- A metal-free iodine-mediated conversion of hydroxamates to esters
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A metal-, oxidant-, and additive-free conversion of hydroxamates to esters have been achieved using molecular iodine as the reagent using a novel but not-so-explored heron-type rearrangement. The reaction proceeds with almost equal facility with substrates having either electron-donating or electron-withdrawing substituent. Similarly, α,?-unsaturated, and sterically hindered ortho-substituted hydroxamates also undergo the desired transformation smoothly.
- Ghosh, Subhankar,Banerjee, Jeet,Ghosh, Rajat,Chattopadhyay, Shital K.
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p. 1353 - 1360
(2020/03/30)
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- Palladium-Catalyzed Carbonylative Synthesis of Benzyl Benzoates Employing Benzyl Formates as Both CO Surrogates and Benzyl Alcohol Sources
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An efficient and convenient palladium-catalyzed carbonylation reaction for the synthesis of benzyl benzoates from aryl bromides has been developed. Benzyl formates have been explored as a new type of efficient and useful CO sources and also reaction partners. A wide range of benzyl benzoates was obtained in good to excellent yields.
- Lai, Ming,Qi, Xinxin,Wu, Xiao-Feng
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supporting information
p. 3776 - 3778
(2019/06/24)
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- Pyridinium oxidations of benzyl alcohol under microwave-assisted retro-ene conditions
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Benzyl alcohol is oxidized to benzaldehyde when heated in sulfolane in the presence of N-benzylnicotinamide and N-benzylpyridinium salts. The oxidation is accelerated in the presence microwaves. Oxidations with related pyridiniums suggest that these oxidations could occur via retro-ene reactions.
- Jensen, Anton W.,Moore, John M.,Kimble, MaryEllen V.,Ausmus, Alex P.,Dilling, Wendell L.
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supporting information
p. 5636 - 5638
(2016/11/28)
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- NOVEL SINGLE STEP ESTERIFICATION PROCESS OF ALDEHYDES USING A HETEROGENEOUS CATALYST
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The present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using a heterogeneous catalyst with high yields. More particularly, the present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using Titanium superoxide with greater than 80% yields.
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Page/Page column 9; 15
(2016/06/20)
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- Titanium superoxide-a stable recyclable heterogeneous catalyst for oxidative esterification of aldehydes with alkylarenes or alcohols using TBHP as an oxidant
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Titanium superoxide efficiently catalysed the oxidative esterification of aldehydes with alkylarenes or alcohols, under truly heterogeneous conditions, to afford the corresponding benzyl and alkyl esters in excellent yields. Mechanistic studies have established that this "one pot" direct oxidative esterification process proceeds through a radical pathway, proven by a FTIR spectral study of a titanium superoxide-aldehyde complex as well as spin trapping experiments with TEMPO. The intramolecular version of this protocol has been successfully demonstrated in the concise synthesis of 3-butylphthalide, an anti-convulsant drug.
- Dey, Soumen,Gadakh, Sunita K.,Sudalai
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p. 10631 - 10640
(2015/11/17)
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- N-Heterocyclic Carbene-Mediated Oxidative Electrosynthesis of Esters in a Microflow Cell
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An efficient N-heterocyclic carbene (NHC)-mediated oxidative esterification of aldehydes has been achieved in an undivided microfluidic electrolysis cell at ambient temperature. Productivities of up to 4.3 g h-1 in a single pass are demonstrated, with excellent yields and conversions for 19 examples presented. Notably, the oxidative acylation reactions were shown to proceed with a 1:1 stoichiometry of aldehyde and alcohol (for primary alcohols), with remarkably short residence times in the electrolysis cell (13 s), and without added electrolyte. (Chemical Equation Presented).
- Green, Robert A.,Pletcher, Derek,Leach, Stuart G.,Brown, Richard C. D.
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supporting information
p. 3290 - 3293
(2015/07/15)
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- Ester manufacturing method (by machine translation)
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PROBLEM TO BE SOLVED: To produce an ester compound by transesterification using an inexpensive and low toxic inorganic compound. SOLUTION: Transesterification of an ester compound and an alcohol compound is carried out under the presence of lanthanum nitrate (for example, lanthanum nitrate hexahydrate) and a phosphine compound (for example, tri-n-octylphosphine), thereby obtaining the ester product. For example, transesterification of dimethyl carbonate and benzyl alcohol is carried out under the presence of 1 mol% of lanthanum nitrate hexahydrate, and 2 mol% of tri-n-octylphosphine, thereby obtaining benzyl methylcarbonate at a yield of >99%. COPYRIGHT: (C)2012,JPO&INPIT
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Paragraph 0054; 0055; 0056
(2017/02/17)
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- Electrogenerated N-heterocyclic carbenes in the room temperature parent ionic liquid as an efficient medium for transesterification/acylation reactions
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N-Heterocyclic carbenes (NHCs), generated by electrochemical reduction under galvanostatic control of 1,3-dialkylimidazolium-based ionic liquids, were employed as catalysts in transesterification reactions in the parent, room temperature ionic liquids (RTILs) as solvents, without the utilisation of any volatile organic solvent or base. The reaction between isopropenyl or ethyl acetate and an alcohol (not efficient in the absence of catalyst) was induced by the presence of an electrogenerated NHC, which seems to assist the proton transfer from the alcohol to the ester, yielding the corresponding acetate. The reaction also proceeds with methyl nicotinate as starting ester and 2-(diethylamino)ethanol or benzyl alcohol as alcohols and leads to the corresponding biologically active compounds, nicametate and benzyl nicotinate, in good yields. All products were isolated in good to excellent yields and complete recyclability of the ionic liquid as solvent has been demonstrated.
- Chiarotto, Isabella,Feroci, Marta,Sotgiu, Giovanni,Inesi, Achille
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supporting information
p. 326 - 331
(2013/02/25)
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- CeO2-catalysed one-pot selective synthesis of esters from nitriles and alcohols
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Thirteen kinds of metal oxides were tested for one-pot selective synthesis of esters from nitriles and alcohols. Ceria (CeO2) showed more than two orders of magnitude higher activity than the other oxides. CeO2 acted as a reusable and effective catalyst for the ester synthesis from various nitriles and alcohols under neutral and solvent-free conditions at 160 °C. This method provides a rare example for the synthesis of heteroaromatic esters, which have been difficult to synthesize by conventional catalytic esterification methods. Valuable esters such as picolinic acid alkyl esters and niacin benzyl esters were synthesized, demonstrating a practical aspect of the present method. Kinetic studies suggested the following reaction mechanism: (1) H2O and ROH dissociate on CeO2, (2) nucleophilic attack of hydroxyl species (OHδ-) to the adsorbed nitrile on CeO2, leading to the formation of the primary amide, (3) nucleophilic attack of alkoxide species (ORδ-) to the amide as the rate-limiting step.
- Tamura, Masazumi,Tonomura, Takuya,Shimizu, Ken-Ichi,Satsuma, Atsushi
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supporting information; experimental part
p. 984 - 991
(2012/06/18)
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- In situ generated "lanthanum(iii) nitrate alkoxide" as a highly active and nearly neutral transesterification catalyst
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In situ generated lanthanum(iii) nitrate alkoxide is a highly active and nearly neutral transesterification catalyst, which can promote non-epimerized transesterification of α-substituted chiral carboxylic esters under reflux conditions.
- Hatano, Manabu,Kamiya, Sho,Ishihara, Kazuaki
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supporting information
p. 9465 - 9467
(2012/10/29)
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- A method for the reductive scission of heterocyclic thioethers
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A mild, chemoselective, and generally high-yielding method for the reductive scission of heterocyclic thioethers is described. Suitable heterocycles have a thioether substituent at the 2-position relative to a ring heteroatom. The convenient and straightforward method is demonstrated with reactants which are not compatible with the standard Raney nickel conditions such as sulfides, sulfones, and thiophenes. In addition, benzyl esters, benzyl amides, and benzyl carbamates are tolerated by the reductive reaction conditions.
- Graham, Thomas H.,Liu, Wensheng,Shen, Dong-Ming
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supporting information; experimental part
p. 6232 - 6235
(2012/01/03)
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- A rapid and facile esterification of na-carboxylates with alkyl halides promoted by the synergy of the combined use of DMSO and an ionic liquid under ambient conditions
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The synergy of the combined use of DMSO and an ionic liquid viz. (bbim) has brought about a rapid and efficient esterification of sodium carboxylates with acyl and alkyl halides under ambient conditions in excellent isolated yields (90-95%) in short reaction times (12-40min). Copyright Taylor & Francis Group, LLC.
- Dighe, Satish N.,Bhattad, Ravindra V.,Kulkarni, Raghunath R.,Jain, Kishor S.,Srinivasan, Kumar V.
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experimental part
p. 3522 - 3527
(2011/02/22)
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- New reagents for the synthesis of arylmethyl ethers and esters
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This Account chronicles efforts leading up to the development of new arylmethyl transfer (benzylation) reagents for protecting oxygen functional groups under relatively mild and neutral conditions. It begins with an investigation of organosiletanes as surrogate hydroxyl groups, which inspired siletane-functionalized benzyl ethers and forced us to confront the difficulties associated with the synthesis of benzyl ethers. The end result is a new series of neutral oxypyridinium salts for the benzylation of various nucleophilic functional groups under mild conditions. 1 Introduction 2 Tamao-type Oxidation of Strained Organosiletanes 3 p-Siletanylbenzyl (PSB) Protecting Groups 4 2-Benzyloxy-1-methylpyridinium Triflate 5 Friedel-Crafts Reactions and Mechanistic Insights 6 Benzyl Ester Formation 7 Substituted Benzyl Transfer Reagents 8 Conclusions and Outlook. Georg Thieme Verlag Stuttgart New York.
- Albiniak, Philip A.,Dudley, Gregory B.
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scheme or table
p. 841 - 851
(2010/07/10)
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- Carbonylation of aryl chlorides with oxygen nucleophiles at atmospheric pressure. Preparation of phenyl esters as acyl transfer agents and the direct preparation of alkyl esters and carboxylic acids
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(Chemical Equation Presented) A mild, functional group tolerant method of the preparation of phenyl esters from aryl chlorides via palladium-catalyzed carbonylation is described using atmospheric pressure of carbon monoxide. Phenyl esters are shown to be useful acylating agents, delivering libraries of carbonyl derivatives, including alkyl, allyl and thioesters, under very mild conditions. Direct preparation of alkyl esters and carboxylic acids is also demonstrated, providing the first method for the preparation of methyl and ethyl esters from aryl chlorides without pressured reactors.
- Watson, Donald A.,Fan, Xuexiang,Buchwald, Stephen L.
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supporting information; experimental part
p. 7096 - 7101
(2009/05/09)
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- A simple procedure for the esterification of alcohols with sodium carboxylate salts using 1-tosylimidazole (TsIm)
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An efficient and selective method for esterification of alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, alcohols are refluxed with a mixture of RCO2Na (R: alkyl and aryl), TsIm, and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in DMF to afford the corresponding esters in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°.
- Soltani Rad, Mohammad Navid,Behrouz, Somayeh,Faghihi, Mohammad Ali,Khalafi-Nezhad, Ali
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p. 1115 - 1120
(2008/09/17)
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- Zwitterionic salts as mild organocatalysts for transesterification
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(Chemical Equation Presented) The exothermic reaction of 3,5-bis(trifluoromethyl)phenyl or 4-nitrophenyl isothiocyanate with 4-pyrrolidinopyridine (PPY) gave the corresponding arylaminothiocarbonylpyridinium salts in quantitative yields. These novel zwitterionic salts were effective as organocatalysts for the transesterification reaction of an equimolar mixture of methyl carboxylates and alcohols in hydrocarbons such as heptane and octane under azeotropic reflux conditions with the removal of methanol. In sharp contrast, PPY was inert as a catalyst under the same reaction conditions.
- Ishihara, Kazuaki,Niwa, Masatoshi,Kosugi, Yuji
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supporting information; experimental part
p. 2187 - 2190
(2009/05/27)
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- Synthesis of benzyl esters using 2-benzyloxy-1-methylpyridinium triflate
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(Chemical Equation Presented) Triethylamine (Et3N) mediates esterification reactions between the title reagent (1) and carboxylic acids. Alcohols, phenols, amides, and other sensitive functionality are not affected; a dual role for Et3N as a promoter and a scavenger is postulated. Benzyl esters are obtained from substrates including amino acid and sugar derivatives.
- Tummatorn, Jumreang,Albiniak, Philip A.,Dudley, Gregory B.
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p. 8962 - 8964
(2008/03/12)
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- A Convenient Protocol for the Esterification of Carboxylic Acids with Alcohols in the Presence of di-t-Butyl Dicarbonate
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Stoichiometric mixtures of carboxylic acids and primary or secondary alkyl alcohols are cleanly converted into their corresponding esters by treatment with di-t-butyl dicarbonate [(BOC)2O] in the presence of catalytic amounts of N,N′-dimethylaminopyridine (DMAP). This convenient procedure provides a general access to a broad variety of esters including those bearing highly sensitive functional groups such as phenol esters or BOC-groups. Purification of the products is particularly easy since the byproducts t-BuOH and CO2 are volatile - a great advantage over the standard DCC/DMAP method.
- Goo?en, Lukas J.,D?hring, Arno
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p. 263 - 266
(2007/10/03)
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- An expedient esterification of aromatic carboxylic acids using sodium bromate and sodium hydrogen sulfite
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Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters.
- Khan, Khalid Mohammed,Maharvi, Ghulam Murtaza,Hayat, Safdar,Zia-Ullah,Choudhary, M. Iqbal,Atta-ur-Rahman
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p. 5549 - 5554
(2007/10/03)
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- Efficient transesterification/acylation reactions mediated by N-heterocyclic carbene catalysts
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Imidazol-2-ylidenes, a family of N-heterocyclic carbenes (NHC), are efficient catalysts in the transesterification involving numerous esters and alcohols. Low catalyst loadings of aryl- or alkyl-substituted NHC catalysts mediate the acylation of alcohols with enol acetates in short reaction times at room temperature. Commercially available and more difficult to cleave methyl esters react with primary alcohols in the presence of alkyl-substituted NHC to efficiently form the corresponding esters. While primary alcohols are selectively acylated over secondary alcohols with use of enol esters as acylating agents, methyl and ethyl esters can be employed as protective agents for secondary alcohols in the presence of the more active alkyl-substituted NHC catalysts. The NHC-catalyzed transesterification protocol was simplified by generating the imidazol-2-ylidene catalysts in situ.
- Grasa, Gabriela A.,Gueveli, Tatyana,Singh, Rohit,Nolan, Steven P.
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p. 2812 - 2819
(2007/10/03)
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- Lewis Acids as Highly Efficient Catalysts for the Decarboxylative Esterification of Carboxylic Acids with Dialkyl Dicarbonates
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Mild Lewis acids such as Mg(ClO4)2 show a new level of catalytic activity for the decarboxylative esterification of carboxylic acids with commercially available dialkyl dicarbonates. In the presence of as little as one mol % Mg(ClO4)2 catalyst, carboxylic acids can thus easily and near quantitatively be protected at room temperature, e.g., as methyl, benzyl, or t-butyl esters. Only volatile by-products are released so that the purification of the products is particularly easy. Many sensitive functionalities are tolerated, including even phenol esters, or free hydroxy and BOC groups.
- Goossen,Doehring
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p. 943 - 947
(2007/10/03)
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- Esterification of carboxylic acid salts
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Mono- or polycarboxylic acid esters are prepared by reacting a salt of such carboxylic acid with an organic halocompound, e.g., a (cyclo)alkyl, (cyclo)alkenyl, aryl or aralkyl halide, in an aqueous reaction medium, in the presence of a catalytically effective amount of a phase transfer catalyst, for example an onium salt.
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- Cosmetic composition
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Compositions containing an ester of nicotinic acid and a cosmetically acceptable surfactant are provided. These compositions, when applied topically to the human body produce a response such as a sensory or therapeutic response, for example a tingling or warming sensation or an increase in blood flow, which persists after the composition is rinsed from the body. The compositions are particularly suitable for application to the hair and/or scalp where they may encourage hair growth. Compositions for application to the hair and/or scalp preferably additionally comprise hair benefit agents such as hair growth promoters.
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- The Use of a Nicotinoyl Group as a Protective Group for Hydroxyl and Amino Functions
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The effective use of a nicotinoyl group as an easily introducible and cleavable protective group for hydroxyl and amino groups is described.Deprotection by alkaline hydrolysis is performed after activation by quarternization of pyridine moiety with methyl iodide.
- Ushida, Satoshi
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- CONVENIENT SYNTHESIS OF ESTERS OF 2-PYRROLECARBOXYLIC ACID AND OF PYRIDINECARBOXYLIC ACIDS BY SOLID-LIQUID PHASE TRANSFER CATALYSIS WITHOUT ADDED SOLVENT
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By reaction of aromatic K-carboxylates having nucleophilic N-atom in solid-liquid phase transfer catalysis (PTC) conditions without added solvent (catalyst : tetraalkylammonium halide) with alkylating reagents, the corresponding esters are prepared.By a judicious choice of experimental conditions, the amounts of N-alkylated products can be lowered.From 2-pyrrolecarboxylic acid, the three isomers of pyridinecarboxylic acid and o-aminobenzoic acid, corresponding esters of ethyl, benzyl, n-octyl and n-cetyl, generally are obtained with good yields.
- Barry, Jean,Bram, Georges,Petit, Alain
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p. 875 - 880
(2007/10/02)
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