- Investigation of the structure and opto-electronic properties of substituted 2,2′-bithiophenes as π-building blocks: A joint experimental and theoretical study
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We present the design and the synthesis of substituted 2,2′-bithiophene derivatives to be used as π-conjugated bridges in donor-π-acceptor molecules for dye sensitized solar cells. Using a combined theoretical and experimental approach, the photophysical and electrochemical properties of these linkers are also presented. Finally, we show that the photophysical properties (absorption/emission) of these molecules are preserved when doped in host matrices.
- Andicsová-Eckstein,Tokár,Kozma,Tokárová
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Read Online
- Novel preparation of tiaprofenic acid
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A new synthesis of the nonsteroidal anti-inflammatory drug tiaprofenic acid starting from thiophene is described. The sequence involves five steps, and the acylation with benzoyl chloride was catalysed by zinc oxide under solventfree conditions at room temperature. This method uses a much cheaper starting material and has a higher total yield (78.4%) than other methods. It is suitable for industrial production.
- Zhang, Shuguang,Huang, Shuang,Feng, Chengliang,Cai, Jin,Chen, Junqing,Ji, Min
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Read Online
- KOtBu/DMSO Catalytic System for Isomerization of Allylic Alcohols to Ketones
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The isomerization of allylic alcohols is an important reaction because it can afford carbonyl compounds in an atom-economical manner. Although base-catalyzed methods are more desirable than those using transition-metal catalysts from both the economic and environmental points of view, these methods have several drawbacks, such as narrow substrate scope and high catalyst loading. This paper reports the development of an efficient KOtBu/DMSO catalytic system suitable for the isomerization of a broad range of allylic alcohols with good yields, to which previously reported systems could not be applied. This catalytic system was successfully applied to a tandem allylic isomerization/electrophilic trapping reaction, thereby highlighting its synthetic utility.
- Sai, Masahiro
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- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
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An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
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supporting information
p. 7445 - 7449
(2021/10/02)
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- Photoactive electron donor-acceptor complex platform for Ni-mediated C(sp3)-C(sp2) bond formation
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A dual photochemical/nickel-mediated decarboxylative strategy for the assembly of C(sp3)-C(sp2) linkages is disclosed. Under light irradiation at 390 nm, commercially available and inexpensive Hantzsch ester (HE) functions as a potent organic photoreductant to deliver catalytically active Ni(0) species through single-electron transfer (SET) manifolds. As part of its dual role, the Hantzsch ester effects a decarboxylative-based radical generation through electron donor-acceptor (EDA) complex activation. This homogeneous, net-reductive platform bypasses the need for exogenous photocatalysts, stoichiometric metal reductants, and additives. Under this cross-electrophile paradigm, the coupling of diverse C(sp3)-centered radical architectures (including primary, secondary, stabilized benzylic, α-oxy, and α-amino systems) with (hetero)aryl bromides has been accomplished. The protocol proceeds under mild reaction conditions in the presence of sensitive functional groups and pharmaceutically relevant cores.
- Kammer, Lisa Marie,Badir, Shorouk O.,Hu, Ren-Ming,Molander, Gary A.
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p. 5450 - 5457
(2021/05/05)
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- Characterization of initial reaction intermediates in heated model systems of glucose, glutathione, and aliphatic aldehydes
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To understand the effect of lipid degradation on Maillard formation of meaty flavors, initial reaction intermediates in model systems of glucose–glutathione with hexanal, (E)-2-heptenal, or (E,E)-2,4-decadienal were identified by HPLC–MS and by NMR. Besides Amadori compounds, hemiacetals and thiazolidines via addition of sulfhydryl to carbonyl or to the conjugated olefinic bond were found. Concentrations of all intermediates increased with reaction time while degradation of the intermediates with a glutathione moiety helped formation of thiazolidines with cysteinylglycine. The unsaturated aldehydes (E)-2-heptenal and (E,E)-2,4-decadienal exhibited high reactivity against glucose for glutathione, yielding higher levels of intermediate compounds than from glucose. Heating prepared intermediates reversibly released the original aldehydes, which caused various compounds formed by retro-aldol, oxidation, etc. to react with H2S and NH3. Among them, formation pathways including 3-nonen-2-one, 2-hexanoylfuran, and six dialkylthiophenes (e.g., 2-ethyl-5-(1-methylbutyl)thiophene) were proposed for the first time.
- Wang, Tianze,Zhen, Dawei,Tan, Jia,Xie, Jianchun,Cheng, Jie,Zhao, Jian
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- Manganese PNP-pincer catalyzed isomerization of allylic/homo-allylic alcohols to ketones-activity, selectivity, efficiency
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We report the first manganese catalyzed isomerization of allylic alcohols to produce the corresponding carbonyl compounds. The ligand plays a decisive role in the efficiency of this reaction. Very high conversions could be obtained using a solvent-free reaction system. A detailed DFT study reveals a self-dehydrogenation/hydrogenation reaction mechanism which was verified by the isolation of the α,β-unsaturated ketone as intermediate and a deuterium labeling experiment. It also provided a rationale for the observed selectivity and the higher efficiency of phenyl over isopropyl substitution.
- Xia, Tian,Spiegelberg, Brian,Wei, Zhihong,Jiao, Haijun,Tin, Sergey,Hinze, Sandra,De Vries, Johannes G.
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p. 6327 - 6334
(2019/11/20)
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- Additive-Free Isomerization of Allylic Alcohols to Ketones with a Cobalt PNP Pincer Catalyst
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Catalytic isomerization of allylic alcohols in ethanol as a green solvent was achieved by using air and moisture stable cobalt (II) complexes in the absence of any additives. Under mild conditions, the cobalt PNP pincer complex substituted with phenyl groups on the phosphorus atoms appeared to be the most active. High rates were obtained at 120 °C, even though the addition of one equivalent of base increases the speed of the reaction drastically. Although some evidence was obtained supporting a dehydrogenation–hydrogenation mechanism, it was proven that this is not the major mechanism. Instead, the cobalt hydride complex formed by dehydrogenation of ethanol is capable of double-bond isomerization through alkene insertion–elimination.
- Spiegelberg, Brian,Dell'Acqua, Andrea,Xia, Tian,Spannenberg, Anke,Tin, Sergey,Hinze, Sandra,de Vries, Johannes G.
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supporting information
p. 7820 - 7825
(2019/05/22)
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- Isomerization of Allylic Alcohols to Ketones Catalyzed by Well-Defined Iron PNP Pincer Catalysts
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[Fe(PNP)(CO)HCl] (PNP=di-(2-diisopropylphosphanyl-ethyl)amine), activated in situ with KOtBu, is a highly active catalyst for the isomerization of allylic alcohols to ketones without an external hydrogen supply. High reaction rates were obtained at 80 °C, but the catalyst is also sufficiently active at room temperature with most substrates. The reaction follows a self-hydrogen-borrowing mechanism, as verified by DFT calculations. An alternative isomerization through alkene insertion and β-hydride elimination could be excluded on the basis of a much higher barrier. In alcoholic solvents, the ketone product is further reduced to the saturated alcohol.
- Xia, Tian,Wei, Zhihong,Spiegelberg, Brian,Jiao, Haijun,Hinze, Sandra,de Vries, Johannes G.
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supporting information
p. 4043 - 4049
(2018/01/27)
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- 2-Methyl-3-aryloxy-3-heteroarylpropylamine compounds and application
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The invention relates to 2-methyl-3-aryloxy-3-heteroarylpropylamine compounds and their pharmaceutical application. It is discovered via experiments that these compounds are KCNQ2/3 channel blockers, having good anti-depression activity, capable of improving cognitive function and having low acute toxicity.
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Paragraph 0059; 0060
(2017/06/28)
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- Magnesium salt promoted tandem nucleophilic addition-Oppenauer oxidation of aldehydes with organozinc reagents
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A magnesium salt promoted synthesis of ketones via tandem nucleophilic addition-Oppenauer oxidation of aldehydes using organozinc chemistry was demonstrated. Magnesium salts concomitantly generated via magnesium metal mediated organohalide zincation exhibit high efficacy for nucleophilic addition of organozinc reagents to aromatic aldehydes and thereafter Oppenauer oxidation whereby ketones are formed in high to excellent yields.
- Fu, Ying,Zhao, Xing Ling,Hügel, Hulmet,Huang, Danfeng,Du, Zhengyin,Wang, Kehu,Hu, Yulai
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supporting information
p. 9720 - 9724
(2016/10/31)
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- Direct conversion of allyl arenes to aryl ethylketones via a TBHP-mediated palladium-catalyzed tandem isomerization-Wacker oxidation of terminal alkenes
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A TBHP-mediated palladium-catalyzed tandem isomerization-Wacker oxidation of terminal alkenes was developed. This methodology provides a new efficient and simple route for conversion of a range of allyl arenes directly into aryl ethylketones in good yields with high chemoselectivity.
- Zhao, Jinwu,Liu, Li,Xiang, Shijian,Liu, Qiang,Chen, Huoji
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supporting information
p. 5613 - 5616
(2015/05/27)
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- Synthesis of enantiopure glycidol derivatives via a one-pot two-step enzymatic cascade
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Styrene monooxygenase (SMO) can catalyze the kinetic resolution of secondary allylic alcohols to provide enantiopure glycidol derivatives. To overcome the low theoretical yield of kinetic resolution, we designed a one-pot two-step enzymatic cascade using prochiral α,β-unsaturated ketones as the substrates. An S-specific ketoreductase ChKRED03 was screened for the efficient bioreduction of the substrates to provide (S)-allylic alcohols, which underwent SMO-catalyzed epoxidation to achieve glycidol derivatives with contiguous stereogenic centers. Excellent enantioselectivity (ee > 99%) and diastereoselectivity (de > 99%) were achieved for the majority of the substrates, and product yields reached up to >99%. This journal is
- Liu, Yu-Chang,Liu, Yan,Wu, Zhong-Liu
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p. 2146 - 2152
(2015/03/05)
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- ZnCl2-promoted asymmetric hydrogenation of β-secondary-amino ketones catalyzed by a P-chiral rh-bisphosphine complex
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A new catalytic system has been developed for the asymmetric hydrogenation of β-secondary-amino ketones using a highly efficient P-chiral bisphosphine-rhodium complex in combination with ZnCl2 as the activator of the catalyst. The chiral γ-secondary-amino alcohols were obtained in 90-94% yields, 90-99% enantioselectivities, and with high turnover numbers (up to 2000 S/C; S/C = substrate/catalyst ratio). A mechanism for the promoting effect of ZnCl2 on the catalytic system has been proposed on the basis of NMR spectroscopy and HRMS studies. This method was successfully applied to the asymmetric syntheses of three important drugs, (S)-duloxetine, (R)-fluoxetine, and (R)-atomoxetine, in high yields and with excellent enantioselectivities.
- Hu, Qiupeng,Zhang, Zhenfeng,Liu, Yangang,Imamoto, Tsuneo,Zhang, Wanbin
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supporting information
p. 2260 - 2264
(2015/02/19)
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- DIARYL[A, G]QUINOLIZIDINE COMPOUND, PREPARATION METHOD THEREFOR, PHARMACEUTICAL COMPOSITION, AND USES THEREOF
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The present invention relates to a diarylo[a,g]quinolizidine compound of formula (I), enantiomer, diastereoisomer, racemate, mixture, pharmaceutically acceptable salt, crystalline hydrate or solvate thereof; the preparation method thereof, and uses thereof in preparing an experimental model drugs related to dopamine receptors and 5-HT receptors or a medicament for treating or preventing a disease related to dopamine receptors and 5-HT receptors.
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Paragraph 0091; 0092
(2015/03/28)
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- DIARYL[A, G]QUINOLIZIDINE COMPOUND, PREPARATION METHOD THEREFOR, PHARMACEUTICAL COMPOSITION, AND USES THEREOF
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The present invention relates to a diarylo[a,g]quinolizidine compound of formula (I), enantiomer, diastereoisomer, racemate, mixture, pharmaceutically acceptable salt, crystalline hydrate or solvate thereof; the preparation method thereof, and uses thereof in preparing an experimental model drugs related to dopamine receptors and 5-HT receptors or a medicament for treating or preventing a disease related to dopamine receptors and 5-HT receptors.
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Paragraph 0151; 0152
(2015/05/26)
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- Synthesis and characterization of AlCl3 impregnated molybdenum oxide as heterogeneous nano-catalyst for the Friedel-Crafts acylation reaction in ambient condition
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Aluminum trichloride (AlCl3) impregnated molybdenum oxide heterogeneous nano-catalyst was prepared by using simple impregnation method. The prepared heterogeneous catalyst was characterized by powder X-ray diffraction, FT-IR spectroscopy, solid-state NMR spectroscopy, SEM imaging, and EDX mapping. The catalytic activity of this protocol was evaluated as heterogeneous catalyst for the Friedel-Crafts acylation reaction at room temperature. The impregnated MoO4(AlCl2)2 catalyst showed tremendous catalytic activity in Friedel-Crafts acylation reaction under solvent-free and mild reaction condition. As a result, 84.0% yield of acyl product with 100% consumption of reactants in 18 h reaction time at room temperature was achieved. The effects of different solvents system with MoO4(AlCl2)2 catalyst in acylation reaction was also investigated. By using optimized reaction condition various acylated derivatives were prepared. In addition, the catalyst was separated by simple filtration process after the reaction and reused several times. Therefore, heterogeneous MoO4(AlCl2)2 catalyst was found environmentally benign catalyst, very convenient, high yielding, and clean method for the Friedel-Crafts acylation reaction under solvent-free and ambient reaction condition.
- Jadhav, Arvind H.,Chinnappan, Amutha,Hiremath, Vishwanath,Seo, Jeong Gil
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p. 8243 - 8250
(2015/11/27)
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- A chemoselective α-aminoxylation of aryl ketones: a cross dehydrogenative coupling reaction catalysed by Bu4NI
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Tetrabutyl ammonium iodide (TBAI) catalyzed α-aminoxylation of ketones using aq. TBHP as an oxidant has been accomplished. We have shown that the CDC (cross dehydrogenative coupling) reactions of ketones with N-hydroxyimidates such as N-hydroxysuccinimide (NHSI), N-hydroxyphthalimide (NHPI), N-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) lead to the corresponding oxygenated products in good to moderate yields. The application of this method has been demonstrated by transforming a few coupled products into synthetically useful intermediates and products.
- Siddaraju, Yogesh,Prabhu, Kandikere Ramaiah
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supporting information
p. 11651 - 11656
(2015/12/08)
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- Ruthenium-catalyzed tandem-isomerization/asymmetric transfer hydrogenation of allylic alcohols
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A one-pot procedure for the direct conversion of racemic allylic alcohols to enantiomerically enriched saturated alcohols is presented. The tandem-isomerization/ asymmetric transfer hydrogenation process is efficiently catalyzed by [{Ru(p-cymene)Cl2}2] in combination with the a-amino acid hydroxyamide ligand 1, and performed under mild conditions in a mixture of ethanol and THF. The saturated alcohol products are isolated in good to excellent chemical yields and in enantiomeric excess up to 93%.
- Slagbrand, Tove,Lundberg, Helena,Adolfsson, Hans
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p. 16102 - 16106
(2015/01/09)
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- TFAA/H3PO4-Mediated C-2 acylation of thiophene: A direct synthesis of known and novel thiophene derivatives of pharmacological interest
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A number of aliphatic and aromatic carboxylic acids were reacted with thiophene in the presence of trifluoroacetic anhydride and H3PO 4 to give a variety of acylated thiophenes in good to excellent yields. The methodology was used to prepare known nonsteroidal anti-inflammatory drug-based novel compounds of potential pharmacological significances. Molecular modeling studies were carried out by using nonsteroidal anti-inflammatory drug-based thiophene derivatives to assess their cyclooxygenase inhibiting potential in silico. On the basis of docking studies followed by subsequent in vitro assay, indomethacin-based thiophene derivative was identified as a novel cyclooxygenase-2 inhibitor with balanced selectivity.
- Bindu,Naini, Shravan Reddy,Shanmukha Rao,Dubey,Pal, Sarbani
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p. 586 - 593
(2014/06/10)
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- A simple and efficient synthesis of substituted 2,2′-bithiophene and 2,2′:5′,2″-terthiophene
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A simple and efficient approach is developed for the synthesis of substituted 2,2′-bithiophene- and 2,2′:5′,2″- terthiophene-5-carboxylic acids and esters which is based on thiophene ring closure in the Fiesselmann reaction. Using this method, derivatives containing a long alkyl chain with or without an end functional group or an aryl substituent can be conveniently prepared.
- Kostyuchenko, Anastasia S.,Averkov, Alexey M.,Fisyuk, Alexander S.
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supporting information
p. 1833 - 1835
(2014/05/06)
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- Oxidative coupling of 1,7,8-unsubstituted BODIPYs: Synthesis and electrochemical and spectroscopic properties
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We report the synthesis of BODIPYs with unsubstituted 1,7,8-positions and their dimerization by oxidative coupling with phenyliodine(III)- bis(trifluoroacetate) (PIFA). This dimerization was achieved for BODIPYs substituted in the 3,5-positions with either methyl or thienyl groups. The position and the type of the linkage in the resulting dimers depended on the nature of the substituent. The 3,5-dimethyl-BODIPY dyes were linked either via direct 1,1′-pyrrole-pyrrole coupling or via a 1,3′-methylene bridge. The 3,5-dithienyl-BODIPY dyes provided, in excellent yields, unique compounds linked exclusively via the α-thienyl positions. All dyes were unreactive in the 8-position. Electrochemical and spectroscopic measurements on the monomers and dimers provided evidence of interactions between the two halves of the dimers. Thus, oxidation and reduction potentials were split by up to 210 mV, and modest excitonic coupling and an internal charge transfer were observed in some cases.
- Poirel, Arnaud,De Nicola, Antoinette,Retailleau, Pascal,Ziessel, Raymond
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p. 7512 - 7525
(2012/11/13)
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- Kinetic resolution of aryl alkenylcarbinols catalyzed by Fc-PIP
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An effective kinetic resolution of a variety of aryl alkenylcarbinols catalyzed by nonenzymatic acyl transfer catalyst Fc-PIP was developed, affording corresponding unreacted alcohols in good to excellent ee value up to 99% and with selectivity factors up to 24.
- Hu, Bin,Meng, Meng,Jiang, Shanshan,Deng, Weiping
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scheme or table
p. 1289 - 1294
(2012/08/28)
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- N, N′-dioxide-Cu(OTf)2 complex catalyzed highly enantioselective amination reaction of N-acetyl enamide
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The N,N′-dioxide-Cu(OTf)2 complexes were applied in the asymmetric amination reaction of N-acetyl enamides with dialkyl azodicarboxylate, giving the corresponding products in good yields with high enantioselectivities (up to 91% ee). Precursors of vicinal diamine were readily obtained with excellent diastereoselectivities (>95:5) by NaBH4 reduction.
- Chang, Lu,Kuang, Yulong,Qin, Bo,Zhou, Xin,Liu, Xiaohua,Lin, Lili,Feng, Xiaoming
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supporting information; scheme or table
p. 2214 - 2217
(2010/08/06)
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- Hair growth stimulator property of thienyl substituted pyrazole carboxamide derivatives as a cb1 receptor antagonist with in vivo antiobesity effect
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A few thienyl substituted pyrazole derivatives were synthesized to aid in the characterization of the cannabinoid receptor antagonist and also to serve as potentially useful antiobesity agent. Structural requirements for selective CB1 receptor antagonistic activity of 5-thienyl pyrazole derivatives included the structural similarity with potent, specific antagonist rimonabant 1. Compound 3 has been identified as a hair growth stimulator and an antiobesity agent in animal models.
- Srivastava, Brijesh Kumar,Soni, Rina,Patel, Jayendra Z.,Joharapurkar, Amit,Sadhwani, Nisha,Kshirsagar, Samadhan,Mishra, Bhupendra,Takale, Vijay,Gupta, Sunil,Pandya, Purvi,Kapadnis, Prashant,Solanki, Manish,Patel, Harilal,Mitra, Prasenjit,Jain, Mukul R.,Patel, Pankaj R.
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scheme or table
p. 2546 - 2550
(2010/01/16)
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- Unexpectedly high activity of Zn(OTf)2·6H2O in catalytic Friedel-Crafts acylation reaction
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Zn(OTf)2·6H2O was used to promote Friedel-Crafts acylation of aromatics. The work describes the high activity and efficiency of Zn(OTf)2·6H2O in acylation of aromatics, and the catalyst has surpassed most metal triflates in dispensing when dried at high temperature under vacuum before use. Copyright Taylor & Francis Group, LLC.
- He, Fei,Wu, Huayue,Chen, Jiuxi,Su, Weike
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p. 255 - 264
(2008/03/17)
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- A new and highly efficient water-soluble copper complex for the oxidation of secondary 1-heteroaryl alcohols by tert-butyl hydroperoxide
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The water-soluble copper complex generated in situ from CuCl2 and 2,2′-biquinoline-4,4′-dicarboxylic acid dipotassium salt (BQC), has been revealed as a highly efficient and selective catalyst for the oxidation of secondary 1-heteroaryl alcohols to the corresponding heteroaromatic ketones with aqueous tert-butyl hydroperoxide, under mild conditions. The catalytic system is compatible with different heterocycles such as pyridines, pyrroles, indoles, thiophens, furans, thiazoles, and imidazoles.
- Boudreau, Josée,Doucette, Mike,Ajjou, Abdelaziz Nait
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p. 1695 - 1698
(2007/10/03)
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- Fluorous triphase and other multiphase systems
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A method of reacting a first non-fluorous compound to produce a second non-fluorous compound includes the steps of: contacting a first non-fluorous phase including the first non-fluorous compound with a first fluorous phase at a first phase interface, the first non-fluorous compound distributing between the first fluorous phase and the first non-fluorous phase; contacting the first fluorous phase with a second non-fluorous phase at a second phase interface; and including at least a third non-fluorous compound in the second non-fluorous phase that reacts with the first non-fluorous compound to produce the second non-fluorous compound, the second non-fluorous compound having a distribution coefficient less than the first non-fluorous compound. For example, the first non-fluorous compound can be dibromine or diiodine, and the second non-fluorous compound can be an alkene.
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- Cp*Ru(PN) complex-catalyzed isomerization of allylic alcohols and its application to the asymmetric synthesis of muscone
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Highly efficient isomerization of allylic alcohols into saturated carbonyls is accomplished using the catalyst system of Cp*RuCl[Ph2P(CH2)2NH2-κ2-P,N]-KOt-Bu (Cp* = η5-C5(CH3)5) under mild conditions. Mechanistic consideration based on isotope-labeling experiments indicated the present reaction is applicable to the asymmetric isomerization of racemic sec-allylic alcohols with a prochiral olefin via dynamic kinetic resolution. A concise asymmetric synthesis of muscone has been achieved, where the asymmetric isomerization using an optically active ligand is a key reaction. Copyright
- Ito, Masato,Kitahara, Sachiko,Ikariya, Takao
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p. 6172 - 6173
(2007/10/03)
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- Oppenauer-type oxidation of secondary alcohols catalyzed by homogeneous water-soluble complexes
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The catalytic system composed of [Ir(COD)Cl]2, 2,2′-biquinoline-4,4′-dicarboxylic acid dipotassium salt (BQC), and sodium carbonate is highly efficient for the selective oxidation of benzylic, 1-heteroaromatic, aliphatic, and allylic secondary alcohols using catalyst:substrate ratios ranging from 0.4% to 2.5%. Sterically hindered allylic alcohols undergo selectively good conversions to the corresponding enones, while unhindered ones are completely isomerized to saturated ketones. Mercury tests indicate that the catalytic process is likely homogeneous. The mechanism proposed for this Oppenauer-type oxidation including the isomerization process is based on iridium-alkoxide species.
- Ajjou, Abdelaziz Nait,Pinet, Jean-Louis
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p. 702 - 710
(2007/10/03)
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- Friedel-Crafts acylation of furan and thiophene using ytterbium(III) trifluoromethanesulfonate in [BPy][BF4] ionic liquid
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Friedel-Crafts reactions of furan and thiophene have been catalyzed by ytterbium(III) trifluoromethanesulfonate in [BPy][BF4] (n-butylpyridinium tetrafluoroborate) ionic liquid to produce intermediates of pharmaceuticals with good yields. The catalyzing system [BPy][BF 4]/Yb(OTf)3 could be reused.
- Su, Weike,Wang, Yan
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p. 398 - 400
(2007/10/03)
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- Fluorous triphase and other multiphase systems
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A method of reacting a first non-fluorous compound to produce a second non-fluorous compound includes the steps of: contacting a first non-fluorous phase including the first non-fluorous compound with a first fluorous phase at a first phase interface, the first non-fluorous compound distributing between the first fluorous phase and the first non-fluorous phase; contacting the first fluorous phase with a second non-fluorous phase at a second phase interface; and including at least a third non-fluorous compound in the second non-fluorous phase that reacts with the first non-fluorous compound to produce the second non-fluorous compound, the second non-fluorous compound having a distribution coefficient less than the first non-fluorous compound. For example, the first non-fluorous compound can be dibromine or diiodine. and the second non-fluorous compound can be an alkene.
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- Ytterbium(III) trifluoromethanesulfonate catalysed Friedel-Crafts acylation of substituted thiophenes
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Ytterbium(III) trifluoromethanesulfonate [Yb(OTf)3] has been used to catalyse Friedel-Crafts acylation of substituted thiophenes in different solvents to produce several intermediates of pharmaceuticals and pesticides with good yields. The amount of catalysis was discussed and Yb(OTf)3 could be reused without loss of activity.
- Su, Weike,Jin, Can
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p. 694 - 695
(2007/10/03)
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- Phase-vanishing method: Friedel-Crafts acylation of thiophene with tin tetrachloride and its application to convenient parallel synthesis
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Phase-vanishing (PV) method was applied to Friedel-Crafts acylations of aromatic compounds with tin tetrachloride as a Lewis acid. The reaction proceeded smoothly and acylation products were obtained in good yield. Parallel, four different Friedel-Crafts acylation reactions were carried out successfully based on the present PV method.
- Matsubara, Hiroshi,Yasuda, Shinji,Ryu, Ilhyong
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p. 247 - 249
(2007/10/03)
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- 2-(Trifluoromethylsulfonyloxy)pyridine as a Reagent for the Ketone Synthesis from Carboxylic Acids and Aromatic Hydrocarbons
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A new reagent 2-(trifluoromethylsulfonyloxy)pyridine (TFOP) was prepared by the reaction of sodium salt of 2-pyridinol with trifluoromethylsulfonyl chloride in dioxane.The conpound TFOP in trifluoroacetic acid has been found to intermolecularly dehydrate from benzoic acid and aromatic hydrocarbons to give the corresponding benzophenones in high yield.It was further elucidated, in the reaction of fluorene, that a variety of carboxylic acids can be used as the acyl precursor for the aromatic ketone synthesis in conjunction with the TFOP/TFA system.This acylation procedure has been applied to the synthesis of 2-acylthiophenes, which are hard to prepare in a satisfactory yield by the classical Friedel-Crafts reaction using aluminum chloride as the catalyst.
- Keumi, Takashi,Yoshimura, Kiichiro,Shimada, Masakazu,Kitajima, Hidehiko
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p. 455 - 460
(2007/10/02)
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- THE NAFION-H-CATALYZED ACYLATION OF THIOPHENE WITH ACID ANHYDRIDES
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The reaction of thiophene with acyclic acid anhydrides in the presence of Nafion-H (fluorocarbon resin sulfonic acid) afforded the corresponding 2-acylthiophenes in moderate yields.Acylation with cyclic acid anhydrides gave only low yields, however.The Nafion-H catalyst could be reused for the acylation with a little loss of activity.
- Konishi, Hisatoshi,Suetsugu, Kazuhiro,Okano, Tamon,Kiji, Jitsuo
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p. 957 - 958
(2007/10/02)
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