- Thiourea-Mediated Halogenation of Alcohols
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The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
- Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
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p. 12901 - 12911
(2020/11/26)
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- Promotion of Appel-type reactions by N-heterocyclic carbenes
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N-Heterocyclic carbenes (NHCs) have been extensively used as a versatile class of catalysts and ligands in organocatalytic and organometallic chemistry. However, there are only a small number of synthetic applications where they act as reagents. Here we demonstrate that NHCs can be used as stoichiometric redox reagents for Appel-type halogenation reactions of alcohols. This new reactivity reveals a fresh and interesting aspect and enriches the chemistry of NHCs in an underexplored area. The potential of performing this chemical transformation at the catalytic level using an NHC-oxide derivative is also investigated.
- Hussein, Mohanad A.,Nguyen, Thanh Vinh
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supporting information
p. 7962 - 7965
(2019/07/12)
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- Nucleophilic Substitutions of Alcohols in High Levels of Catalytic Efficiency
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A practical method for the nucleophilic substitution (SN) of alcohols furnishing alkyl chlorides, bromides, and iodides under stereochemical inversion in high catalytic efficacy is introduced. The fusion of diethylcyclopropenone as a simple Lewis base organocatalyst and benzoyl chloride as a reagent allows notable turnover numbers up to 100. Moreover, the use of plain acetyl chloride as a stoichiometric promotor in an invertive SN-type transformation is demonstrated for the first time. The operationally straightforward protocol exhibits high levels of stereoselectivity and scalability and tolerates a variety of functional groups.
- Stach, Tanja,Dr?ger, Julia,Huy, Peter H.
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supporting information
p. 2980 - 2983
(2018/05/28)
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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; 185
(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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- Halogen Exchange Reaction of Aliphatic Fluorine Compounds with Organic Halides as Halogen Source
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The halogen exchange reaction of aliphatic fluorine compounds with organic halides as the halogen source was achieved. Treatment of alkyl fluorides (primary, secondary, or tertiary fluorides) with a catalytic amount of titanocene dihalides, trialkyl aluminum, and polyhalomethanes (chloro or bromo methanes) as the halogen source gave the corresponding alkyl halides in excellent yields under mild conditions. In the case of a fluorine/iodine exchange, no titanocene catalyst is needed. Only C-F bonds are selectively activated under these conditions, whereas alkyl chlorides, bromides, and iodides are tolerant to these reactions.
- Mizukami, Yuki,Song, Zhiyi,Takahashi, Tamotsu
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p. 5942 - 5945
(2016/01/09)
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- Synthesis of some acyclic quaternary ammonium compounds. Alkylation of secondary and tertiary amines in a two-phase system
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A series of acyclic symmetrical and asymmetrical quaternary ammonium chlorides of the general formula R1R2R3N+AR4Cl- (R1 = Me, Bu; R2 = n-C12H25, PhCH2, C n H2n+1(OCH2CH2) m, n = 9 and 12, m = 1 and 2; R3 = n-C12H25, PhCH2, HOCH2CH2,-OOCCH2; R4 = n-C12H25, PhCH2; A = (CH2CH2O)1,2, CH2C(O)O) was synthesized by the alkylation of tertiary amines in a two-phase system containing water. A convenient method for the synthesis of the initial symmetrical and asymmetrical tertiary amines of the general formula MeNR1R2 (R1 = Me, Bu; R2 = n-C12H25, PhCH2, CnH2n+1(OCH2CH2) m, n = 9 and 12, m = 1 and 2) in an organic phase-aqueous phase heterogeneous system, which allows the use of aqueous solutions of alkali and amines, was developed. The improved method for the preparation of intermediate ethylene glycol and diethylene glycol monoethers is monoalkylation of glycols in dioxane using solid KOH in a two-phase system.
- Kharlamov,Artyushin,Bondarenko
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p. 2445 - 2454
(2015/08/03)
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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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- Arylsulfur trifluorides: Improved method of synthesis and use as in situ deoxofluorination reagents
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Building on recent results of Umemoto and Winter, an improved method of synthesis of arylsulfur trifluorides, including the excellent, new deoxofluorination reagent Fluolead, is hereby reported. The method utilizes Br2 and KF as oxidizing and fluorinating reagents for efficient, high yield conversion of aryl disulfides and mercaptans to arylsulfur trifluorides. It has also been shown that both Fluolead and mesitylsulfur trifluoride may be generated in acetonitrile and used as in situ deoxofluorination reagents for conversion of either aldehydes or ketones to their respective gem-difluoro compounds. An analysis of the probable mechanism of action, including computational efforts, allows postulation of a rationale for the highly variable reactivities of different arylsulfur trifluorides as deoxofluorination reagents.
- Xu, Wei,Martinez, Henry,Dolbier Jr., William R.
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experimental part
p. 482 - 488
(2011/08/03)
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- A photoirradiative phase-vanishing method: Efficient generation of HBr from alkanes and molecular bromine and its use for subsequent radical addition to terminal alkenes
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A triphasic phase-vanishing (PV) system comprised of an alkane, perfluorohexanes, and bromine was successfully combined by photoirradiation to efficiently generate hydrogen bromide, which underwent radical addition with 1-alkenes in the hydrocarbon layer to afford terminal bromides in high yields. Georg Thieme Verlag Stuttgart.
- Matsubara, Hiroshi,Tsukida, Masaaki,Ishihara, Daisuke,Kuniyoshi, Kenji,Ryu, Ilhyong
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experimental part
p. 2014 - 2018
(2010/10/02)
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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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body text
p. 5310 - 5312
(2010/10/21)
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- An asymmetric aminohydroxylation route to cis-2,6-disubstituted piperidine-3-ol: application to the synthesis of (-)-deoxocassine
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A highly efficient, flexible, and convergent route to cis-2,3,6-trisubstituted piperidines has been developed employing the Sharpless asymmetric aminohydroxylation and stereoselective reductive amination by catalytic hydrogenation as the key steps. Its usage is illustrated by the short synthesis of the piperidine-3-ol alkaloid, (-)-deoxocassine.
- Kandula, Subba Rao V.,Kumar, Pradeep
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p. 9942 - 9948
(2007/10/03)
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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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- Hypocholesterolemic activity of hesperetin derivatives
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Hesperetin ester and ether derivatives possessing a long alkyl chain were synthesized for examining their hypocholesterolemic activities in high cholesterol-fed mice. Hesperetin 7-O-lauryl ether (4b) and hesperetin 7-O-oleyl ether (4e) exhibited strong cholesterol-lowering effects.
- Jeong, Tae-Sook,Kim, Eun Eai,Lee, Chul-Ho,Oh, Jung-Hoon,Moon, Surk-Sik,Lee, Woo Song,Oh, Goo-Taeg,Lee, Sangku,Bok, Song-Hae
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p. 2663 - 2665
(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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- One-pot synthesis of aryl sulfones from alcohols
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A one-pot synthesis of aryl sulfones from primary alcohols is described. Alcohols were treated with N-bromosuccinimide and triphenylphosphine, followed by addition of sodium arenesulfinate with a catalytic amount of tetrabutylammonium iodide to afford the aryl sulfones in good to high yields.
- Murakami, Teiichi,Furusawa, Kiyotaka
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p. 479 - 482
(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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- Calamitic organometallic liquid crystals with terminal metal. Syntheses and liquid crystal properties of dicarbonylrhodium(I) β-diketonate complexes
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A series of novel organometallic complexes based on γ-substituted β-diketone ligands with terminal metal Rh(I) have been prepared by reaction of the ligands with [Rh(CO)2(μ-Cl)]2. The mesomorphism of the ligands and complexes has been investigated using DSC and polarizing microscope. It is found that non-mesogenic ligands with n=7, 8, 9, 10, 11 can form liquid crystalline phase by direct coordination to metal. The effect of the terminal carbon number on the mesomorphism has also been discussed.
- Wan, Wen,Guang, Wen-Jie,Zhao, Ke-Qin,Zheng, Wei-Zhong,Zhang, Liang-Fu
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p. 157 - 161
(2007/10/03)
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- Syntheses of long-chain quaternary ammonium salts from fatty alcohols by microwave irradiation
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The phase-transfer catalysts, long-chain quaternary ammonium salts, were rapidly synthesized from fatty alcohols by the reactions with hydrogen halides in the presence of trialkyl amines under microwave irradiation. The catalysts could be widely applied in a variety of quick and new organic reactions, whether by conventional heating or under microwave irradiation. The reaction efficiencies under microwave irradiation were higher than those obtained with conventional heating.
- Jiang,Hu,Pang,Yuan
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p. 847 - 850
(2007/10/03)
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- Total Synthesis of (2S,3S,4R)-2--16-methylheptadecane-1,3,4-triol 3,4-dibenzoate, a Partially Protected Ceramide Part of Sponge Cerebrosides
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(2S,3S,4R)-2--16-methylheptadecane-1,3,4-triol 3,4-dibenzoate 32, apertially protected ceramide part of a cerebroside from the marine sponge Halichondria japonica, has been synthesized from L-ascorbic acid, and its absolute stereochemistry has been determined.The key steps in the synthesis include the regioselective ring opening of chiral epoxide 5 with a 2-alkyl-2-lithio-1,3-dithiane and the introduction of a hydroxymethylene synthon using Dondoni's protocol to assemble C(1) and C(2) functionality.
- Nakashima, Hideki,Hirata, Norihiko,Iwamura, Takeru,Yamagiwa, Yoshiro,Kamikawa, Tadao
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p. 2849 - 2858
(2007/10/02)
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- A Convenient Conversion of Primary Amines into the Corresponding Halides Radical Promoted Halodeamination via N-Substituted-N-Tosylhydrazines
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Treatment of 1-substituted-1-tosylhydrazines with 2 equivalents of NCS or NBS in dry THF in presence of light affords the corresponding alkyl halides in good yields.This reaction presumably involves the initial formation of a stabilized hydrazyl radical which is halogenated in a radical chain process.Elimination of p-toluenesulfinic acid and extrusion of nitrogen leads to the corresponding alkyl halide.This route provides an improved method for halodeamination under neutral reaction conditions.
- Collazo, Luis R.,Guziec, Frank S.,Hu, Wei-Xiao Jr.,Pankayatselvan, Ratnadevi
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p. 7911 - 7914
(2007/10/02)
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- Process for preparing 1-dodecylazacycloheptane-2-one
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Disclosed is a process for preparing 1-dodecylazacyclo-heptane-2-one, the process comprising reacting azacylcloheptane-2-one with dodecyl halide in a substantially non-aqueous system in the presence of a phase-transfer catalyst represented by the formula STR1 wherein R1, R2, R3 and R4 are alkyl or aralkyl, or two or three of the groups R1, R2, R3 and R4, when taken together with nitrogen to which they are attached, form a heterocyclic group (in which case the remaining one or two of the groups being alkyl or aralkyl) and X? is a univalent anion.
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- CIS 1,2-FUNCTIONALIZATION OF CYCLOHEXANE USING SELENIUM INTERMEDIATES
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The trans 1,2-phenylseleno acetate, acetamide, alcohol and nitrile of cyclohexane may be oxidized at selenium by halogens and the phenylseleno moiety displaced by halide to give high yields of 1,2 halide-containing products with cis geometry.
- Morella, Angelo M.,Ward, A. David
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p. 2899 - 2900
(2007/10/02)
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- A NOVEL ONE STEP CONVERSION OF ALCOHOLS INTO ALKYL BROMIDES OR IODIDES
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Alcohols are converted in high yields into alkyl bromides or iodides by a one step reaction with N,N'-carbonyldiimidazole and an excess of reactive halides such as allyl bromide or methyl iodide.KEYWORDS - alcohol; N,N'-carbonyldiimidazole; bromination; iodination; 1-alkoxycarbonylimidazole; 1-alkoxycarbonyl-3-substituted imidazolium salt; allyl bromide; methyl iodide
- Kamijo, Tetsuhide,Harada, Hiromu,Iizuka, Kinji
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p. 4189 - 4192
(2007/10/02)
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- LIQUID CRYSTALLINE PROPERTIES OF 4-N-ALKOXYPHENYL 4-NITROBENZOATES.
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Twelve 4-alkoxyphenyl esters of 4-nitrobenzoic acid were synthesized. The mesophases were identified and the transition temperatures and enthalpies determined. The above series shows considerable similarity to the reverse analogues, i. e. , the 4-nitro-phenyl 4-n-alkoxybenzoates.
- Galewski,Sobczyk
-
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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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