aliphatic nitrile compounds; the reaction realizes the wide substrate applicability and functional group tolerance; the potential application value is realized in the aspect of aryl-carbonyl building.
- -
-
Paragraph 0056; 0057; 0058; 0060
(2018/09/11)
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- Pd(II)-Catalyzed Denitrogenative and Desulfinative Addition of Arylsulfonyl Hydrazides with Nitriles
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A Pd(II)-catalyzed denitrogenative and desulfinative addition of arylsulfonyl hydrazides with nitriles has been successfully achieved under mild conditions. This transformation is a new method for the addition reaction to nitriles with arylsulfonyl hydrazides as arylating agent, thus providing an alternative synthesis of aryl ketones. The reported addition reaction is tolerant to many common functional groups, and works well in the presence of electron-donating and electron-withdrawing substituents. Notably, the reported denitrogenative and desulfinative addition was also appropriate for alkyl nitriles, making this newly developed transformation attractive.
- Meng, Mengting,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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p. 3275 - 3284
(2018/03/25)
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- Design, synthesis and biological evaluation of novel aryldiketo acids with enhanced antibacterial activity against multidrug resistant bacterial strains
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Antimicrobial resistance (AMR) is a major health problem worldwide, because of ability of bacteria, fungi and viruses to evade known therapeutic agents used in treatment of infections. Aryldiketo acids (ADK) have shown antimicrobial activity against several resistant strains including Gram-positive Staphylococcus aureus bacteria. Our previous studies revealed that ADK analogues having bulky alkyl group in ortho position on a phenyl ring have up to ten times better activity than norfloxacin against the same strains. Rational modifications of analogues by introduction of hydrophobic substituents on the aromatic ring has led to more than tenfold increase in antibacterial activity against multidrug resistant Gram positive strains. To elucidate a potential mechanism of action for this potentially novel class of antimicrobials, several bacterial enzymes were identified as putative targets according to literature data and pharmacophoric similarity searches for potent ADK analogues. Among the seven bacterial targets chosen, the strongest favorable binding interactions were observed between most active analogue and S. aureus dehydrosqualene synthase and DNA gyrase. Furthermore, the docking results in combination with literature data suggest that these novel molecules could also target several other bacterial enzymes, including prenyl-transferases and methionine aminopeptidase. These results and our statistically significant 3D QSAR model could be used to guide the further design of more potent derivatives as well as in virtual screening for novel antibacterial agents.
- Cvijeti?, Ilija N.,Verbi?, Tatjana ?.,Ernesto de Resende, Pedro,Stapleton, Paul,Gibbons, Simon,Jurani?, Ivan O.,Drakuli?, Branko J.,Zloh, Mire
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p. 1474 - 1488
(2017/11/17)
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- Micellar catalysis-enabled sustainable ppm Au-catalyzed reactions in water at room temperature
-
Several ppm level gold-catalyzed reactions enabled by the ligand HandaPhos can be performed at room temperature in aqueous nanoreactors composed of the surfactant Nok. Variously substituted allenes undergo cycloisomerization leading to heterocyclic products in good yields. Likewise, cyclodehydration is also illustrated under similar conditions, as is an intermolecular variant, hydration of terminal alkynes. Recycling of the catalyst and reaction medium is also illustrated. A low E factor associated with limited solvent use and therefore, waste generation, documents the greenness of this process.
- Klumphu, Piyatida,Desfeux, Camille,Zhang, Yitao,Handa, Sachin,Gallou, Fabrice,Lipshutz, Bruce H.
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p. 6354 - 6358
(2017/08/29)
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- P -Selective (sp2)-C-H functionalization for an acylation/alkylation reaction using organic photoredox catalysis
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p-Selective (sp2)-C-H functionalization of electron rich arenes has been achieved for acylation and alkylation reactions, respectively, with acyl/alkylselenides by organic photoredox catalysis involving an interesting mechanistic pathway.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana,Vanka, Kumar,Jain, Shailja
-
supporting information
p. 12337 - 12340
(2017/11/20)
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- A Mechanochemical-Assisted Oxidation of Amines to Carbonyl Compounds and Nitriles
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A mild, efficient, metal- and solvent-free oxidation of primary amines to aldehydes, ketones, and nitriles under ball-milling conditions is presented. This method has proved to be compatible with various functional groups and only requires easily accessible starting materials. Simple purification of the reaction mixtures by short-column chromatography afforded pure aldehydes, ketones, and nitriles as products.
- Gaspa, Silvia,Porcheddu, Andrea,Valentoni, Antonio,Garroni, Sebastiano,Enzo, Stefano,De Luca, Lidia
-
supporting information
p. 5519 - 5526
(2017/09/06)
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- Efficient and Selective N-Methylation of Nitroarenes under Mild Reaction Conditions
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Herein, we report a straightforward protocol for the preparation of N,N-dimethylated amines from readily available nitro starting materials using formic acid as a renewable C1 source and silanes as reducing agents. This tandem process is efficiently accomplished in the presence of a cubane-type Mo3PtS4 catalyst. For the preparation of the novel [Mo3Pt(PPh3)S4Cl3(dmen)3]+ (3+) (dmen: N,N′-dimethylethylenediamine) compound we have followed a [3+1] building block strategy starting from the trinuclear [Mo3S4Cl3(dmen)3]+ (1+) and Pt(PPh3)4 (2) complexes. The heterobimetallic 3+ cation preserves the main structural features of its 1+ cluster precursor. Interestingly, this catalytic protocol operates at room temperature with high chemoselectivity when the 3+ catalyst co-exists with its trinuclear 1+ precursor. N-heterocyclic arenes, double bonds, ketones, cyanides and ester functional groups are well retained after N-methylation of the corresponding functionalized nitroarenes. In addition, benzylic-type as well as aliphatic nitro compounds can also be methylated following this protocol.
- Pedrajas, Elena,Sorribes, Iván,Guillamón, Eva,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
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p. 13205 - 13212
(2017/09/12)
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- Acceptorless Dehydrogenation of Alcohols Catalyzed by CuI N-Heterocycle Thiolate Complexes
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CuI N-heterocycle thiolate clusters efficiently catalyze the acceptorless dehydrogenation of alcohols at 70 °C. A variety of secondary/primary benzylic, allylic, and aliphatic alcohols are dehydrogenated to the corresponding ketones and aldehydes in high yields of isolated product upon release of H2. This simple catalytic system is involved in the synthesis of imines through the one-pot reaction of alcohols and amines.
- Tan, Da-Wei,Li, Hong-Xi,Zhang, Meng-Juan,Yao, Jian-Lin,Lang, Jian-Ping
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p. 1113 - 1118
(2017/03/27)
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- Cuprous compound based on nitrogen heterocyclic thiol ligand and preparation method and application of cuprous compound
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The invention discloses a cuprous compound based on a nitrogen heterocyclic thiol ligand and a preparation method and application of the cuprous compound. The cuprous compound based on the nitrogen heterocyclic thiol ligand is shown as a chemical formula [Cu6(pyt)6], wherein pyt refers to a negative ion formed by proton loss of sulfydryl in 2-mercaptopyridine. The cuprous compound based on the nitrogen heterocyclic thiol ligand is capable of catalyzing conversion of alcohol compounds into aldehyde compounds and ketone compounds, and has the advantages of high conversion efficiency, wide applicable range, mild reaction conditions and the like.
- -
-
Paragraph 0027
(2017/05/13)
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- General method for nucleophilic aromatic substitution of aryl fluorides and chlorides with dimethylamine using hydroxide-assisted decomposition of N,N-dimethylforamide
-
A practical and convenient procedure for the nucleophilic aromatic substitution of aryl fluorides and chlorides with dimethylamine was developed using a hydroxide-assisted thermal decomposition of N,N-dimethylforamide. These conditions are tolerant of nitro, nitrile, aldehyde, ketone, and amide groups but will undergo acyl substitution to form amides for methyl esters and acyl chlorides. Isolated yields of the products range from 44% to 98%, with the majority being greater than 70% for 17 examples.
- Garcia, Juana,Sorrentino, Jacob,Diller, Emily J.,Chapman, Daniel,Woydziak, Zachary R.
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supporting information
p. 475 - 481
(2016/04/05)
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- Selective formylation and methylation of amines using carbon dioxide and hydrosilane catalyzed by alkali-Metal carbonates
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The formylation and methylation of amines with carbon dioxide and hydrosilanes are emerging yet important types of transformations for CO2. Catalytic methods effective for both reactions with wide substrate scopes are rare because of the difficulty in controlling the selectivity. Herein, we report that simple and readily available inorganic bases alkali-metal carbonates, especially cesium carbonatecatalyze both the formylation and methylation reactions efficiently under mild conditions. The selectivity can be conveniently controlled by varying the reaction temperature and silane. A “cesium effect” on both reactions was observed by comparing the catalytic activity of various alkali-metal carbonates. Combined experimental and computational studies suggested the following reaction mechanism: (i) activation of Si?H by Cs2CO3, (ii) insertion of CO2 into Si?H, (iii) formylation of amines by silyl formate, and (iv) reduction of formamides to methylamines.
- Fang, Chi,Lu, Chunlei,Liu, Muhua,Zhu, Yiling,Fu, Yao,Lin, Bo-Lin
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p. 7876 - 7881
(2018/05/23)
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- Metal-Free Intermolecular Coupling of Arenes with Secondary Amides: Chemoselective Synthesis of Aromatic Ketimines and Ketones, and N-Deacylation of Secondary Amides
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The direct transformation of common secondary amides into aromatic ketimines and aromatic ketones with C-C bond formation is described. The reaction can also be used for N-deacylation of secondary amides to release amines. This method consists of in situ amide activation with triflic anhydride and intermolecular capture of the resulting highly electrophilic nitrilium intermediate with an arene. The reaction is applicable to various kinds of secondary amides (electrophiles), but only electron-rich and moderately electron-rich arenes can be used as nucleophiles. Thanks to the use of bench stable arenes instead of reactive and basic organometallics as nucleophiles, the reaction proceeded with high chemoselectivity at the secondary amido group in the presence of a series of sensitive functional groups such as aldehyde, ketone, ester, cyano, nitro, and tertiary amido groups. The reaction can be viewed as a Friedel-Crafts-type reaction using secondary amides as acylating agents or as an intermolecular version of the Bischler-Napieralski reaction.
- Huang, Pei-Qiang,Huang, Ying-Hong,Xiao, Kai-Jiong
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p. 9020 - 9027
(2016/10/17)
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- Reductive N-methylation of amines with calcium hydride and Pd/C catalyst
-
The methylation of amines by paraformaldehyde in the presence of calcium hydride as a source of hydrogen and palladium on charcoal as catalyst was studied. Depending on the quantity of paraformaldehyde, monomethylated and dimethylated amines were selectively and efficiently prepared in one pot with good yields.
- Guyon, Carole,Duclos, Marie-Christine,Métay, Estelle,Lemaire, Marc
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p. 3002 - 3005
(2016/07/06)
-
- Design, synthesis and pharmacology of 1,1-bistrifluoromethylcarbinol derivatives as liver X receptor β-selective agonists
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A novel series of 1,3-bistrifluoromethylcarbinol derivatives that act as liver X receptor (LXR) β-selective agonists was discovered. Structure-activity relationship studies led to the identification of molecule 62, which was more effective (Emax) and selective toward LXRβ than T0901317 and GW3965. Furthermore, 62 decreased LDL-C without elevating the plasma TG level and significantly suppressed the lipid-accumulation area in the aortic arch in a Bio F1B hamster fed a diet high in fat and cholesterol. We demonstrated that our LXRβ agonist would be potentially useful as a hypolipidemic and anti-atherosclerotic agent. In this manuscript, we report the design, synthesis and pharmacology of 1,3-bistrifluoromethylcarbinol derivatives.
- Koura, Minoru,Matsuda, Takayuki,Okuda, Ayumu,Watanabe, Yuichiro,Yamaguchi, Yuki,Kurobuchi, Sayaka,Matsumoto, Yuuki,Shibuya, Kimiyuki
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p. 2668 - 2674
(2015/06/08)
-
- Z-selective, anti-Markovnikov addition of alkoxides to terminal alkynes: An electron transfer pathway?
-
Potassium alkoxides undergo anti-Markovnikov addition to aryl-substituted alkynes with Z selectivity in DMF as the solvent. The yields and efficiency of the reaction was also found to be enhanced by the addition of a secondary amine ligand such as N,N′-di
- Cuthbertson, James,Wilden, Jonathan D.
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p. 4385 - 4392
(2015/06/08)
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- Room-temperature copper-catalyzed arylation of dimethylamine and methylamine in neat water
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The first room-temperature copper-catalyzed arylations of dimethylamine and methylamine in neat water have been developed. Using a combination of CuI and 6,7-dihydroquinolin-8(5 H)-one oxime as catalyst, dimethylamine is arylated with various aryl halides to give the corresponding products in good to excellent yields. Further, this catalysis enables the selective arylation of methylamine to afford the high yields of monoarylated methylamines as the sole products.
- Wang, Deping,Kuang, Daizhi,Zhang, Fuxing,Yang, Chunlin,Zhu, Xiaoming
-
supporting information
p. 714 - 718
(2015/03/18)
-
- Ligand- and Acid-Free Gold(I) Chloride Catalyzed Hydration of Terminal Alkynes
-
Our work shows that simple alkynes can be hydrated by the AuCl/MeOH catalyst system to afford the corresponding methyl ketones in moderate to high yields without any additive, ligand, or acid promoter. This methodology is simpler, milder, and operationally easier than those reported before. The reaction media significantly affects the reaction, and methanol is found to be the best solvent. Both aliphatic and aromatic terminal alkynes were able to undergo hydration, affording moderate to excellent yields under the reaction conditions used in the present work, and excellent functional-group tolerance was also observed. A plausible mechanism for the hydration reaction was proposed.
- Das, Atanu Kumar,Park, Sangseung,Muthaiah, Senthilkumar,Hong, Soon Hyeok
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p. 2517 - 2520
(2015/11/16)
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- Tuning of the excitation wavelength in Eu3+-aminophenyl based polyfluorinated β-diketonate complexes: a red-emitting Eu3+-complex encapsulated in a silica/polymer hybrid material excited by blue light
-
We describe herein the synthesis, characterization and photophysical properties of a series of europium complexes based on three aminophenyl based polyfluorinated β-diketonates, namely, 1-(4-aminophenyl)-4,4,5,5,5-pentafluoro-3-hydroxypent-2-en-1-one, 1-(
- Usha Gangan,Reddy
-
p. 15924 - 15937
(2015/09/15)
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- Direct catalytic cross-coupling of alkenyllithium compounds
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A catalytic method for the direct cross-coupling of alkenyllithium reagents with aryl and alkenyl halides is described. The use of a catalyst comprising Pd2(dba)3/XPhos allows for the stereoselective preparation of a wide variety of substituted alkenes in high yields under mild conditions. In addition (1-ethoxyvinyl)lithium can be efficiently converted into substituted vinyl ethers which, after hydrolysis, give readily access to the corresponding methyl ketones in a one pot procedure.
- Hornillos, Valentn,Giannerini, Massimo,Vila, Carlos,Faans-Mastral, Martn,Feringa, Ben L.
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p. 1394 - 1398
(2015/02/19)
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- Asymmetric Reduction of Electron-Rich Ketones with Tethered Ru(II)/TsDPEN Catalysts Using Formic Acid/Triethylamine or Aqueous Sodium Formate
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The asymmetric transfer hydrogenation (ATH) of ketones under aqueous conditions using tethered Ru(II)/6-arene/diamine catalysts is described, as is the ATH of electron-rich substrates containing amine and methoxy groups on the aromatic rings. Although such substrates are traditionally challenging ones for ATH, the tethered catalysts work very efficiently. In the case of amino-substituted ketones, aqueous conditions give excellent results; however, for methoxy-substituted substrates, the more established formic acid/triethylamine system gives superior results.
- Soni, Rina,Hall, Thomas H.,Mitchell, Benjamin P.,Owen, Matthew R.,Wills, Martin
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p. 6784 - 6793
(2015/10/06)
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- Hydration of aromatic terminal alkynes catalyzed by iron(III) sulfate hydrate under chlorine-free conditions
-
The hydration of aromatic terminal alkynes performed in acetic acid in the presence of catalytic hydrate ironIII sulfate, Fe2(SO 4)3·nH2O (4-9 mol %), yields the derived aryl methyl ketones with good to excellent yields. Under comparable conditions (18 mol %, 95 C, 24 h), bifunctional substrates were transformed into the monoacetyl or the diacetyl derivatives, depending on the structure of the aromatic diyne. The reaction is compatible with aryl substituents of different nature and ring positions, including hydroxyl, carbonyl groups, and cumulated hydrocarbons. The soft character of the non nucleophilic sulfate anion allows for activation of the triple bond toward carbonoxygen bond formation in the Br?nsted acidic medium. The proposed protocol is based on readily available and non toxic materials, in the absence of chlorine atoms in either the solvent or the metal catalyst.
- Bassetti, Mauro,Ciceri, Samuele,Lancia, Federico,Pasquini, Chiara
-
supporting information
p. 1608 - 1612
(2014/03/21)
-
- Synthesis and biological evaluation of some new pyrazoline substituted benzenesulfonylurea/thiourea derivatives as anti-hyperglycaemic agents and aldose reductase inhibitors
-
Seventeen new pyrazoline substituted benzenesulfonylurea/thiourea derivatives (2a-q) were synthesized and characterized by elemental analysis and various spectroscopic techniques viz; IR, 1H NMR, 13C NMR, and MS data. Thirteen compounds showed moderate to good anti-hyperglycaemic activity in glucose fed hyperglycaemic normal rats at the dose of 0.05 mM/kg b.w. On the basis of docking results nine compounds (2a, 2c, 2e, 2h, 2k, 2l, 2n, 2o and 2q) were evaluated for their ability to inhibit rat lens aldose reductase. Out of these six compounds (2h, 2k, 2l, 2n, 2o and 2q) were found more effective than the known ARI sorbinil. Five compounds (2h, 2k, 2l, 2n and 2o) showed significant dual action (anti-hyperglycaemic and aldose reductase inhibition).
- Ovais, Syed,Pushpalatha,Reddy, G. Bhanuprakash,Rathore, Pooja,Bashir, Rafia,Yaseen, Shafiya,Dheyaa, Alhamza,Yaseen, Raed,Tanwar, Omprakash,Akthar, Mymoona,Samim, Mohammed,Javed, Kalim
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p. 209 - 217
(2014/05/20)
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- A simple approach to aggregation-induced emission in difluoroboron dibenzoylmethane derivatives
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The first example of an AIE active BF2dbm derivative with a single dimethylamino group connecting to the phenyl ring was revealed. It also showed capability of sensing HCl gas both in solution and in the solid state.
- Hu, Junyi,He, Zhen,Wang, Zhi,Li, Xiaoyu,You, Jingsong,Gao, Ge
-
supporting information
p. 4167 - 4170
(2013/07/26)
-
- Ruthenium-catalyzed transfer hydrogenation of amino- and amido-substituted acetophenones
-
The ruthenium-catalyzed transfer hydrogenation of electron-rich amino-substituted acetophenones is reported. Variation of the reductant, ligands, base, and solvent allowed reaction optimization. A key discovery was the use of 1,4-butanediol as an irreversible reducing agent, which significantly improved the conversion. A range of amino- and amido-substituted aryl ketones were explored, and they all gave the corresponding alcohols in good yield, which demonstrates the wider applicability of this process. The ruthenium-catalyzed reduction of electron-rich amino-substituted acetophenones with 1,4-butanediol as an irreversible reducing agent is reported. Optimization of the conditions and variation of the amino substituent are explored as is the use of amido- and sulfonamidoacetophenones with varying results. Copyright
- Watson, Andrew J. A.,Fairbanks, Antony J.
-
supporting information
p. 6784 - 6788
(2013/11/06)
-
- Efficient and recyclable rare earth-based catalysts for Friedel-Crafts acylations under microwave heating: Dendrimers show the way
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The catalytic system involving Sc(OTf)3 and a dendritic terpyridine ligand is able to promote the Friedel-Crafts acylation of a wide range of aromatics under microwave irradiation. The expected products are obtained in high yields after short reaction times and the nano-sized catalyst can be recovered and successfully used in 12 consecutive runs.
- Perrier, Arnaud,Keller, Michel,Caminade, Anne-Marie,Majoral, Jean-Pierre,Ouali, Armelle
-
supporting information
p. 2075 - 2080
(2013/09/24)
-
- One-pot synthesis of N,N-dimethylanilines from nitroarenes with skeletal Cu as chemoselective catalyst
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A range of N,N-dimethylanilines were synthesized with excellent yields in one-pot by the hydrogenation and alkylation of nitroarenes with H2 and HCHO over quenched skeletal Cu catalyst, which provides a facile, economical, and environmentally benign alternative methodology for C-N bonds formation.
- Rong, Zeming,Zhang, Wenjun,Zhang, Peng,Sun, Zhuohua,Lv, Jinkun,Du, Wenqiang,Wang, Yue
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p. 115 - 118
(2013/09/02)
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- Aerobic oxidative kinetic resolution of secondary alcohols with naphthoxide-bound iron(salan) complex
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The first general method for iron-catalyzed aerobic oxidative kinetic resolution of secondary alcohols was achieved with good to high enantiomeric differentiation (krel = 7-50). Although iron(salan) complex 1 does not catalyze alcohol oxidation, the naphthoxide-bound iron(salan) complex does.
- Kunisu, Takashi,Oguma, Takuya,Katsuki, Tsutomu
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experimental part
p. 12937 - 12939
(2011/10/02)
-
- Rh- and Ru-complex-catalyzed dimerization of arylethynes Rylethynes in aqueous environment
-
Complexes [RhCl(PPh3)3] and [Ru(CHPh)Cl 2(PCy3)2] efficiently catalyzed the dimerization of arylethynes to the corresponding 1,4-substituted enynes in aqueous environment in the presence of sodium dodecyl sulfate. The Rh catalyst exhibited almost exclusive preference for the formation of ￡-isomers, the Ru one exhibits strong preference for the formation of Z-isomers.
- Novak, Petr,Kotora, Martin
-
experimental part
p. 433 - 442
(2009/07/17)
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- Synthesis of 5-aryl-5′-formyl-2,2′-bithiophenes as new precursors for nonlinear optical (NLO) materials
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A series of formyl-substituted 5-aryl-2,2′-bithiophenes 5 were synthesized using two different methods: Vilsmeier-Haack-Arnold reaction (VHA) or through Suzuki coupling. The synthesis of compounds 5 through the Vilsmeier-Haack-Arnold reaction, starting from inexpensive and easily available precursors such as acetophenones, gave the title compounds in low yields after four reaction steps. On the other hand Suzuki coupling of functionalized arylboronic acids 7 and the 5-bromo-5′-formyl-2,2′-bithiophene 6 gave compounds 5 in good yields in only one step.
- Herbivo, Cyril,Comel, Alain,Kirsch,Raposo, M. Manuela M.
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experimental part
p. 2079 - 2086
(2009/07/18)
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- Structure-activity relationship study of a novel necroptosis inhibitor, necrostatin-7
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Necroptosis is a regulated caspase-independent cell death mechanism characterized by morphological features resembling non-regulated necrosis. Necrotatin-7 (Nec-7), a novel potent small-molecule inhibitor of necroptosis, is structurally distinct from previously described necrostatins (Nec-1, Nec-3, Nec-4 and Nec-5). Here, we describe a series of structural modifications and the structure-activity relationship (SAR) of the Nec-7 series for inhibiting necroptosis.
- Zheng, Weihong,Degterev, Alexei,Hsu, Emily,Yuan, Junying,Yuan, Chengye
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body text
p. 4932 - 4935
(2009/05/26)
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- Lanthanide triflate-catalyzed arene acylation. Relation to classical Friedel-Crafts acylation
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(Chemical Equation Presented) Lanthanide trifluoromethanesulfonates, Ln(OTf)3 (OTf- = trifluoromethanesulfonate), serve as effective precatalysts for the rapid, regioselective, intermolecular acylation of activated arenes. This contribution probes mechanism and metal ionic radius effects in the catalytic lanthanide triflate-mediated acylation of anisole with acetic anhydride. Kinetic studies of Ln(OTf)3 (Ln = La, Eu, Yb, Lu)-mediated anisole acylation with acetic anhydride in nitromethane reveal the rate law ν ～ k3 [Ln3+]1[acetic anhydride]1[anisole]1. Eyring and Arrhenius analyses yield ΔH? = 12.9 (4) kcal·mol-1, ΔS? = -44.8 (1.3) e.u., and Ea = 13.1 (4) kcal·mol-1 for Ln = Yb, with the negative ΔS? implying a highly organized transition state. The observed primary kinetic isotope effect of k H/kD = 2.6 ± 0.15 is consistent with arene C-H bond scission in the turnover-limiting step. The proposed catalytic pathway involves precatalyst formation via interaction of Ln(OTf)3 with acetic anhydride, followed by Ln3+-anisole π-complexation, substrate-electrophile σ-complex formation, and turnover-limiting C-H bond scission. Lanthanide size effects on turnover frequencies are consistent with a transition state lacking significant ionic radius-dependent steric constraints. Substrate-Ln3+ interactions using paramagnetic Gd3+ and Yb3+ NMR probes and factors affecting reaction rates such as arene substituent and added LiClO4 cocatalyst are also explored.
- Dzudza, Alma,Marks, Tobin J.
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p. 4004 - 4016
(2008/09/21)
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- Compounds and amyloid probes thereof for therapeutic and imaging uses
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The present invention provides compounds and amyloid probes thereof that allow for an antemortem method of diagnosing AD and quantitating the extent or progression of amyloid deposits (plaques) by in vivo imaging of amyloid and/or amyloid deposits in the
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Page/Page column 28; 39
(2008/06/13)
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- Stereoselective syntheses of fluorescent non-natural aromatic amino acids based on asymmetric michael additions
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Four fluorescent non-natural aromatic amino acids have been synthesized based on a key stereoselective Michael addition reaction. S-1-Phenylethylamine was employed as both the source of amine and the stereoselectivity controller. The overall yields were m
- Chen, Heru,Zhong, Xianbin,Wei, Jin
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p. 1170 - 1182
(2008/02/05)
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- 2-Hydroxymethyl-4-[5-(4-methoxyphenyl)-3-trifluoromethyl-1H-1-pyrazolyl] -1-benzenesulfonamide (DRF-4367): An orally active COX-2 inhibitor identified through pharmacophoric modulation
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Analogs of 1,5-diarylpyrazoles with a novel pharmacophore at N1 were designed, synthesized and evaluated for the in-vitro cyclooxygenase (COX-1/COX-2) inhibitory activity. The variations at/around position-4 of the C-5 phenyl ring in conjunction with a CF3 and CHF2 groups at C-3 exhibited a high degree of potency and selectivity index (SI) for COX-2 inhibition. The in-vivo evaluation of these potent compounds with a few earlier ones indicated the 4-OMe-phenyl analog 6 and the 4-NHMe-phenyl analog 9 with a CF3, and the 4-OEt-phenyl analog 19 with a CHF2 group at C-3 to possess superior potency than celecoxib. In addition to its impressive anti-inflammatory, antipyretic, analgesic and anti-arthritic properties, compound 6 (DRF-4367) was found to possess an excellent pharmacokinetic profile, gastrointestinal (GI) safety in the long-term arthritis study and COX-2 potency in human whole blood assay. Thus, compound 6 was selected as an orally active anti-inflammatory candidate for pre-clinical evaluation.
- Singh, Sunil Kumar,Vobbalareddy, Saibaba,Kalleda, Srinivasa Rao,Rajjak, Shaikh Abdul,Casturi, Seshagiri Rao,Datla, Srinivasa Raju,Mamidi, Rao N.V.S.,Mullangi, Ramesh,Bhamidipati, Ravikanth,Ramanujam, Rajagopalan,Akella, Venkateswarlu,Yeleswarapu, Koteswar Rao
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p. 2442 - 2450
(2007/10/03)
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- Synthesis and Evaluation of Two 18F-Labeled 6-Iodo-2-(4′ -N,N-dimethylamino)phenylimidazo[1,2-a]pyridine Derivatives as Prospective Radioligands for β-Amyloid in Alzheimer's Disease
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This study evaluated 18F-labeled IMPY [6-iodo-2-(4′ -N,N-dimethylamino)phenylimidazo[1,2-a]pyridine] derivatives as agents for imaging β-amyloid plaque with positron emission tomography (PET). The precursor for radiolabeling and reference compounds was synthesized in up to five steps from commercially accessible starting materials. One of the two N-methyl groups of IMPY was substituted with either a 3-fluoropropyl (FPM-IMPY) or a 2-fluoroethyl (FEM-IMPY) group. FPM-IMPY and FEM-IMPY were found to have moderate affinity for Aβ-aggregates with Ki = 27 ± 8 and 40 ± 5 nM, respectively. A "one-pot" method for 18F-2-fluoroethylation and 18F-3-fluoropropylation of the precursor was developed. The overall decay-corrected radiochemical yields were 26-51%. In PET experiments with normal mouse, high uptake of activity was obtained in the brain after iv injection of each probe: 6.4% ID/g for [ 18F]FEM-IMPY at 1.2 min, and 5.7% ID/g for [18F]FPM-IMPY at 0.8 min. These values were similar to those of [123I/ 125I]IMPY (7.2% ID/g at 2 min). Polar and nonpolar radioactive metabolites were observed in both plasma and brain homogenates after injection of [18F]FEM or [18F]FPM-IMPY. In contrast to the single-exponential washout of [123I/125I]IMPY, the washouts of brain activity for the two fluorinated analogues were biphasic, with an initial rapid phase over 20 min and a subsequent much slower phase. Residual brain activity at 2 h, which may represent polar metabolites trapped in the brain, was 4.5% ID/g for [18F]FEM-IMPY and 2.1% ID/g for [18F]FPM-IMPY. Substantial skull uptake of [18F]fluoride was also clearly observed. With a view to slow the metabolism of [ 18F]FEM-IMPY, an analogue was prepared with deuteriums substituted for the four ethyl hydrogens. However, D4-[18F]FEM-IMPY showed the same brain uptake and clearance as the protio analogue. Metabolism of the [18F]FEM-IMPY was appreciably slower in rhesus monkey than in mouse. Autoradiography of postmortem brain sections of human Alzheimer's disease patients with [18F]FEM-IMPY showed high displaceable uptake in gray matter and low nonspecific binding in the white matter. This study demonstrates that the IMPY derivatives have favorable in vivo brain pharmacokinetics and a moderate affinity for imaging β-amyloid plaques; however, further improvements are needed to reduce radioactive metabolites, increase binding affinity, and reduce lipophilicity.
- Cai, Lisheng,Chin, Frederick T.,Pike, Victor W.,Toyama, Hiroshi,Liow, Jeih-San,Zoghbi, Sami S.,Modell, Kendra,Briard, Emmanuelle,Shetty, H. Umesha,Sinclair, Kathryn,Donohue, Sean,Tipre, Dnyanesh,Kung, Mei-Ping,Dagostin, Claudio,Widdowson, David A.,Green, Michael,Gao, Weiyi,Herman, Mary M.,Ichise, Masanori,Innis, Robert B.
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p. 2208 - 2218
(2007/10/03)
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- 1-(Aromatic- or heteroaromatic-substituted)-3-(heteroaromatic substituted)-1,3-propanediones and uses thereof
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Certain 1-(aromatic- or heteroaromatic-substituted-3-(heteroaromatic substituted)-1,3-propanediones are described as inhibitors of HIV integrase and inhibitors of HIV replication. These compounds are useful in the prevention or treatment of infection by HIV and the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.
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- Intramolecular sensitisation of lanthanide(III) luminescence by acetophenone-containing ligands: The critical effect of para-substituents and solvent
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Tetraazamacrocyclic ligands have been prepared in which three of the four nitrogen atoms are functionalised with carboxylate donors and the fourth is alkylated with apara-substituted acetophenone group {-CH2C(O)C6H4-X, whe
- Beeby, Andrew,Bushby, Lisa M.,Maffeo, Davide,Gareth Williams
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- Photoinduced electron transfer retropinacol reaction of 4-(N,N-dimethylamino)phenyl pinacols in chloroform
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UV irradiation of 1,2-bis[4-N,N-(dimethylamino)phenyl]ethane-1,2-diol (1a) and 2,3-bis[4-(N,N-dimethylamino)phenyl]butane-2,3-diol (1b) in deaerated chloroform leads to central carbon-carbon bond cleavage (retropinacol reaction) forming 4-(N,N-dimethylami
- Zhang, Wei,Yang, Li,Wu, Long-Min,Liu, You-Cheng,Liu, Zhong-Li
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p. 1189 - 1193
(2007/10/03)
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- Time-resolved fluorescence and transient spectroscopy in determining photochemical and photophysical channels in reacting systems in solutions and microheterogeneous media
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Characterization of short-lived intermediates in homogeneous and microheterogeneous systems has been carried out using time-resolved spectroscopic techniques. The data obtained from these techniques have been analyzed in a relatively unconventional manner to elucidate complex transient behavior for two reactive systems. The highly nonexponential fluorescence decay for a series of trans-stilbene-derivatized amphiphiles that readily form bilayer systems in aqueous media has been analyzed using a distribution of lifetimes analysis (DLA). The utility of DLA for quantitative studies was first determined by simulation of artificial decay data. Despite some limitations in DLA, qualitative conclusions as to the nature of the fluorescing species may be drawn when supplementary information such as steady-state spectroscopic data are also considered. The results indicate that the observed fluorescence originates from different types of excited- state species that consist of two or more trans-stilbene units; one of the emissions is attributed to the excited state of a ground-state aggregate while the other is assigned to an excimer that may arise from a 'defect' in the bilayer. The nonexponential nature of the decays is attributed to distributions of environments experienced by the fluorescing species. Electron transfer (ET) reactions between several excited pinacols and carbon tetrachloride in solution have been found to yield products with quantum yields that are higher than unity in the presence of oxygen, suggesting a chain mechanism for product formation. In these systems both the donor and the acceptor undergo bond fragmentation following the initial ET step. The individual steps involved in the proposed mechanism fur these systems have been investigated in part using different steady-state and time-resolved laser spectroscopic techniques. However, it was also necessary to utilize pulse radiolysis in order to confirm the involvement of certain radical intermediates that were not observable by the usual flash photolysis techniques.
- Whitten, David G.,Farahat, Mohammad S.,Gaillard, Elizabeth R.
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- Nitrogen and deuterium kinetic isotope effects on the menshutkin reaction
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Nitrogen and deuterium kinetic isotope effects were measured in the Menshutkin reaction between methyl iodide and a series of para-substituted N,N-dimethylanilines in ethanol. The nitrogen kinetic isotope effect increases for the more electron-donating substituents [0·9989, 1·0032, and 1·0036 for 4-C(O)Me, II and 4-Me, respectively], in agreement with the Hammond postulate. The secondary deuterium isotope effect, however, exhibits the reverse trend (1·045, 0·989, 0·975 per deuterium, for the respective substituents). This discrepancy is rationalized in terms of solvent molecule participation in the transition state.
- Szylhabel-Godala,Madhavan,Rudzinski,O'Leary,Paneth
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- Comparative analysis of crystal structures of E,E-configured para-substituted acetophenone azines with halogen, oxygen, nitrogen and carbon functional groups
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A comparative analysis is presented of the solid state structures of fifteen E,E-configured para-substiutted acetophenone azines with halogen , nitrogen -NMe2 (7), -NH2 (8), -NHCO
- Glaser, Rainer,Chen, Grace Shiahuy,Anthamatten, Mitchell,Barnes, Charles L.
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p. 1449 - 1458
(2007/10/02)
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