- Enhanced catalytic activity of one-dimensional CdS @TiO2 core-shell nanocomposites for selective organic transformations under visible LED irradiation
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In this study, we are interested in the photocatalytic activity under visible LED irradiation of one- dimensional (1D) CdS @TiO2 core–shell nanocomposites (CSNs) prepared through a facile and convenient method. For the synthesis of 1D CdS@TiO2 core/shell structure, titania source (Tetrabutyl titanate) was hydrolyzed by water vapor transmission on the surface of CdS nanowires (NWs) which were prepared via solvothermal method. The characterization of 1D CdS@TiO2 core–shell nanocomposites (CdS@TiO2 CSNs) was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, and UV–Vis diffuse reflectance spectroscopy (DRS). The as-synthesized sample was utilized for the selective reduction of nitro compounds to benzimidazole and anilide, and also the reduction of benzophenones to alcohol under blue LED irradiation. The 1D CdS@TiO2 CSNs exhibited enhanced photoactivity compared with the pure TiO2, CdS nanowires and commercial TiO2-P25. The excellent reusability of the photocatalyst was examined for six runs. The results demonstrated that the prepared sample has the potential to provide a promising visible light-driven photocatalyst for other organic transformations.
- Eskandari, Parvin,Kazemi, Foad,Ramdar, Moosa,Zand, Zahra
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- Ruthenium(II) Complex of a Tridentate Azoaromatic Pincer Ligand and its Use in Catalytic Transfer Hydrogenation of Aldehydes and Ketones with Isopropanol
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In this work, a new Ru(II) complex with the redox-active pincer 2,6-bis(phenylazo)pyridine ligand (L) is reported which acts as a metal-ligand bifunctional catalyst for transfer hydrogenation reactions. The isolated complex [(L)Ru(PMe2Ph)2(CH3CN)](ClO4)2; [1](ClO4)2 is characterized by a host of spectroscopic measurements and X-ray structure determination. It is diamagnetic and single-crystal X-ray structure analysis reveals that [1]2+ adopts a distorted octahedral geometry where L binds Ru center in meridional fashion. The observed elongation in the coordinated azo bond length (1.29 ?) is attributed to the extensive π-back bonding, dπ(RuII)→π*(azo)L. The complex [1](ClO4)2 acts as an efficient catalyst, which brings about catalytic transfer hydrogenation reactions of a broad array of aldehydes and ketones in isopropanol and in inert conditions. The selectivity of the catalyst for aldehyde reduction over the other reducible functional groups such as nitro, nitrile, ester etc was also investigated. Mechanistic studies, examined by suitable control reactions and isotope labelling experiments, indicate synergistic participation of both ligand and metal centres via the formation of a fleeting Ru?H intermediate and hydrogen walking to the coordinated azo function of L.
- Saha, Tanushri,Prasad Rath, Santi,Goswami, Sreebrata
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p. 1455 - 1461
(2021/05/18)
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- Cationic ruthenium(II)–NHC pincer complexes: Synthesis, characterisation and catalytic activity for transfer hydrogenation of ketones
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Cationic ruthenium pincer complexes, [Ru(CNC)(CO)(PPh3)Cl]X (CNC = 2,6-bis(1-methylimidazol-2-ylidene)-pyridine, X = Cl? [1a], PF6? [1b]), [Ru(CNC)(PPh3)2Cl]X (X = Cl? [2a], PF6? [2b]) and [Ru(CNC)(PPh3)2(H)]X (X = Cl? [3a], PF6? [3b]) with triphenylphosphine, CO and halides as coligands have been synthesised and characterised by 1H, 13C, 31P NMR, mass and single-crystal X-ray crystallography. The application of Ru complexes in the transfer hydrogenation of a wide range of ketones with 2-propanol as the hydrogen source is explored. The in situ transformations observed during the synthesis help understand and suggest a plausible mechanism via the hydride complex 3b. All complexes appear to be efficient catalyst precursors for transfer hydrogenation of ketones.
- Yadav, Dibya,Misra, Shilpi,Kumar, Dheeraj,Singh, Suryabhan,Singh, Amrendra K.
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- Synthesis and biological evaluation of 1‐(Diarylmethyl)‐1h‐1,2,4‐triazoles and 1‐(diarylmethyl)‐1h‐imidazoles as a novel class of anti‐mitotic agent for activity in breast cancer
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We report the synthesis and biochemical evaluation of compounds that are designed as hybrids of the microtubule targeting benzophenone phenstatin and the aromatase inhibitor letrozole. A preliminary screening in estrogen receptor (ER)‐positive MCF‐7 breast cancer cells identified 5‐((2H‐1,2,3‐triazol‐1‐yl)(3,4,5‐trimethoxyphenyl)methyl)‐2‐methoxyphenol 24 as a potent antiproliferative compound with an IC50 value of 52 nM in MCF‐7 breast cancer cells (ER+/PR+) and 74 nM in triple‐negative MDA‐MB‐231 breast cancer cells. The compounds demonstrated significant G2/M phase cell cycle arrest and induction of apoptosis in the MCF‐7 cell line, inhibited tubulin polymerisation, and were selective for cancer cells when evaluated in non-tumorigenic MCF‐10A breast cells. The immunofluorescence staining of MCF‐7 cells confirmed that the compounds targeted tubulin and induced multinucleation, which is a recognised sign of mitotic catastrophe. Computational docking studies of compounds 19e, 21l, and 24 in the colchicine binding site of tubulin indicated potential binding conformations for the compounds. Compounds 19e and 21l were also shown to selectively inhibit aromatase. These compounds are promising candidates for development as antiproliferative, aromatase inhibitory, and microtubule‐disrupting agents for breast cancer.
- Ana, Gloria,Kelly, Patrick M.,Malebari, Azizah M.,Noorani, Sara,Nathwani, Seema M.,Twamley, Brendan,Fayne, Darren,O’boyle, Niamh M.,Zisterer, Daniela M.,Pimentel, Elisangela Flavia,Endringer, Denise Coutinho,Meegan, Mary J.
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- Trivalent Rare-Earth Metal Amide Complexes as Catalysts for the Hydrosilylation of Benzophenone Derivatives with HN(SiHMe2)2 by Amine-Exchange Reaction
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The rare-earth metal complexes Ln(L1)[N(SiHMe2)2](thf) (Ln=La, Ce, Y; L1=N,N′′-bis(pentafluorophenyl)diethylenetriamine dianion) were synthesized by treating Ln[N(SiHMe2)2]3(thf)2 with L1H2. The lanthanum and cerium derivatives are active catalysts for the hydrosilylation of benzophenone derivatives with HN(SiHMe2)2. An amine-exchange reaction was revealed as a key step of the catalytic cycle, in which Ln?Si?H β-agostic interactions are proposed to promote insertion of the carbonyl moiety into the Si?H bond.
- Shinohara, Koichi,Tsurugi, Hayato,Anwander, Reiner,Mashima, Kazushi
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supporting information
p. 14130 - 14136
(2020/10/06)
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- Photo-induced phosphorus radical involved semipinacol rearrangement reaction: Highly synthesis of γ-oxo-phosphonates
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Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
- Wang, Chunhai,Huang, Xiaoling,Liu, Xueting,Gao, Suqian,Zhao, Bin,Yang, Shangdong
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supporting information
p. 677 - 680
(2019/08/27)
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- Diaryl hydroxylamines as pan or dual inhibitors of indoleamine 2,3-dioxygenase-1, indoleamine 2,3-dioxygenase-2 and tryptophan dioxygenase
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Tryptophan (Trp) catabolizing enzymes play an important and complex role in the development of cancer. Significant evidence implicates them in a range of inflammatory and immunosuppressive activities. Whereas inhibitors of indoleamine 2,3-dioxygenase-1 (IDO1) have been reported and analyzed in the clinic, fewer inhibitors have been described for tryptophan dioxygenase (TDO) and indoleamine 2,3-dioxygenase-2 (IDO2) which also have been implicated more recently in cancer, inflammation and immune control. Consequently the development of dual or pan inhibitors of these Trp catabolizing enzymes may represent a therapeutically important area of research. This is the first report to describe the development of dual and pan inhibitors of IDO1, TDO and IDO2.
- Winters, Maria,DuHadaway, James B.,Pham, Khoa N.,Lewis-Ballester, Ariel,Badir, Shorouk,Wai, Jenny,Sheikh, Eesha,Yeh, Syun-Ru,Prendergast, George C.,Muller, Alexander J.,Malachowski, William P.
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supporting information
p. 455 - 464
(2018/11/25)
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- Two-component boronic acid catalysis for increased reactivity in challenging Friedel-Crafts alkylations with deactivated benzylic alcohols
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A general and efficient boronic acid catalyzed Friedel-Crafts alkylation of arenes with benzylic alcohols was previously developed for the construction of unsymmetrical diarylmethane products (X. Mo, J. Yakiwchuk, J. Dansereau, J. A. McCubbin and D. G. Hall, J. Am. Chem. Soc., 2015, 137, 9694). Highly electron-deficient benzylic alcohols, however, were ineffective coupling partners due to the increased difficulty of C-O bond ionization. Herein, we report the use of perfluoropinacol as an effective co-catalyst to improve the reactivity of a boronic acid catalyst in the Friedel-Crafts benzylations of electronically deactivated primary and secondary benzylic alcohols. According to spectroscopic studies, it is believed that perfluoropinacol condenses with the arylboronic acid catalyst to form a highly electrophilic and Lewis acidic boronic ester. This in situ formed species enables a more facile ionization of the benzylic alcohols likely through a mode of activation promoted by a Lewis acid assisted hydronium Br?nsted acid generated from the interactions of the transient boronic ester with hexafluoroisopropanol solvent and water.
- Ang, Hwee Ting,Rygus, Jason P. G.,Hall, Dennis G.
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supporting information
p. 6007 - 6014
(2019/06/24)
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- Synthesis and biological evaluation of new N-substituted 4-(arylmethoxy)piperidines as dopamine transporter inhibitors
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The library of new N-substituted 4-(arylmethoxy)piperidines as dopamine transporter inhibitors was designed and synthesized. H-Bond donors in piperidine ring were found to be important for reduced locomotor activity in mice. 4-[Bis(4-fluorophenyl)methoxy]piperidine has IC50 17.0 ± 1.0 nm for dopamine transporter and locomotor activity, which is lower than that for cocaine.
- Lapa, Gennady B.,Lapa, Alla A.
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p. 203 - 205
(2019/04/25)
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- Half-sandwich Ru (II) complexes containing (N, O) Schiff base ligands: Catalysts for base-free transfer hydrogenation of ketones
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Two new half-sandwich Ru (II)(p-cymene) complexes (1 and 2) containing dopamine-based (N, O) Schiff base ligands (L1H and L2H) were synthesized and characterized by FT-IR, UV–Visible and 1H & 13C NMR spectral techniques, and elemental analyses. The spectroscopic and analytical data revealed monobasic bidentate coordination of the ligands with Ru ion. The molecular structures of L1H, L2H and 2 were further confirmed by single crystal X-ray diffraction study. Complexes 1 and 2?have been employed as catalysts in the transfer hydrogenation of ketones using 2-propanol as a hydrogen source at 85?°C under base-free condition. Good to the excellent yield of secondary alcohols, gram scale synthesis, and high TON and TOF made this catalytic system interesting.
- Satheesh,Sathish Kumar, Pushpanathan N.,Kumara, P. Raghavendra,Karvembu, Ramasamy,Hosamani, Amar,Nethaji
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- Preparation method of aromatic nitrile compound or heteroaromatic nitrile compound
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The invention discloses a preparation method of an aromatic nitrile compound or a heteroaromatic nitrile compound. The preparation method comprises: under the protection of an inert gas, in a solvent,under the actions of a nickel catalyst, a ligand, metal zinc and an additive, carrying out a reaction on a cyanation reagent and halogenated aromatic hydrocarbon or halogenated heteroaromatic hydrocarbon. According to the present invention, by using the inexpensive and easily-available nickel catalyst and the ligand, the halogenated aromatic hydrocarbon or halogenated heteroaromatic hydrocarbon,especially the chlorinated aromatic hydrocarbon or chlorinated heteroaromatic hydrocarbon with characteristics of low price, easy obtaining and low reaction activity can mildly and efficiently react with the cyanation reagent with low toxicity to prepare the aromatic nitrile compound or heteroaromatic nitrile compound; and the preparation method has advantages of simple operation, mildness, high efficiency and the like, and further has characteristics of good functional group compatibility, good universality of substrate and the like.
- -
-
Paragraph 0231; 0232
(2018/11/03)
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- Kinetic studies on tetrabutylammonium bromochromate oxidation of some mono-and di-substituted benzhydrols
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The oxidation of 12 mono- and di-substituted benzhydrols (BH) by tetrabutylammonium bromochromate (TBABC) have been studied in aqueous acetic acid medium. Absence of any effect of added acrylonitrile on the reaction discounts the possibility of a one-electron oxidation, leading to the formation of free radicals. The tetrabutylammonium bromochromate oxidation of 12 mono- and di-substituted benzhydrols complies with the isokinetic relationship and Hammett relationship. The overall mechanism is proposed to involve a cyclic concerted symmetrical transition state leading to the product.
- Hemalatha,Asghar, Basim H.,Mansoor, S Sheik
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p. 821 - 826
(2018/03/13)
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- Chemoselective transfer hydrogenation of nitroarenes, ketones and aldehydes using acylthiourea based Ru(II)(p-cymene) complexes as precatalysts
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A new series of Ru(II)(η6-p-cymene) complexes (1–5) was synthesized from pyridine based acylthiourea ligands (L1-L5) and [Ru(η6-p-cymene)Cl2]2. All the ligands and complexes were well characterized by UV-Visible, FT-IR, mass and 1H & 13C NMR spectroscopic techniques. The molecular structures of the ligands (L1, L2, L4 and L5) and complex 1 were confirmed using single crystal X-ray diffraction study. The Ru(II)(η6-p-cymene) complexes (1–5) were proved to be efficient precatalysts for the transfer hydrogenation of carbonyl compounds and nitroarenes in the presence of 2-propanol as a hydrogen donor and KOH as a base. The catalytic transfer hydrogenation reactions were chemoselective towards the nitro group in presence of carbonyl group, which is a rare scenario in homogeneous catalysis. The catalyst was compatible with broad range of substrates which include furfural, quinone and many heterocycles. The catalytic reactions exhibited very high conversions (upto 100%) and excellent yields (upto 99%). Turn Over Number (TON) was found upto 990.
- Sathishkumar, Pushpanathan N.,Raveendran, Neethi,Bhuvanesh, Nattamai S.P.,Karvembu, Ramasamy
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- General and Mild Nickel-Catalyzed Cyanation of Aryl/Heteroaryl Chlorides with Zn(CN)2: Key Roles of DMAP
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A new and general nickel-catalyzed cyanation of hetero(aryl) chlorides using less toxic Zn(CN)2 as the cyanide source has been developed. The reaction relies on the use of inexpensive NiCl2·6H2O/dppf/Zn as the catalytic system and DMAP as the additive, allowing the cyanation to occur under mild reaction conditions (50-80 °C) with wide functional group tolerance. DMAP was found to be crucial for successful transformation, and the reaction likely proceeds via a Ni(0)/Ni(II) catalysis based on mechanistic studies. The method was also successfully extended to aryl bromides and aryl iodides.
- Zhang, Xingjie,Xia, Aiyou,Chen, Haoyi,Liu, Yuanhong
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supporting information
p. 2118 - 2121
(2017/04/27)
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- MeOH or H2O as efficient additive to switch the reactivity of allylSmBr towards carbonyl compounds
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A variety of carbonyl compounds were treated by allylSmBr (allylSmBr) with MeOH as the cosolvent to have further insights on the previously reported reductive coupling of aryl ketones mediated by Sm/alkyl halide/MeOH. The results demonstrate that the real reducing species in Sm/alkyl halide/MeOH system should be allylSmBr, and MeOH has elegantly switched the reactivity of allylSmBr from being nucleophilic to being good reductive coupling reagent. Besides, H2O was also found to be a useful additive to realize the pinacol coupling of aliphatic aldehydes and ketones promoted by allylSmBr.
- Li, Jianyong,Niu, Qingsheng,Li, Shanchan,Sun, Yuehao,Zhou, Qian,Lv, Xin,Wang, Xiaoxia
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supporting information
p. 1250 - 1253
(2017/03/10)
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- Direct allylation of benzyl alcohols, diarylmethanols, and triarylmethanols mediated by XtalFluor-E
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We report the direct allylation of benzyl alcohols, diarylmethanols and triarylmethanols mediated by XtalFluor-E using allyltrimethylsilane. The resulting allylated products are obtained in moderate to high yield.
- Lebleu, Thomas,Paquin, Jean-Fran?ois
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supporting information
p. 442 - 444
(2017/01/10)
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- Discovery, Optimization, and Characterization of Novel Chlorcyclizine Derivatives for the Treatment of Hepatitis C Virus Infection
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Recently, we reported that chlorcyclizine (CCZ, Rac-2), an over-the-counter antihistamine piperazine drug, possesses in vitro and in vivo activity against hepatitis C virus. Here, we describe structure-activity relationship (SAR) efforts that resulted in the optimization of novel chlorcyclizine derivatives as anti-HCV agents. Several compounds exhibited EC50 values below 10 nM against HCV infection, cytotoxicity selectivity indices above 2000, and showed improved in vivo pharmacokinetic properties. The optimized molecules can serve as lead preclinical candidates for the treatment of hepatitis C virus infection and as probes to study hepatitis C virus pathogenesis and host-virus interaction.
- He, Shanshan,Xiao, Jingbo,Dulcey, Andrés E.,Lin, Billy,Rolt, Adam,Hu, Zongyi,Hu, Xin,Wang, Amy Q.,Xu, Xin,Southall, Noel,Ferrer, Marc,Zheng, Wei,Liang, T. Jake,Marugan, Juan J.
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supporting information
p. 841 - 853
(2016/02/23)
-
- Co(III)-Catalyzed Synthesis of Quinazolines via C-H Activation of N-Sulfinylimines and Benzimidates
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C-H activation of arenes has been established as an important strategy for heterocycle synthesis via annulations between arenes and unsaturated coupling partners. However, nitriles failed to act as such a coupling partner. Dioxazolones have been employed as a synthon of nitriles, and subsequent coupling with arenes such as N-sulfinylimines and benzimidates bearing a functionalizable directing group provided facile access to two classes of quinazolines under Co(III)-catalysis.
- Wang, Fen,Wang, He,Wang, Qiang,Yu, Songjie,Li, Xingwei
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p. 1306 - 1309
(2016/04/01)
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- PIPERIDINE AND PIPERAZINE DERIVATIVES AND THEIR USE IN TREATING VIRAL INFECTIONS AND CANCER
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Disclosed are compounds of formula (I) (formula I),as antiviral agents, antineoplastic agents, pharmaceutical compositions comprising such compounds, and a method of use of these compounds, wherein X and Y are independently CH or N, o is 0, 1 or 2, and E is absent or is (CR13 R14 )m, NH, or S, F is absent or is (CR15 R16 )n, C=O, or -SO2 -, G is absent or is (CR17 CR18 )r, H is absent or is C=O, or -SO2 - and R1, Ar1, Ar2 are as defined in the specification. These compounds are antiviral agents and are contemplated in the treatment of viral infections, for example, hepatitis C, or are antineoplastic agents.
- -
-
Paragraph 0310; 0311
(2015/06/11)
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- UV light-mediated difunctionalization of alkenes through aroyl radical addition/1,4-/1,2-Aryl shift cascade reactions
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UV light-mediated difunctionalization of alkenes through an aroyl radical addition/1,4-/1,2-aryl shift has been described. The resulted aroyl radical from a photocleavage reaction added to acrylamide compounds followed by cyclization led to the formation of oxindoles, whereas the addition to cinnamic amides aroused a unique 1,4-aryl shift reaction. Furthermore, the difunctionalization of alkenes of prop-2-en-1-ols was also achieved through aroyl radical addition and a sequential 1,2-aryl shift cascade reaction.
- Zheng, Lewei,Huang, Hongli,Yang, Chao,Xia, Wujiong
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supporting information
p. 1034 - 1037
(2015/03/30)
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- Development of small-molecule probes that selectively kill cells induced to express mutant RAS
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Synthetic lethal screening is a chemical biology approach to identify small molecules that selectively kill oncogene-expressing cell lines with the goal of identifying pathways that provide specific targets against cancer cells. We performed a high-throughput screen of 303,282 compounds from the National Institutes of Health-Molecular Libraries Small Molecule Repository (NIH-MLSMR) against immortalized BJ fibroblasts expressing HRASG12V followed by a counterscreen of lethal compounds in a series of isogenic cells lacking the HRASG12V oncogene. This effort led to the identification of two novel molecular probes (PubChem CID 3689413, ML162 and CID 49766530, ML210) with nanomolar potencies and 4-23-fold selectivities, which can potentially be used for identifying oncogene-specific pathways and targets in cancer cells.
- We?wer, Michel,Bittker, Joshua A.,Lewis, Timothy A.,Shimada, Kenichi,Yang, Wan Seok,MacPherson, Lawrence,Dandapani, Sivaraman,Palmer, Michelle,Stockwell, Brent R.,Schreiber, Stuart L.,Munoz, Benito
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supporting information; experimental part
p. 1822 - 1826
(2012/04/04)
-
- Isomorphous crystals by chloro-methyl exchange in polymorphic fuchsones
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The X-ray crystal structures of four fuchsone derivatives in which a chloro group is replaced by methyl were analyzed to understand isostructurality upon Cl-Me exchange in a polymorphic family of molecules. The four methyl groups in tetramethyl fuchsone (TMF, 2,6-dimethyl and α,α-di-p-tolyl) were substituted with chlorine pairwise to give dichloro dimethyl (CMF, 2,6-dichloro and α,α-di-p-tolyl), dimethyl dichloro (MCF, 2,6-dimethyl and α,α-di-p-chlorophenyl), and tetrachloro derivatives (TCF, 2,6-dichloro and α,α-di-p-chlorophenyl). The first three compounds are polymorphic, whereas TCF afforded one crystal modification only. TMF, CMF, and MCF are isostructural and isomorphous crystals in the category of polymorphs, solid solutions, and solvates. The first case of color polymorphism in fuchsone dyes is reported for CMF dimorphs. The formation of solid solution is one of the most stringent tests of isostructutality, which was observed for TMF, CMF, and MCF but not for TCF. Crystal packing in TCF is dominated by short Cl·Cl interactions, and consequently this crystal structure is different from the first three members which are largely a result of space filling. Crystal structures were analyzed using the XPac program to calculate the dissimilarity index of supramolecular constructs and Hirshfeld fingerprint plots to quantify the contribution of Cl·Cl interactions. Isostructurality was observed up to 50% exchange of Cl with Me, but after that point the structure deviates to another packing motif.
- Nath, Naba K.,Nangia, Ashwini
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p. 5411 - 5425
(2013/01/15)
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- One-pot synthesis of 1-iodoalkynes and trisubstituted alkenes from benzylic and allylic bromides
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1-Iodoalkynes are formed in moderate to high yields from readily accessible benzylic and allylic alkyl bromides by a one-pot homologation/double elimination procedure with iodoform (CHI3). The developed conditions include facile purification and avoid the use of an excess of triphenylphosphine (PPh3), as described in classical Corey-Fuchs iodoalkynylation conditions. Replacing CHI3 with CHI2Cl allows the isolation of the corresponding gem-(Z)-chloro-(E)-iodoalkene in good yield and stereoselectivity. Moreover, the use of benzhydryl bromides as nucleophiles enables the synthesis of trisubstituted alkenes under similar reaction conditions.
- Pelletier, Guillaume,Lie, Sharon,Mousseau, James J.,Charette, Andre B.
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supporting information
p. 5464 - 5467,4
(2020/10/15)
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- The arylation of aldehydes with arylboronic acids using metal-organic framework Ni(HBTC)BPY as an efficient heterogeneous catalyst
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A highly crystalline porous Ni(HBTC)BPY was synthesized from the reaction of 1,3,5-benzenetricarboxylic acid, nickel nitrate hexahydrate, and 4,4′-bipyridine by a solvothermal method. Physical characterizations of the solid catalyst were achieved by using several techniques, including X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), atomic absorption spectrophotometry (AAS), and nitrogen physisorption measurements. The Ni(HBTC)BPY exhibited high catalytic activity in the arylation of aldehydes with arylboronic acids to form diarylmethanols. The catalyst could be separated from the reaction mixture by simple filtration or centrifugation, and could be reused without a significant degradation in catalytic activity. No contribution from homogeneous catalysis of active species leaching into the liquid phase was detected.
- Phan, Nam T.S.,Nguyen, Tung T.,Ta, Anh H.
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- N-heterocyclic carbene-catalyzed cross-coupling of aromatic aldehydes with activated alkyl halides
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N-Heterocyclic carbene-catalyzed umpolung of aldehydes followed by their interception with diarylbromomethanes has been reported. This conceptually novel transition-metal-free cross-coupling of aldehydes with alkyl halides works well at low catalyst loadings and under mild reaction conditions leading to the formation of diaryl acetophenone derivatives in good yields. In addition, α-halo ketones and esters can also be used as aldehyde reaction partners.
- Padmanaban, Mohan,Biju, Akkattu T.,Glorius, Frank
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supporting information; experimental part
p. 98 - 101
(2011/03/19)
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- Synthesis and anticonvulsant activity of some cinnamylpiperazine derivatives
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A series of cinnamylpiperazine derivatives was synthesized using different benzophenone as starting material. The structures of the compounds were proved by their IR, 1H-NMR spectroscopic data and mass spectra data. The anticonvulsant activities of these compounds were evaluated with maximal electroshock (MES) test and rotarod test with intraperitoneal injection on KunMing mice. Among all the flunarizine analogues, no one exhibited better anticonvulsant activity than flunarizine. Flunarizine (4i) exhibited anticonvulsant activity with ED50 of 38.1 mg/kg, TD50 of 164.3 mg/kg and PI of 4.3 through administration intraperitoneal, and with ED50 of 56.8 mg/kg, TD50 of 456.3 mg/kg and PI of 8.0 through oral administration.
- Hu, Chuan,Sun, Zhi-Gang,Wei, Cheng-Xi,Quan, Zhe-Shan
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scheme or table
p. 661 - 664
(2011/11/29)
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- Enantioselective catalytic α-alkylation of aldehydes via an S N1 pathway
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Primary aminothiourea derivatives are shown to catalyze enantioselective alkylation of α-arylpriopionaldehdyes with diarylbromomethane. Evidence for a stepwise, S N1 mechanism in the substitution reaction induced by anion binding to the catalyst is provided by catalyst structure-activity studies, kinetic isotope effects, linear free-energy relationship studies, and competition experiments.
- Brown, Adam R.,Kuo, Wen-Hsin,Jacobsen, Eric N.
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supporting information; experimental part
p. 9286 - 9288
(2010/11/03)
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- Suppression of common-ion return by amines: A method to measure rates of fast SN1 reactions
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(Chemical Equation Presented) Rate constants for solvolyses of benzhydryl chlorides, which take place on the 10 ms to minute time scale, have been determined in aqueous acetone and acetonitrile by conductometry, using conventional conductometers as well as stopped-flow techniques. Secondary and tertiary amines were used to suppress ion recombination (common-ion return) thus giving access to the ionization rate constants k1. The observed common-ion rate depressions can be rationalized by the correlation equation for electrophile-nucleophile combinations, log k(20 °C) = s(E + N), where electrophiles (here: carbocations) are characterized by the parameter Eand nucleophiles (here: chloride anions and solvents) are characterized by N and s. 2009 American Chemical Society.
- Streidl, Nicolas,Antipova, Anna,Mayr, Herbert
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supporting information; experimental part
p. 7328 - 7334
(2010/01/16)
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- CATIONIC TRANSITION-METAL ARENE CATALYSTS
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Disclosed are cationic ruthenium arene complexes of Formula (I): [Ru(D-Z1-NHR1)(Ar)(LB)n]r+[Y-]r wherein Ar is optionally substituted aryl, D-Z1-NHR1 is a coordinated bidentate ligand wherein D, Z1, R1 and R2 are as defined herein, and where R1 and Ar, or R2 and Ar may be linked together, n is 0 or 1, r is 1 or 2, LB is a neutral Lewis base, and Y is a non-coordinating anion. The complexes are active catalysts for reduction reactions, including the transfer-hydrogenation of carbon-oxygen (C=O) and carbon-nitrogen (C=N) double bonds.
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Page/Page column 29; 37
(2009/12/05)
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- Dual functionalization of allene: facile construction of heteropolycycles mediated by Bronsted acid
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A facile construction of a heteropolycyclic framework is developed by exploiting the dual functionalization of allene. On treatment of phenethyl alcohol or amine bearing a terminal allene with the Bronsted acid, two consecutive reactions to allene, nucleophilic addition of heteroatom and the Friedel-Crafts reaction, occurred to give 2-oxa-or azabicyclo[2.2.2]octane skeleton. Copyright
- Mori, Keiji,Sueoka, Shosaku,Akiyama, Takahiko
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supporting information; experimental part
p. 628 - 629
(2011/04/22)
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- Convenient synthesis of structurally novel 1,3-disubstituted azetidine derivatives
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A convenient synthesis of structurally novel 1,3-disubstituted azetidine derivatives is described. The approach involves condensation of an azetidine building block with sulfonylated carbamic acid methyl ester, subsequently followed by quenching the imidoyl chloride with amines. Different derivatives were prepared by substituting benzhydrol as well as benzenesulfonamide as part of the core structure. Copyright Taylor & Francis Group, LLC.
- Kharul, Rajendra K.,Goswami, Amitgiri,Gite, Archana,Godha, Atul K.,Jain, Mukul,Patel, Pankaj R.
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p. 1703 - 1717
(2008/09/20)
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- Exploring the reactivity of C(sp3)-cyclometalated Ir III compounds in hydrogen transfer reactions
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The manuscript describes the synthesis and full characterization of a new PC(sp3)P-based cyclometalated IrIII complex that manifests an exceptional thermal stability, as well as outstanding reactivity in hydrogen transfer reactions. The described compound represents the first example of a new family of stable C-(sp3)-metalated compounds.
- Azerraf, Clarite,Gelman, Dmitri
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experimental part
p. 10364 - 10368
(2009/12/05)
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- Design, synthesis and biological evaluation of piperazine analogues as CB1 cannabinoid receptor ligands
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After the CB1 receptor antagonist SR141716 (rimonabant) was previously reported to modulate food intake, CB1 antagonism has been considered as a new therapeutic target for the treatment of obesity. Several series of urea, carbamate, amide, sulfonamide and oxalamide derivatives based on 1-benzhydrylpiperazine scaffold were synthesized and tested for CB1 receptor binding affinity. The SAR studies to optimize the CB1 binding affinity led to the potent urea derivatives. After the additional SAR studies to optimize the substituents of diphenyl rings, the combination of 2-chlorophenyl and 4-chlorophenyl turned out to be the most potent scaffold. The CB2 binding affinity assay as well as functional assay was also conducted on these compounds. Herein we wish to introduce several novel CB1 antagonists with IC50 values less than 100 nM for the CB1 receptor binding.
- Song, Kwang-Seop,Lee, Sung-Han,Chun, Hyun Ji,Kim, Jong Yup,Jung, Myung Eun,Ahn, Kwangwoo,Kim, Soo-Un,Kim, Jeongmin,Lee, Jinhwa
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p. 4035 - 4051
(2008/09/21)
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- Bronsted acid-catalyzed benzylation of 1,3-dicarbonyl derivatives
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The direct alkylation of 1,3-dicarbonyl compounds with benzylic alcohols is shown to be efficiently catalyzed by simple Bronsted acids such as triflic acid (TfOH) and p-toluenesulfonic acid (PTS) to give rise to monoalkylated dicarbonyl derivatives in high yields. In the absence of the nucleophile, substituted alkenes, generated through a formal dimerization reaction, are obtained. The reactions are carried out in air using undried solvents, with water being the only side product of the process.
- Sanz, Roberto,Miguel, Delia,Martinez, Alberto,Alvarez-Gutierrez, Julia M.,Rodriguez, Felix
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p. 2027 - 2030
(2008/02/02)
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- The ritter reaction under truly catalytic bronsted acid conditions
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Simple organic acids like 2,4-dinitrobenzenesulfonic acid (DNBSA) catalyze the Ritter reaction of secondary benzylic alcohols giving rise to the corresponding N-benzylacetamides in usually high yields. Reactions can be conducted without exclusion of oxygen and without the need of dry solvents. With tertiary α,α-dimethylbenzylic alcohols a different pathway involving a formal dimerization reaction takes place under the acid-catalytic conditions used. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Sanz, Roberto,Martinez, Alberto,Guilarte, Veronica,Alvarez-Gutierrez, Julia M.,Rodriguez, Felix
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p. 4642 - 4645
(2008/03/12)
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- METHOD AND INTERMEDIATES FOR THE PREPARATION OF DERIVATIVES OF N (1-BENZHYDRYLAZETIDIN-3-YL)-N-PHENYLMETHYLSULFONAMIDE
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The invention relates to a novel method for the synthesis of N-{1-[bis(4-chlorophenyl)methyl]azetidin-3-yl}-N-(3,5-difluorophenyl)methylsulfonamide.
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Page/Page column 5
(2008/06/13)
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- RUTHENIUM COMPLEXES, THEIR PREPARATION AND USE AS CATALYSTS
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The patent describes a novel class of ruthenium(II) complexes, containing a cyclometallated phosphine, which have been shown to be effective catalysts of the reduction reaction of ketones to alcohols through transfer hydrogenation. With such ruthenium complexes, using 2-propanol as a source of hydrogen, it is possible to obtain the corresponding alcohol starting from linear and cyclic diaryl, alkylaryl and dialkyl ketones, rapidly and with high yield. Using such complexes and starting from ketone compounds, the process for the production of various types of alcohols, which are important intermediates for the pharmaceutical, agrochemical and the fine chemical industries in general, is particularly convenient.
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Page/Page column 15
(2010/02/11)
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- The synthesis and biological evaluation of dopamine transporter inhibiting activity of substituted diphenylmethoxypiperidines
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The synthesis of potent 4-aryl methoxypiperidinol inhibitors of the dopamine transporter is described. Symmetrical para substituents of the benzene rings are important for high potency in binding to the dopamine transporter. 4-[Bis(4-fluorophenyl) methoxy]-1-methylpiperidine has an IC50 of 22.1 ± 5.73 nM and increases locomotor activity in mice.
- Lapa, Gennady B.,Byrd, Gary D.,Lapa, Alla A.,Budygin, Evgeny A.,Childers, Steven R.,Jones, Sara R.,Harp, Jill J.
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p. 4915 - 4918
(2007/10/03)
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- Design, synthesis, and biological evaluation of novel T-Type calcium channel antagonists
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This paper describes the synthesis of several novel T-type calcium channel antagonists that inhibit calcium influx into the cell, which in turn regulates unknown aspects of the cell cycle pathway that are responsible for cellular proliferation. A library of compounds was synthesized anda brief structure activity relationship will be described. From these studies we have identified a compound (1) that displays anti-proliferative activity in the low micromolar range across a variety of cancer cell lines.
- McCalmont, William F.,Heady, Tiffany N.,Patterson, Jaclyn R.,Lindenmuth, Michael A.,Haverstick, Doris M.,Gray, Lloyd S.,Macdonald, Timothy L.
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p. 3691 - 3695
(2007/10/03)
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- Cyclometalated ruthenium(II) complexes as highly active transfer hydrogenation catalysts
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Quantitative conversion: Reaction of the 14-electron complex [RuCl 2{(2,6-Me2C6H3)PPh2} 2] with CH2O in the presence of NEt3 gave a five-coordinate cyclometalated complex with a δ-agostic interaction of one ortho-methyl group (see X-ray crystal structure), Displacement of one phosphane group with 2-(amino-methyl)pyridine gave a highly active catalyst for the quantitative conversion of ketones into alcohols.
- Baratta, Walter,Da Ros, Paolo,Del Zotto, Alessandro,Sechi, Alessandra,Zangrando, Ennio,Rigo, Pierluigi
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p. 3584 - 3588
(2007/10/03)
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- SN1 reactions with inverse rate profiles
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Carbocations may accumulate during solvolysis reactions! The fact that fast ionization followed by slow trapping of the carbocation R+ is a characteristic pattern of many solvolysis reactions requires that the generally accepted energy profiles of these reactions be revised.
- Denegri, Bernard,Minegishi, Shinya,Kronja, Olga,Mayr, Herbert
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p. 2302 - 2305
(2007/10/03)
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- Pinacol Formation and Reduction of Aromatic Carbonyls with Magnesium-Methanol at Ambient Temperature
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A simple and inexpensive procedure for the pinacol formation of aromatic aldehydes and reduction of aromatic ketones to the corresponding alcohols with magnesium in dry methanol at ambient temperature is reported. The pinacol formation and reduction are proposed to be proceeding by SET from magnesium.
- Khurana, Jitender M.,Bansal, Geeti,Kukreja, Gagan,Pandey, Ravi R.
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p. 1365 - 1371
(2007/10/03)
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- Photoreduction of benzophenones by amines in room-temperature ionic liquids
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(equation presented) The amine-mediated photoreduction of benzophenones in room temperature ionic liquids was investigated. Unlike the analogous reaction in organic solvents, the photoreduction produces mainly the corresponding benzhydrol in most cases. Because the reaction consumes only 1 equiv of amine and the solvent can be easily recycled, the photoreduction allows a very clean method for the conversion of benzophenones to benzhydrols.
- Reynolds, John L.,Erdner, Kimberly R.,Jones, Paul B.
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p. 917 - 919
(2007/10/03)
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- Rapid reduction of carbonyls with nickel boride at ambient utemperature
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Carbonyl compounds have been reported to undergo rapid reduction with nickel boride generated in situ from anhyd. nickel chloride and sodium borohydride in THF at ambient temperature to the corresponding alcohols in high yields.
- Khurana,Chauhan
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p. 3485 - 3489
(2007/10/03)
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- Ultrasound-promoted samarium/ammonium chloride mediated reductive coupling of aromatic ketones
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Ultrasound-promoted samarium/ammonium chloride mediated reductive coupling of aromatic ketones was investigated.
- Basu,Becker,Banik
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p. 406 - 407
(2007/10/03)
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- DDT, DDD, and DDE dechlorination by zero-valent iron
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Traditionally, destruction of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] for environmental remediation required high-energy processes such as incineration. Here, the capability of powdered zero-valent iron to dechlorinate DDT and related compound
- Sayles, Gregory D.,You, Guanrong,Wang, Maoxiu,Kupferle, Margaret J.
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p. 3448 - 3454
(2007/10/03)
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- Hydrodehalogenation of Polyhalogenated Aromatics under Multiphase Conditions with H2 and Metal Catalyst: Kinetics and Selectivity
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Aryl halides have been catalytically hydrodehalogenated by bubbling H2 at atmospheric pressure into a biphasic system constituted by an organic solvent and an aqueous solution (aq., KOH 50percent), in the presence of a metal catalyst (Pd/C or Ranay-Ni) and a quaternary onium salt as a phase-transfer (PT) catalyst.Under such new conditions, the hydrodehalogenation of aromatic halides, even of sterically hindered ones, proceeds quickly at low temperatures (20-50 deg C) and affords the corresponding non-halogenated hydrocarbons in substantially quantitative yields.The addition of a quaternary onium salt to the multiphase system may induce remarkable effects both in the enhancement of the reduction rate and in the regio- and chemo-selectivity of the reaction.For instance, when Aliquat 336 (tricaprylmethylammonium chloride) is used, the isomeric chloroethylbenzenes react 50 times faster, para-dichlorobenzene is reduced slower than the ortho isomer, and halogenated aromatic ketones can be effectively dehalogenated, without any reduction of the carbonyl group.Under the same reaction conditions, the addition of an onium salt is required for the Raney-Ni catalyst to become effective as a hydrodehalogenation catalyst.
- Marques, Carlos Alberto,Selva, Maurizio,Tundo, Pietro
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p. 317 - 328
(2007/10/03)
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- Surface modification of CdS quantum dots with fluorinated thiophenol
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CdS nanocrystallites prepared by capping with pentafluorothiophenol, 2,3,5,6-tetrafluorothiophenol or 4-fluorothiophenol are characterized as quantum dots by TEM, FTIR, NMR, UV-VIS and fluorescence spectroscopy. The crystalline size tends to increase with an increase in the number of fluorine atoms in the capping molecules while maintaining high solubility in organic solvents, with solubility in alcohols depending on the number of fluorine atoms in the capping molecules. Pentafluorophenyl-capped CdS nanocrystallites have the highest solubilities in alcohols, and exhibit quantum dot photocatalysis in methanol, leading to the efficient two-electron transfer photoreduction under visible-light irradiation.
- Hosokawa, Hiroji,Ogata, Tomoyuki,Wada, Yuji,Murakoshi, Kei,Sakata, Takao,Mori, Hirotaro,Yanagida, Shozo
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p. 4575 - 4580
(2007/10/03)
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- 2-benzoylbenzoic acid: A photolabile mask for alcohols and thiols
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Photolysis of 2-benzoylbenzoate esters of primary and secondary alcohols 1 in the presence of a hydrogen donor (2-isopropanol) or an electron donor (primary amines) produces the corresponding alcohol in high yield. The fate of the benzoate is dependent on the conditions used for the photoreaction. In 2-propanol, the ketyl radical that derives from photoreduction dimerizes, to afford the benzpinacol product 3,3"-diphenylbiphthalidyl, 5. In the presence of amines the product is 3-phenylphthalide, 6, a benzhydrol derivative which is the result of simple reduction of the ketone followed by lactonization. While the photoproduct of the benzoate - 2-propanol reaction results from anticipated free radical chemistry, the amine-promoted reaction appears to result from a second, "dark", electron transfer process. We conclude that 2-benzoylbenzoic acid is an effective photolabile protecting group for primary and secondary alcohols, and preliminary studies indicate that thiols can be protected in an analogous way. Studies on the effect of benzophenone substituents and reaction solvent on the benzhydrol:benzpinacol product ratio provide mechanistic insight into the process.
- Jones, Paul B.,Pollastri, Michael P.,Porter, Ned A.
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p. 9455 - 9461
(2007/10/03)
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- Pinacolization and reduction of aromatic carbonyls with aluminium-KOH
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A simple and rapid procedure for the pinacolization of aromatic aldehydes and reduction of hindered ketones with inexpensive aluminium and KOH in methanol at ambient temperature is reported. The pinacolization and reduction are proposed to be proceeding via single electron transfer from aluminium. Copyright 1996 by the Royal Society of Chemistry.
- Khurana, Jitender M.,Sehgal, Arti,Gogia, Amita,Manian, Aparna,Maikap, Golak C.
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p. 2213 - 2215
(2007/10/03)
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