- Self-assembled ionophores as phase transfer catalysts
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The nucleoside, 5'-(t-butyl-dimethylsilyl)-2',3'-O-isopropylidene isoG 1, catalyzes the S(N)2 reactions of alkali and ammonium iodides with dodecyl mesylate 2 under both liquid-liquid and solid-liquid phase transfer conditions. IsoG 1 self-associates to give a complex that extracts the salts into CDCl3 solution. Sodium iodide, in the presence of isoG 1, reacts faster with 2 than the other iodides under solid-liquid conditions. This reactivity difference is attributed to the open-faced structure of the ionophore-M+ complex under solid-liquid conditions.
- Marlow, Allison L.,Davis, Jeffery T.
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Read Online
- Activity and behavior of imidazolium salts as a phase transfer catalyst for a liquid-liquid phase system
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The structure-activity relationship and behavior of N,N′-dialkylimidazolium salts as a phase transfer and/or ion-exchange catalyst in a liquid-liquid phase system were investigated for the reactions such as β-elimination reaction of alkyl halides, nucleophilic epoxidation of α,β-unsaturated carbonyl compounds, alkylation of active methylenes, and nucleophilic substitution reaction.
- Okamoto, Sentaro,Takano, Kouichi,Ishikawa, Tomohiro,Ishigami, Satoshi,Tsuhako, Akiko
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Read Online
- Contra-thermodynamic Olefin Isomerization by Chain-Walking Hydroboration and Dehydroboration
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We report a dehydroboration process that can be coupled with chain-walking hydroboration to create a one-pot, contra-thermodynamic, short-or long-range isomerization of internal olefins to terminal olefins. This dehydroboration occurs by a sequence comprising activation with a nucleophile, iodination, and base-promoted elimination. The isomerization proceeds at room temperature without the need for a fluoride base, and the substrate scope of this isomerization is expanded over those of previous isomerizations we have reported with silanes.
- Bloomer, Brandon,Butcher, Trevor W.,Ciccia, Nicodemo R.,Conk, Richard J.,Hanna, Steven,Hartwig, John F.
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supporting information
p. 1005 - 1010
(2022/02/10)
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- NUCLEOSIDE PRODRUGS AND USES RELATED THERETO
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Disclosed are acyclic nucleoside prodrugs with improved metabolic stability and oral bioavailability. In general, the prodrugs are derivatives of acyclic nucleoside phosphonates containing a lipid-like moiety that can increase oral absorption and subsequent stability in the liver and plasma. Preferably, the lipid-like moiety can resist enzyme-mediated ω-oxidation, such as ω -oxidation catalyzed by cytochrome P450 enzymes. Also disclosed are pharmaceutical formulations of the acyclic nucleoside prodrugs. The acyclic nucleoside prodrugs and pharmaceutical formulations thereof can be used to treat viral infections, such as HIV infections, and/or viral-associated cancer, such as HPV-associated cancers.
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Page/Page column 131; 132
(2021/02/26)
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- ω-Functionalized Lipid Prodrugs of HIV NtRTI Tenofovir with Enhanced Pharmacokinetic Properties
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Tenofovir (TFV) is the cornerstone nucleotide reverse transcriptase inhibitor (NtRTI) in many combination antiretroviral therapies prescribed to patients living with HIV/AIDS. Due to poor cell permeability and oral bioavailability, TFV is administered as one of two FDA-approved prodrugs, both of which metabolize prematurely in the liver and/or plasma. This premature prodrug processing depletes significant fractions of each oral dose and causes toxicity in kidney, bone, and liver with chronic administration. Although TFV exalidex (TXL), a phospholipid-derived prodrug of TFV, was designed to address this issue, clinical pharmacokinetic studies indicated substantial hepatic extraction, redirecting clinical development of TXL toward HBV. To circumvent this metabolic liability, we synthesized and evaluated ω-functionalized TXL analogues with dramatically improved hepatic stability. This effort led to the identification of compounds 21 and 23, which exhibited substantially longer t1/2 values than TXL in human liver microsomes, potent anti-HIV activity in vitro, and enhanced pharmacokinetic properties in vivo.
- Bartsch, Perry W.,Basson, Adriaan E.,Burton, Samantha L.,Bushnev, Anatoliy,D'Erasmo, Michael,Dasari, Madhuri,Derdeyn, Cynthia A.,Giesler, Kyle E.,Hwang, Soyon S.,Iskandar, Sabrina,Liotta, Dennis C.,Miller, Eric J.,Pribut, Nicole,Raghuram, Akshay,Sharma, Savita K.
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p. 12917 - 12937
(2021/09/13)
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- Quinim: A New Ligand Scaffold Enables Nickel-Catalyzed Enantioselective Synthesis of α-Alkylated ?-Lactam
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Herein, we report a nickel-catalyzed reductive cross-coupling reaction of easily accessible 3-butenyl carbamoyl chloride with primary alkyl iodide to access the chiral α-alkylated pyrrolidinone with broad substrate scope and high enantiomeric excess. The current art of synthesis still remains challenging on the enantioselective α-monoalkylation of pyrrolidinones. The newly designed chiral 8-quinoline imidazoline ligand (Quinim) is crucial for maintaining the reactivity and enantioselectivity to ensure the reductive cyclization of monosubstituted alkenes for unprecedented synthesis of chiral non-aromatic heterocycles.
- Chen, Yifeng,Qu, Jingping,Wu, Xianqing
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supporting information
p. 15654 - 15660
(2020/10/18)
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- Photocatalytic Aerobic Phosphatation of Alkenes
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A catalytic regime for the direct phosphatation of simple, non-polarized alkenes has been devised that is based on using ordinary, non-activated phosphoric acid diesters as the phosphate source and O2 as the terminal oxidant. The title method enables the direct and highly economic construction of a diverse range of allylic phosphate esters. From a conceptual viewpoint, the aerobic phosphatation is entirely complementary to traditional methods for phosphate ester formation, which predominantly rely on the use of prefunctionalized or preactivated reactants, such as alcohols and phosphoryl halides. The title transformation is enabled by the interplay of a photoredox and a selenium π-acid catalyst and involves a sequence of single-electron-transfer processes.
- Depken, Christian,Kr?tzschmar, Felix,Rieger, Rene,Rode, Katharina,Breder, Alexander
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supporting information
p. 2459 - 2463
(2018/01/27)
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- A mild and highly chemoselective iodination of alcohol using polymer supported DMAP
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The synthesis of organic compounds using polymer supported catalysts and reagents, where the required product is always in solution, has been of great interest in recent years, both in industries and academia especially in pharmaceutical research. Here, a simple and efficient method for conversion of alcohols into their iodides in high yield using polymer supported 4-(Dimethylamino)pyridine (DMAP) is described. Polymer supported DMAP is used in catalytic amount and is recovered and reused several times. Additionally, this method is highly chemoselective. [Figure not available: see fulltext.]
- Das, Diparjun,H Anal, Jasha Momo,Rokhum, Lalthazuala
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p. 1695 - 1701
(2017/03/08)
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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
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Page/Page column 182; 183; 186
(2017/01/02)
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- Ruthenium bipyridyl tethered porous organosilica: A versatile, durable and reusable heterogeneous photocatalyst
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A versatile heterogeneous photocatalysis protocol was developed by using ruthenium bipyridyl tethered porous organosilica (Ru-POS). The versatility of the Ru-POS catalyst in organo-photocatalysis was explored by (i) oxidative aromatization of Hantzsch ester, (ii) reductive dehalogenation of alkyl halides, and (iii) functional group interconversion (FGI) of alcohols to alkyl halides. This journal is
- Jana, Avijit,Mondal, John,Borah, Parijat,Mondal, Sujan,Bhaumik, Asim,Zhao, Yanli
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supporting information
p. 10746 - 10749
(2015/06/30)
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- Application of "click" chemistry in solid phase synthesis of alkyl halides
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A convenient and highly selective microwave assisted procedure for the conversion of allylic, benzylic and aliphatic alcohols to their corresponding halides using polymer-bound triphenylphosphine and iodine is presented. In case of symmetrical diols, mono-iodination product is obtained in very high yield. Additionally, highly regioselective behavior is observed in our procedure. Simplicity in operation, no column chromatography required for the purification of the products, recyclability of the reagents used, short reaction times and good to excellent yields are the advantages of our protocol. Most functional groups remain unaffected under our reaction condition.
- Das, Diparjun,Chanda, Tridib,Rokhum, Lalthazuala
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p. 775 - 783
(2016/01/20)
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- Reduction of benzylic alcohols and α-hydroxycarbonyl compounds by hydriodic acid in a biphasic reaction medium
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The synthetic protocol for the reduction of alcohols to hydrocarbons by using hydriodic acid, first described by Kiliani more than 140 years ago, was improved to be more applicable to organic synthesis. Instead of a strongly acidic, aqueous solution, a biphasic toluene-water reaction medium was used, which allowed the conversion of primary, secondary and tertiary benzylic alcohols, in good yields and short reaction times, into the corresponding hydrocarbons. Red phosphorous was used as the stoichiometric reducing agent. Keto, ester, amide or ether groups are tolerated, and catalytic amounts of hydriodic acid (0.2 equiv) in the presence of 0.6 equiv phosphorous are sufficient to achieve conversion.
- Dobmeier, Michael,Herrmann, Josef M.,Lenoir, Dieter,Koenig, Burkhard
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supporting information; experimental part
p. 330 - 336
(2012/05/20)
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- Efficient procedures to prepare primary and secondary alkyl halides from alkanols via the corresponding sulfonates under mild conditions
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The study presented herein shows that sulfonate/halide exchange can be advantageously performed in THF to avoid several side reactions such as elimination and epimerization when the reaction is performed from a chiral alkyl sulfonate or a substrate having a C-H acidic chiral center. The main limitation of this procedure was found to be the conversion of secondary alkyl sulfonates to alkyl chlorides. In this case, the addition of a catalytic amount of manganese chloride clearly accelerates the rate and the efficiency of the reaction. Copyright
- Cahiez, Gerard,Gager, Olivier,Moyeux, Alban,Delacroix, Thomas
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supporting information; experimental part
p. 1519 - 1528
(2012/07/03)
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- Synthesis and photophysical properties of doubly porphyrin-substituted cyanine dye
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New porphyrin-(cyanine dye) composites, in which two porphyrins are bridged by a cyanine dye through triple bonds, were synthesized. In the UV-vis absorption spectra of the composites, the Soret band and Q-band were red-shifted to 436 and 575640 nm, respectively. The absorption originating from the cyanine dye portion was also red-shifted from 710 nm to 764 nm, suggesting the expansion of πconjugation over the porphyrin and cyanine dye parts. Fluorescence studies suggested that energy transfer from the porphyrin portion to the cyanine dye moiety occurred. The fluorescence intensity decreased with increasing dielectric constants of solvents, suggesting intramolecular photoinduced electron transfer from the porphyrin to the cyanine dye parts. The effective two-photon absorption (2PA) cross-section values were measured using a nanosecond open aperture Z-scan method. The maximum effective 2PA cross-section and two-photon excited fluorescence cross-section values were 33,000 GM and 4,800 GM, respectively, at 860 nm in toluene/pyridine (95:5).
- Ogawa, Kazuya,Nagatsuka, Yasunori,Kobuke, Yoshiaki
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experimental part
p. 678 - 685
(2012/07/14)
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- Synthesis of 6-thio pseudo glycolipids and their orientation on a gold slide studied by IRRAS
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We have synthesized four 6-thio pseudo glycolipid analogues and assessed how two of them self-assembled on a gold surface. These structures were designed as candidate tethers molecules to anchor bilayer lipid membranes on gold. 6-Deoxy-6-thiogalactose was chosen to anchor the macromolecule to the gold and define an aqueous zone at the gold surface. A long alkane chain (C-12 or C-18) linked to the anomeric position of the sugar residue was chosen to anchor a bilayer lipid membrane. The linkage between the carbohydrate and the hydrophobic chains is either a glycosidic bond or a 1,4-disubstituted triazole formed by copper(I)-catalysed alkyne-azide cycloaddition (CuAAC) of the propargyl glycoside with azido-dodecane and azido-octadecane. We are expecting that the hydrocarbon chains will orient themselves perpendicular to the gold surface and be incorporated into the first leaflet of the bilayer membrane. We have studied self assembled monolayers of the C-12 aglycone analogues on gold using infrared reflection absorption spectroscopy (IRRAS). We compared the results given by the IRRAS experiments to the IR spectra recorded by attenuated total reflection (ATR) spectroscopy on films of the randomly oriented analogues. Our results demonstrate that the C-12 analogues did bind to gold and did orient themselves perpendicular to the gold slide.
- Guillemineau, Mickael,Singh, Serena,Grossutti, Michael,Auzanneau, France-Isabelle
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experimental part
p. 2723 - 2730
(2011/03/17)
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- Regioselective functionalization of alkanes by sequential dehydrogenation-hydrozirconation
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We have succeeded in formal regioselective functionalization of alkanes by iridium-catalyzed dehydrogenation, hydrozirconation of the resulting alkenes, and electrophilic reaction of the generated alkylzirconium intermediate.
- Kuninobu, Yoichiro,Ureshino, Tomonari,Yamamoto, Shun-Ichi,Takai, Kazuhiko
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supporting information; experimental part
p. 5310 - 5312
(2010/10/21)
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- A mild, phosphine-free method for the conversion of alcohols into halides (Cl, Br, I) via the corresponding O-alkyl isoureas
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A novel procedure for the conversion of primary and secondary alcohols into the corresponding alkyl chlorides, bromides and iodides is described. The transformation is high-yielding in the case of chlorides and bromides, tolerates a range of functional groups, and does not rely on the use of phosphines.
- Li, Zhengning,Crosignani, Stefano,Linclau, Bruno
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p. 8143 - 8147
(2007/10/03)
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- Triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone as a new, selective and neutral system for the facile conversion of alcohols, thiols and selenols to alkyl halides in the presence of halide ions
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A mixture of triphenylphosphine (Ph3P) and 2,3-dichloro-5,6-dicyanobenzoquinone in CH2Cl2 affords a complex which in the presence of R4NX (X=Cl, Br, I) converts alcohols, thiols and selenols into their corresponding alkyl halides in high yields at room temperature. The method is highly selective for the conversion of 1° alcohols in the presence of 2° ones and also 1° and 2° alcohols in the presence of 3° alcohols, thiols, epoxides, trimethylsilyl- and tetrahydropyranyl ethers, 1,3 dithianes, disulfides, and amides.
- Iranpoor,Firouzabadi,Aghapour,Vaez zadeh
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p. 8689 - 8693
(2007/10/03)
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- A facile conversion of thiols to alkyl halides by triphenylphosphine/N-halosuccinimides
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Thiols are efficiently converted to alkyl halides in high to excellent yields when treated with triphenylphosphin/N-halosuccinimide (halogen: Br,Cl, and I) in dichloromethane at room temperature.
- Iranpoor,Firouzabadi,Aghapour
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p. 1176 - 1178
(2007/10/03)
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- β-Cyclodextrin-Epichlorohydrin Copolymers as Efficient Catalysts in Phase-Transfer-Catalyzed Nucleophilic Substitution Reactions
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Copolymers of β-cyclodextrin (β-CD) with epichlorohydrin showed much higher phase-transfer catalytic activity than β-CD in liquid-liquid two-phase nucleophilic displacement reactions.The enhanced efficiency of the polymer catalysts was attributed to the cooperative effect of more than one β-CD group in polymers in bringing a substrate from an organic phase to an aqueous phase.
- Tanaka, Nobuo,Yamaguchi, Atsumi,Araki, Yoshio,Araki, Mikio
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p. 715 - 718
(2007/10/02)
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- A New and Efficient One-Pot Preparation of Alkyl Halides From Alcohols
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Primary alkanols and 2-alkenols are converted into the corresponding halides in high yield by a one-pot, two-step reaction via transformation into intermediate trifluoroacetates followed by nucleophilic substitution with lithium halides.
- Camps, Francisco,Gasol, Vicens,Guerrero, Angel
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p. 511 - 512
(2007/10/02)
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- NEW PREPARATION OF ALKYL IODIDES FROM THE CORRESPONDING ALCOHOLS
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It is shown that alkyl iodides can be obtained from the corresponding alkyl α-chloroethyl carbonate and NaI or by direct reaction between the alcohol, α-chloroethyl chloroformate and NaI.
- Brunet, J. J.,Laurent, H.,Caubere, P.
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p. 5445 - 5446
(2007/10/02)
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- PREPARATION OF ALKYL HALIDES VIA ORGANOTELLURIUMS
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The conversion of phenyltelluroalkanes to haloalkanes was studied in connection with the homologation of alkyl halides.Similar reactions of 1,1-bis(phenyltelluro)alkanes provided a new synthetic method of aldehydes.
- Chikamatsu, Kiyofumi,Otsubo, Tetsuo,Ogura, Fumio,Yamaguchi, Hachiro
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p. 1081 - 1084
(2007/10/02)
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- Divalent Lanthanide Derivatives in Organic Synthesis. 1. Mild Preparation of SmI2 and YbI2 and Their Use as Reducing or Coupling Agents
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The facile synthesis of SmI2 and YbI2 from corresponding metals in THF is described.The reactivity of these potentially powerful reducing agents toward a variety functional groups is tested.Epoxides and sulfoxides are deoxygenated.Aldehydes are selectively reduced in presence of ketones.Alkyl halides or tosylates are converted into alkanes.Only coupling products are obtained from benzylic or allylic halides.In the presence of a SmI2-THF solution, tertiary alcohols are easily obtained from reactions between ketones and alkyl halides.In a similar manner, SmI2 promotes straightforward alkylation of ketones by alkyl sulfonates.Selective addition of polyfunctional halides or tosylates to ketones may be performed.In these reactions, catalytic amounts of FeCl3 enhance the reactivity.
- Girard, P.,Namy, J. L.,Kagan, H. B.
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p. 2693 - 2698
(2007/10/02)
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