- Ru/SiO2 Catalyst for Highly Selective Hydrogenation of Dimethyl Malate to 1,2,4-Butanetriol at Low Temperatures in Aqueous Solvent
-
Catalytic selective hydrogenation of esterified malic acid to produce 1,2,4-butanetriol (1,2,4-BT) using H2 as the reducing reagent suffers from the low 1,2,4-BT selectivity. Here, Ru/SiO2 catalyst was employed for selective hydrogenation of dimethyl malate (DM) to produce 1,2,4-BT, which gave abnormal high DM conversion (100%) and 1,2,4-BT selectivity (92.4%) in aqueous solvent at 363?K, especially, the 1,2,4-BT yield even is higher than the optimal catalyst reported (Ru-Re, 79.8%). The reaction pathways for the DM hydrogenation on Ru/SiO2 were also proposed, suggesting that extremely high 1,2,4-BT selectivity require for the much high hydrogenation rates at low temperatures, where side-reaction transesterification rates are relatively low. The extremely high hydrogenation activity and 1,2,4-BT selectivity on Ru/SiO2 in aqueous solvent at low temperatures arise from that H2O may coordinate to Ru2+ and prevent the reduction of Ru2+ to Ru under high H2 pressure. Ru/SiO2 surface presents abundant Ru2+ in aqueous solvent, can activate H2 through heterolytic cleavage mode to form hydride, which can significantly increase hydrogenation rates of C = O groups at low temperatures. In addition, the activity and 1,2,4-BT selectivity on Ru/SiO2 catalyst only reduced by 2.3% and 2.6%, respectively over a period of 550?h. Graphical Abstract: [Figure not available: see fulltext.]
- Chen, Can,Jiang, Junxiang,Li, Guangci,Li, Xuebing,Wang, Da,Wang, Zhong,Yu, Pei
-
-
- A Concise Stereoselective Total Synthesis of Methoxyl Citreochlorols and Their Structural Revisions
-
A concise, stereoselective and protecting group free approaches for the total synthesis of (?)-(2S,4R)- and (+)-(2R,4S)-3′-methoxyl citreochlorols and their stereoisomers are demonstrated. All four stereoisomers were synthesized to establish the absolute stereochemistry of the reported structures and the structures were revised accordingly. The approach involves chelation controlled regioselective reduction of a diester, silyl iodide promoted ring-opening iodo esterification of lactones, highly chemo- and regioselective ring-opening of an epoxy ester, dichloromethylation of a carboxyl group, and syn- and anti-selective reduction of the resulted β-hydroxy ketone as key steps.
- Sunnapu, Ranganayakulu,Rajendar, Goreti
-
p. 1637 - 1642
(2021/03/15)
-
- Synthesis of nature product kinsenoside analogues with anti-inflammatory activity
-
Kinsenoside is the major bioactive component from herbal medicine with a broad range of pharmacological functions. Goodyeroside A, an epimer of kinsenoside, remains less explored. In this report we chemically synthesized kinsenoside, goodyeroside A and their analogues with glycan variation, chirality inversion at chiral center(s), and bioisosteric replacement of lactone with lactam. Among these compounds, goodyeroside A and its mannosyl counterpart demonstrated superior anti-inflammatory efficacy. Furthermore, goodyeroside A was found to suppresses inflammatory through inhibiting NF-κB signal pathway, effectively. Structure-activity relationship is also explored for further development of more promising kinsenoside analogues as drug candidates.
- Song, Wei,Sun, Yong,Xu, Lintao,Sun, Yajing,Li, Tianlu,Peng, Peng,Lou, Hongxiang
-
supporting information
(2020/12/02)
-
- Synthesis method of R-3-propyl-gamma-butyrolactone
-
The invention discloses a synthetic method of R-3-propyl-gamma-butyrolactone, and belongs to the technical field of organic synthesis. The method comprises the following steps: by taking D-malic acidas a raw material, performing monomethyl esterification, reduction, halogenation or sulfonic acid esterification, and finally coupling with a Grignard reagent under the catalysis of zinc chloride to obtain a brivaracetam intermediate that is the R-3-propyl-gamma-butyrolactone. The method has the advantages of cheap and easily available starting raw materials, good stereoselectivity, no need of chiral resolution, mild condition, short route and the like, and provides a feasible scheme for brivaracetam process research.
- -
-
Paragraph 0042; 0045-0048
(2020/07/12)
-
- Intercepted dehomologation of aldoses by N-heterocyclic carbene catalysis-a novel transformation in carbohydrate chemistry
-
The development of an N-heterocyclic carbene (NHC) catalysed intercepted dehomologation of aldoses is reported. The unique selectivity of NHCs for aldehydes is exploited in the complex context of reducing sugars. Examples of strong substrate governance for either intercepted dehomologation or a subsequent redox-lactonisation were identified and mechanistically understood. More importantly, it was shown that catalyst design allowed the tuning of the selectivity of the reaction with structurally unbiased starting materials towards either of the two scenarios.
- Draskovits, Markus,Kalaus, Hubert,Stanetty, Christian,Mihovilovic, Marko D.
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p. 12144 - 12147
(2019/10/21)
-
- Practical Cleavage of Acetals by Using an Odorless Thiol Immobilized on Silica
-
A practical, efficient and general method was developed for the deprotection of a variety of aromatic and aliphatic acetals to their corresponding catechol or diol derivatives using thiol immobilized on silica gel. This is an application for the well-known commercial solid-supported thiol (SiliaMetS Thiol). The procedure is mild and amenable to scale-up. It does not require inert atmosphere and clean conversions were observed. This method is applicable to substituted 1,3-benzodioxole and aliphatic acetals with different functionalities. It offers the advantage of a general route with high yield, which can be undertaken at ambient temperature.
- de Léséleuc, Mylène,Kukor, Andrew,Abbott, Shaun D.,Zacharie, Boulos
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p. 7389 - 7393
(2019/12/03)
-
- Total synthesis and stereochemical assignment of nostosin B
-
Nostosins A and B were isolated from a hydrophilic extract of Nostoc sp. strain from Iran, which exhibits excellent trypsin inhibitory activity. Nostosin A was the most potent natural tripeptide aldehyde as trypsin inhibitor up to now. Both R- and S-2-hydroxy-4-(4-hydroxy-phenyl)butanoic acid (Hhpba) were prepared and incorporated into the total synthesis of nostosin B, respectively. Careful comparison of the NMR spectra and optical rotation data of synthetic nostosin B (1a and 1b) with the natural product led to the unambiguous identification of the R-configuration of the Hhpba fragment, which was further confirmed by co-injection with the authentic sample on HPLC using both reversed phase column and the chiral AD-RH column.
- Wang, Xiaoji,Feng, Junmin,Xu, Zhengshuang,Ye, Tao,Meng, Yi,Zhang, Zhiyu
-
-
- A high selective (S)-β-hydroxy-γ-butyrolactone simple method for preparing
-
The invention relates to a simple and convenient preparation method of highly selective (S)-beta-hydroxy-gamma-butyrolactone. The simple and convenient preparation method comprises the following steps: with allyl alcohol as a starting material, preparing (R)-2, 3-epoxy propanol by virtue of asymmetric epoxidation, and carrying out cyanidation, cyan-hydrolysis and esterification on (R)-2, 3-epoxy propanol to prepare the (S)-beta-hydroxy-gamma-butyrolactone. The simple and convenient preparation method is short in reaction route, easily available in raw material, easy in reaction condition operation, high in reaction selectivity and suitable for industrial production.
- -
-
Paragraph 0048; 0052; 0053; 0058; 0059; 0063; 0064; 0065
(2019/02/04)
-
- Study of Class i and Class III Polyhydroxyalkanoate (PHA) Synthases with Substrates Containing a Modified Side Chain
-
Polyhydroxyalkanoates (PHAs) are carbon and energy storage polymers produced by a variety of microbial organisms under nutrient-limited conditions. They have been considered as an environmentally friendly alternative to oil-based plastics due to their renewability, versatility, and biodegradability. PHA synthase (PhaC) plays a central role in PHA biosynthesis, in which its activity and substrate specificity are major factors in determining the productivity and properties of the produced polymers. However, the effects of modifying the substrate side chain are not well understood because of the difficulty to accessing the desired analogues. In this report, a series of 3-(R)-hydroxyacyl coenzyme A (HACoA) analogues were synthesized and tested with class I synthases from Chromobacterium sp. USM2 (PhaCCs and A479S-PhaCCs) and Caulobacter crescentus (PhaCCc) as well as class III synthase from Allochromatium vinosum (PhaECAv). It was found that, while different PHA synthases displayed distinct preference with regard to the length of the alkyl side chains, they could withstand moderate side chain modifications such as terminal unsaturated bonds and the azide group. Specifically, the specific activity of PhaCCs toward propynyl analogue (HHxyCoA) was only 5-fold less than that toward the classical substrate HBCoA. The catalytic efficiency (kcat/Km) of PhaECAv toward azide analogue (HABCoA) was determined to be 2.86 × 105 M-1 s-1, which was 6.2% of the value of HBCoA (4.62 × 106 M-1 s-1) measured in the presence of bovine serum albumin (BSA). These side chain modifications may be employed to introduce new material functions to PHAs as well as to study PHA biogenesis via click-chemistry, in which the latter remains unknown and is important for metabolic engineering to produce PHAs economically.
- Jia, Kaimin,Cao, Ruikai,Hua, Duy H.,Li, Ping
-
p. 1477 - 1485
(2016/05/09)
-
- Development of Noviomimetics as C-Terminal Hsp90 Inhibitors
-
KU-32 and KU-596 are novobiocin-derived, C-terminal heat shock protein 90 (Hsp90) modulators that induce Hsp70 levels and manifest neuroprotective activity. However, the synthetically complex noviose sugar requires 10 steps to prepare, which makes translational development difficult. In this study, we developed a series of "noviomimetic" analogues of KU-596, which contain noviose surrogates that can be easily prepared, while maintaining the ability to induce Hsp70 levels. Both sugar and sugar analogues were designed, synthesized, and evaluated in a luciferase reporter assay, which identified compound 37, a benzyl containing noviomimetic, as the most potent inducer of Hsp70.
- Anyika, Mercy,McMullen, Mason,Forsberg, Leah K.,Dobrowsky, Rick T.,Blagg, Brian S. J.
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supporting information
p. 67 - 71
(2016/02/03)
-
- Microbial production of 3,4-dihydroxybutyrate (3,4-DHBA), 2,3-dihydroxybutyrate (2,3-DHBA) and 3-hydroxybutyrolactone (3-HBL)
-
The invention relates to recombinant cells and their use in the production of 3,4-dihydroxybutyrate, 2,3-dihydroxybutyrate and 3-hydroxybutyrolactone.
- -
-
Page/Page column 32
(2014/03/25)
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- Efficient synthesis of kinsenoside and goodyeroside A by a chemo-enzymatic approach
-
Kinsenoside (1) and goodyeroside A (2), two naturally occurring stereoisomers with diverse biological activities, have been synthesized efficiently by a chemo-enzymatic approach with a total yield of 12.7%. The aglycones, (R)- and (S)-3-hydroxy-γ-butyrolactone, were prepared from D- and L-malic acid by a four-step chemical approach with a yield of 75%, respectively. These butyrolactones were then successfully glycosidated using β-D-glucosidase as a catalyst in a homogeneous organic-water system. Under the optimized enzymatic conditions, the yields of kinsenoside and goodyeroside A in the enzymatic steps both reached 16.8%.
- Zhang, Yang,Xia, Yihong,Lai, Yongji,Tang, Fang,Luo, Zengwei,Xue, Yongbo,Yao, Guangmin,Zhang, Yonghui,Zhang, Jinwen
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p. 16950 - 16958
(2015/01/08)
-
- New polyesters from Talaromyces flavus
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Six new polyesters, talapolyesters A-F (1-4, 14, and 16), together with 11 known ones 15G256ν (5), 15G256ν-me (6), 15G256π (7), 15G256β-2 (8), 15G256α-2 (9), 15G256α-2-me (10), 15G256ι (11), 15G256β (12), 15G256α (13), 15G256α-1 (15), and 15G256ω (17), were isolated from the wetland soil-derived fungus Talaromyces flavus BYD07-13, and their structures were determined by NMR and MS spectroscopic data. Among them, 1-4 and 16 were assembled in a different manner from that of the known 256 polyesters. All the polyesters are composed of (R)-2,4-dihydroxy-6-(2- hydroxypropyl)benzoic acid and (R)-3-hydroxybutyric acid/(S)-3,4- dihydroxybutyric acid residues. The absolute configurations of the residues were determined by alkaline hydrolysis. The cytotoxicity against five tumor cell lines of these compounds was examined, and a tight structure-activity relationship is proposed.
- He, Jun-Wei,Mu, Zhen-Qiang,Gao, Hao,Chen, Guo-Dong,Zhao, Qin,Hu, Dan,Sun, Jing-Zu,Li, Xiao-Xia,Li, Yan,Liu, Xing-Zhong,Yao, Xin-Sheng
-
p. 4425 - 4430
(2014/06/10)
-
- A novel derivatization procedure and chiral gas chromatographic method for enantiomeric purity screening of L-carnitine
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L-Carnitine is used extensively in functional foods and food supplements; consequently, the control of its enantiomeric purity is of paramount importance. A new derivatization procedure and chiral gas chromatographic method with flame ionization detection, using a cyclodextrin based stationary phase, enables prompt, simple, and inexpensive screening of the enantiomeric ratio of L- and D-carnitine in samples with different matrices. Conversion of carnitine to β-acetoxy-γ- butyrolactone was optimized for maximum conversion (98% of the desired product lactone was formed and 2% of the side product γ-crotonolactone) and minimum racemization (no changes at the chiral center were detected) and time consumption. As it is shown in this study, a fast gas chromatographic method, with total run time of 7 min, together with the new derivatization procedure enables an effective enantiomeric purity screening of L-carnitine in real samples such as food supplements and L-carnitine raw ingredient.
- Albreht, Alen,Zupani, Borut,Vovk, Irena
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p. 889 - 893
(2015/02/05)
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- Asymmetric cycloetherifications by bifunctional aminothiourea catalysts: The importance of hydrogen bonding
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Chiral oxacyclic frameworks are prevalent in many natural products and bioactive compounds. In addition, a number of them are important synthetic intermediates. Thus, the synthesis of such structures is a significant goal in the field of organic chemistry. However, the development of catalytic asymmetric cycloetherification for the straightforward synthesis of these compounds remains a challenge. In this study, we propose the use of aminothiourea catalysis as an effective way to accomplish such a challenge. The asymmetric synthesis of chiral oxygen heterocycles, including tetrahydrofurans, tetrahydropyrans, and 1,3-dioxolanes, is demonstrated herein using intramolecular oxy-Michael addition mediated by bifunctional aminothiourea catalysts. Georg Thieme Verlag Stuttgart · New York.
- Fukata, Yukihiro,Miyaji, Ryota,Okamura, Takaaki,Asano, Keisuke,Matsubara, Seijiro
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p. 1627 - 1634
(2013/07/27)
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- Organocatalytic asymmetric oxy-Michael addition to a γ-hydroxy- α,β-unsaturated thioester via hemiacetal intermediates
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We report an asymmetric oxy-Michael addition to a γ-hydroxy-α, β-unsaturated thioester via hemiacetal intermediates in the presence of Cinchona-alkaloid-thiourea-based bifunctional organocatalysts. This method provides a novel enantioselective route to β-hydroxy carboxyl compounds, which in turn can be used to synthesize valuable chiral building blocks.
- Okamura, Takaaki,Asano, Keisuke,Matsubara, Seijiro
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supporting information; experimental part
p. 5076 - 5078
(2012/07/02)
-
- Ru-catalyzed asymmetric hydrogenation of γ-heteroatom substituted β-keto esters
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A series of enantiomerically pure γ-heteroatom substituted β-hydroxy esters were synthesized with high enantioselectivities (up to 99.1% ee) by hydrogenation of γ-heteroatom substituted β-keto esters in the presence of Ru-(S)-SunPhos catalyst. These asymmetric hydrogenations provide key building blocks for a variety of naturally occurring and biologically active compounds.
- Fan, Weizheng,Li, Wanfang,Ma, Xin,Tao, Xiaoming,Li, Xiaoming,Yao, Ying,Xie, Xiaomin,Zhang, Zhaoguo
-
experimental part
p. 9444 - 9451
(2012/01/13)
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- Structure elucidation and stereoselective total synthesis of pavettamine, the causal agent of gousiekte
-
The structure elucidation of a novel natural product pavettamine (1), the causal agent of the plant toxicosis gousiekte, is reported. The structure was defined by analysis of NMR and MS data and the relative configuration followed from the 13C NMR data of the acetonide derivative. The absolute stereochemistry was established by total synthesis from (2S)-malic acid using chiral sulfoxide methodology as (2S,4R,8R,10S)-1,11-diamino-6-aza-undecane-2,4,8,10-tetraol.
- Bode, Moira L.,Gates, Paul J.,Gebretnsae, Samson Y.,Vleggaar, Robert
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supporting information; experimental part
p. 2026 - 2036
(2010/04/26)
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- METHOD FOR PREPARING (S)-3-HYDROXY-GAMMA-BUTYROLACTONE USING HYDROLASE
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The present invention relates to a method for preparing S-HGB ((S)-3-hydroxy-γ-butyrolactone) using hydrolase, and more particularly to a method for preparing S-HGB in a high purity by hydrolyzing S-BBL ((S)-β-benzoyloxy-γ-butyrolactone) in the presence of hydrolase. According to the present invention, the S-HGB having an optical purity can be obtained in a high yield under simple process conditions without requiring reaction conditions of high pressure and high temperature or complex operation conditions by hydrolyzing S-BBL with hydrolase.
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Page/Page column 7-8
(2008/06/13)
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- THE METHOD OF MAKING OPTICALLY ACTIVE 3-ACYLOXY-GAMMA-BUTYROLACTONE AND OPTICALLY ACTIVE 3-HYDROXY-GAMMA-BUTYROLACTONE BY ENZYMATIC METHOD
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The present invention relates to the process for preparing optically active 3-acyloxy-gamma-butyrolactone repesented by the general formula 5 and optically active 3-hydroxy-gamma-butyrolactone represented by the general formula 6 in scheme 1 from racemic 3-acyloxy-gamma-butyrolactone repesented by the general formula 4 by enzymatic method. In more detail, this invention relates to the process for the preparation of optically active 3-acyloxy-gamma-butyrolactone and optically active 3-hydroxy-gamma-butyrolactone wherein racemic epichlorohydrin represented by the general formula 1 is subjected to produce racemic 4-chloro-3-hydroxybutyronitrile, racemic 3-hydroxy-gamma-butyrolactone and racemic 3-acyloxy-gamma-butyrolactone in turn and racemic 3-acyloxy-gamma-butyrolactone is hydrolyzed sterospecifically using lipases or lipase-producing microorganisms in the aqeous phase or organic phase containing water. This method is useful in the practical process because production and seperation of compounds with high optical purity are easy comparing with other reported process.
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Page/Page column 6
(2008/06/13)
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- A PROCESS FOR THE SYNTHESIS OF 3-HYDROXY-GAMMA-BUTYROLACTONE
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The present invention relates to a process for preparing pure 3-hydroxy-γ-butyrolactone by hydrolyzing 4-chloro-3-hydroxy-butyronitrile in the presence of acids and conducting cyclization reaction under slightly basic condition.
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-
Page/Page column 5-6
(2008/06/13)
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- Dirhodium(II) tetrakis[N-benzene-fused phthaloyl-(S)-piperidinonate] as a chiral lewis acid: Catalytic enantioselective aldol reactions of acetate-derived silylketene acetals and aldehydes
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A first example of chiral dirhodium(II) complex-catalyzed enantioselective Mukaiyama aldol reactions is described. The aldol addition reaction of methyl acetate-derived trimethylsilylketene acetal with specific aldehydes such as benzyloxyacetaldehyde and electron-poor aromatic aldehydes is effectively catalyzed by dirhodium(II) tetrakis[N-benzene-fused phthaloyl-(S)-piperidinonate] (1a), providing silylated aldol adducts in up to 94% ee.
- Washio, Takuya,Nakamura, Seiichi,Anada, Masahiro,Hashimoto, Shunichi
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p. 567 - 578
(2007/10/03)
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- A simple and practical approach to enantiomerically pure (S)-3-hydroxy-γ-butyrolactone: Synthesis of (R)-4-cyano-3-hydroxybutyric acid ethyl ester
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The oxidation of α- or β-(1,4) linked disaccharides or oligosaccharides with cumene hydroperoxide in the presence of a base gave (S)-3,4-dihydroxybutyric acid, which was cyclized under acidic conditions to furnish (S)-3-hydroxy-γ-butyrolactone. This was subsequently converted into (R)-cyano-3-hydroxybutyric acid ethyl ester, an intermediate for statin based drugs and other related compounds.
- Kumar, Pradeep,Deshmukh, Anis N.,Upadhyay, Rajesh K.,Gurjar, Mukund K.
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p. 2717 - 2721
(2007/10/03)
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- Synthesis of mono- and dihydroxylated furanoses, pyranoses, and an oxepanose for the preparation of natural product analogue libraries
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Numerous biologically active natural products contain furanoses and pyranoses with mono- and dihydroxylated substituents. However, much of the structure-activity studies on such molecules is gathered on the aglycons without attention to the corresponding carbohydrate components. Consequently, there are few synthetic procedures that enable the rapid preparation of mono- and dihydroxyfuranoses and mono- and dihydroxypyranoses and no report for a 3,4-dihydroxyoxepanose. In this article we report the practical synthesis of orthogonally protected five-, six-, and seven-membered carbohydrate derivatives. The succinct manner in which these molecules were synthesized allows the rapid preparation of analogues aimed at discovering the role of ring size and individual hydroxyl moieties on the pyranose skeleton.
- Yu, Xiao Ming,Han, Huijong,Blagg, Brian S. J.
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p. 5599 - 5605
(2007/10/03)
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- Lycoperdinoside A and B, new glycosides from the slime mold Enteridium lycoperdon
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Two, novel, six-membered lactone glycosides (lycoperdinoside A and B) were isolated from the slime mold Enteridium lycoperdon. Their structures, including the absolute configurations of the hydroxy and methyl groups, were determined by means of extensive spectroscopic data such as MS, IR, UV, and ID and 2D NMR spectra and chemical degradation. The compounds have structures containing a β-L-amicetosyl-(1→4)-α-l-amicetosyl unit and a β-L-amicetosyl-(1→4)-α-L-amicetosyl-(1→4) -β-L-rhodinosyl unit, respectively. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Rezanka, Tomas,Dvorakova, Radmila,Hanus, Lumir O.,Dembitsky, Valery M.
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p. 995 - 1001
(2007/10/03)
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- PROCESS FOR PRODUCING LACTONE
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A method for producing lactones, which comprises reacting an amide compound of Formula (I): [wherein X represents a halogen atom; R, R' and R1 to R6 each independently represents a hydrogen atom or any desired substituent; and n represents an integer of 0 to 2] with an aqueous medium.
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- Process for preparing enantiomerically pure (S)-3-hydroxy-gamma-butyrolactone
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The present invention relates to a process for the in situ preparation of optically pure (S)-3,4-dihydroxybutyric acid derivatives represented by the Formula [2] and more particularly, to a process which enables preparing optically pure (S)-3-hydroxy-γ-butyrolactone represented by Formula [1] by oxidation of α- or β-(1,4) linked disaccharide or oligosaccharide with an oxidant under basic condition to give acid and cyclization sequentially under acidic condition to give (S)-3-hydroxy-γ-butyrolactone.
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Page column 6
(2008/06/13)
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- Process for preparing optically pure (S)-3-hydroxy-γ-butyrolactone
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The present invention relates to a process for preparing optically pure (S)-3-hydroxy-γ-butyrolactone expressed by the following Formula 1 and more particularly, to a process that enables preparing optically pure (S)-3-hydroxy-γ-butyrolactone economically in large quantities, by: (a) Preparing α-(1,4) linked oligosaccharide with adequate sugar distribution by reacting starch which is easily available from natural product with enzyme under a specific condition; and (b) Performing oxidation and cyclization sequentially under a specific condition.
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-
- PROCESS FOR PRODUCING HYDROXYLACTONE
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A process of the present invention produces a hydroxylactone by subjecting an unsaturated carboxylic acid having a double bond not conjugated to a carboxyl group or an ester thereof to (i) a reaction with hydrogen peroxide in the presence of a metallic compound containing a metallic element selected from W, Mo, V and Mn or (ii) a reaction with a peroxide containing the metallic element to thereby yield a corresponding hydroxylactone having a hydroxyl group combined with one of carbon atoms constituting the double bond and being cyclized at the other carbon atom position. The metallic compound may be one selected from oxides, oxoacids and salts thereof. The unsaturated carboxylic acid includes, for example, β,γ-unsaturated carboxylic acids, γ,δ-unsaturated carboxylic acids, and δ,ε-unsaturated carboxylic acids. The process can produce hydroxylactones in high yields at low cost.
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-
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- Enantioselective entry to the Homalium alkaloid hoprominol: Synthesis of an (R,R,R)-hoprominol derivative
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The diastereoselective synthesis of the N- and O-protected hoprominol derivative (R,R,R)-6 is described. The building up of the bicyclic O-silylated and di(N-tosylated) asymmetric scaffold 6 succeeded by convergent preparation of the two basic chiral azalactam units 7a and 7b and their subsequent iterative linking by a known method (Scheme 5). Both 4-alkyl-hexahydro-1,5-diazocin-2(1H)-ones 7a and 7b were prepared from the chiral β-amino acid portions 10a and 10b, respectively, by application of a set of reactions (e.g., N-alkylation of 10a,b and Sb(OEt)3-assisted cyclization of the resulting open-chain intermediates) already known. In comparison with the total syntheses of homaline (1) and homoprine (2), the newness of the described synthesis lies in the asymmetric approach to the difunctionalized fatty acid derivative 10b starting from (-)-(S)-malic acid (9) (Schemes 3 and 4). Key step in the preparation of 10b was the diastereoselective amination of the optically pure α,β-unsaturated δ-hydroxy homoallylic ester 14 via conjugate intramolecular aza-Michael cyclization of the acylic δ-(carbamoyloxy) intermediate 11.
- Ensch, Corinne,Hesse, Manfred
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p. 233 - 246
(2007/10/03)
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- Synthesis of (R)-2-methyl-4-deoxy and (R)-2-methyl-4,5-dideoxy analogues of 6-phosphogluconate as potential inhibitors of 6-phosphogluconate dehydrogenase.
-
The synthesis of (2R)-2-methyl-4,5-dideoxy and (2R)-2-methyl-4-deoxy analogues of 6-phosphogluconate is described. The synthetic strategy relies on the Evans aldol reaction for the installation of the chiral centres in the 2- and 3-positions. The selective phosphorylation at the primary alcohol function of (2R,3S)-3,6-dihydroxy-2-methylhexanoic acid benzyl ester (5) and (2R,3S,5S)-3,5,6-trihydroxy-2-methylhexanoic acid benzyl ester (20) was achieved with dibenzyl phosphochloridate and dibenzyl phosphoiodinate respectively, working at low temperature. (2R,3S)-3-Hydroxy-2-methyl-6-phosphonoxyhexanoic acid (9) was obtained in 25% overall yield from 4-benzyloxybutanol and (2R,3S,5S)-3,5-dihydroxy-2-methyl-6-phosphonoxyhexanoic acid (28) in 10% overall yield from L-malic acid.
- Dardonville, Christophe,Gilbert, Ian H
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p. 552 - 559
(2007/10/03)
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- Industrialization of the Microbial Resolution of Chiral C3 and C4 Synthetic Units: From a Small Beginning to a Major Operation, a Personal Account
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This account describes the research and development of the microbial resolution of chiral C3 and C4 synthetic units through to the production stage. These chiral C3 and C4 synthetic units are mainly used for the production of various pharmaceuticals, new materials such as liquid crystals, chiral polymers, and natural compounds as well as in basic chemical research. The research started in 1983 and the industrial plant was built in 1994. The development is still ongoing and is being broadened to include C4 chiral units, chiral propylene glycol, and so on. This project started as simple research on the activated sludge from an epichlorohydrin plant and evolved through many events and much research to an industrial production. We describe the various implications and the flow of events in the research and development through to the production of these chiral C3 and C4 synthetic units.
- Kasai, Naoya,Suzuki, Toshio
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p. 437 - 455
(2007/10/03)
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- Process for producing optically active gamma-butyrolactone
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This invention provides a novel process for producing optically active 3-hydroxy-γ-butyrolactone in a short step, which is superior economically and in efficiency and industrially suitable by using a starting material which is inexpensive and easily available and reagents easy to handle. This invention relates to a process for producing optically active 3-hydroxy-γ-butyrolactone represented by formula I: wherein the symbol * means an asymmetric carbon atom, which comprises hydrogenating an optically active 4-substituted oxy-3-hydroxybutyrate represented by formula II: wherein R1 represents a C1-4 lower alkyl group, R2 represents a protective group for a hydroxyl group deprotected by hydrogenation with a heterogeneous hydrogenation catalyst, and the symbol * has the same meaning as defined above, in the presence of a heterogeneous hydrogenation catalyst and an acidic substance followed by deprotection and simultaneous ring closure thereof.
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- PROCESS FOR PREPARING OPTICALLY PURE (ι(S))-3-HYDROXY-GAMA-BUTYROLACTONE
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The present invention relates to a continuous process for preparing optically pure (S)-3,4-dihydroxybutyric acid derivatives expressed by the following Formula 1 and more particularly, to the continuous process which enables preparing optically pure (S)-3,4-dihydroxybutyric acid derivatives economically in large quantities, by:(a) Preparing alpha-(1,4) linked oligosaccharide having adequate sugar distribution by reacting amylopectin which is easily available from natural product with enzyme under a specific condition; and(b) Performing oxidatioin by running basic anion exchange resin with an oxidant to give (S)-3,4-dihydroxybutyric acid-anion exchange resin complex, dissociating the (S)-3,4-dihydroxybutyric acid from anion exchange resin complex and esterification sequentially under a specific condition. wherein Represents linear or branched alkyl group with 1~5 carbon atoms.
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- Process for preparing 1,3-alkanediol from epoxide derivative
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A process for preparing an 1,3-alkanediol through carbonylation of an epoxide derivative includes the steps of (a) reacting an epoxide derivative with alcohol and carbon monoxide in a solvent at a temperature from about 30 to about 150° C. and at a pressure from about 50 to about 3000 psig in the presence of a catalyst system including an effective amount of a cobalt catalyst and an effective amount of a promoter to afford a reaction mixture including a 3-hydroxyester or derivative thereof in an amount of from 2 to about 95% by weight, (b) separating the reaction product and solvent from the catalyst and promoter, (c) reacting said reaction product and solvent with hydrogen at a temperature from about 30 to about 350° C. and at a pressure from about 50 to about 5000 psig in the presence of a catalyst system for hydrogenation to prepare a hydrogenation product mixture including a 1,3-alkanediol, and (d) recovering the 1,3-alkanediol from the hydrogenation product mixture. Catalyst systems for carrying out the inventive processes are also provided.
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Page column 9
(2008/06/13)
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- Ordered polyacetylenes and process for the preparation thereof
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Polyacetylene compounds and process for the preparation thereof from a chiral dihydroxy amide are described. The compounds preferably have diacyl groups attached to the amide. The compounds are useful for making films which are electrically conductive, near infrared absorbing, polarizing, and have the characteristic optical and other properties of polyacetylenes.
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- Process for the preparation of 3,4-dihydroxybutanoic acid and derivatives thereof from substituted pentose sugars
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A process for the preparation of 3,4-dihydroxybutanoic acid (I) and 3-hydroxy-γ-butyrolactone (V) thereof from a 3-leaving group substituted pentose source is described. In particular, the process relates to the synthesis of (R)-3,4-dihydroxybutanoic acid and (R)-3-hydroxy-γ-butyrolactone from a 3-leaving group substituted L-pentose sugars. The process uses a base and a peroxide to convert the pentose source to the chiral 3,4-dihydroxybutanoic acid compound. The chiral 3,4-dihydroxybutanoic acid can be further converted to 3-hydroxy-γ-butyrolactone by acidification. The chiral compound is useful as a chemical intermediate to the synthesis of various drugs and other products.
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- Process for preparing β-hydroxy-γ-butyrolactones and β-(meth)acryloyloxy-γ-butrolactones
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The present invention provides a process for preparing β-hydroxy-γ-butyrolactone or β-methyl-β-hydroxy-γ-butyrolactone represented by the formula (1): wherein R1is hydrogen or methyl, which entails a) cyanating glycidol or 2-methyl-2,3-epoxypropanol, b) hydrolyzing the product of step a), and c) lactonizing the product of step b).
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- Hepatoprotective aliphatic glycosides from three Goodyera species
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Hepatoprotective aliphatic glycosides 3-(S)-3-β-D- glucopyranosyloxybutanolide (1) and its congener, 3-(S)-3-β- glucopyranosyloxy-4-hydroxybutanoic acid (2) were isolated as major constituents from the whole plants of three Goodyera species, G. schlechtendaliana REICHB. fil., G. matsumurana SCHLTR. and G. discolor KER- GAWL. The structures of 1 and 2 have been determined by NMR, MS spectroscopic and chemical means. Compound 1 was converted into its methyl ester form (5) during the purification step, when the lactone ring was cleaved by catalysis of silica gel with the CHCl3-MeOH-H2O as a solvent. On the other hand, 1 was obtained in a high yield by the same purification procedure without MeOH. Based on this fact, a simple and economic method for the purification of 1 was confirmed. Compounds 1 and 2 were found to have a hepatoprotective effect on liver injury induced by carbon tetrachloride in primary cultured rat hepatocytes.
- Du, Xiao-Ming,Sun, Ning-Yi,Chen, Yang,Irino, Nobuto,Shoyama, Yukihiro
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p. 731 - 734
(2007/10/03)
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- Optical resolution method of (.+-.)-3,4-dihydroxybutanoic acid
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An optical resolution method of (.+-.)-3,4-dihydroxybutanoic acid, by reacting (.+-.)-3,4-dihydroxybutanoic acid with an optically active primary amine or secondary amine. Also a method for producing optically active 3-hydroxy-γ-butyrolactone, by reacting (.+-.)-3,4-dihydroxybutanoic acid with an optically active primary amine or secondary amine for optical resolution, and ring closing the resulting optically active 3,4-dihydroxybutanoic acid.
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- Process for preparing optically pure (S)-3-hydroxy- gamma -butyrolactone
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The present invention relates to a process for preparing optically pure (S)-3-hydroxy- gamma -butyrolactone expressed by the following Formula 1 and more particularly, to a process that enables preparing optically pure (S)-3-hydroxy- gamma -butyrolactone economically in large quantities, by: (a) Preparing alpha -(1,4) linked oligosaccharide with adequate sugar distribution by reacting amylopectin which is easily available from natural product with enzyme under a specific condition; and (b) Performing oxidation, esterification and cyclization sequentially under a specific condition.
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- Phenolic glucosides and a γ-lactone glucoside from the sprouts of Crocus sativus
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Two new phenolic glucosides, a new γ-lactone glucoside, and adenosine were isolated from the sprouts of Crocus sativus L. The new compounds were characterized as 2,4-dihydroxy-6-methoxyacetophenone-2β-D-glucopyranoside (1), 2,3,4-trihydroxy-6-methoxyacetopenone-3-β-D-glucopyranoside (2) and 3- (S)-3-β-D-glucopyranosyloxybutanolide (3), respectively. All structures were elucidated on the basis of chemical and spectroscopic evidence.
- Gao, Wen-Yun,Li, Yi-Ming,Zhu, Da-Yuan
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p. 425 - 427
(2007/10/03)
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- Process for preparing optically active cyclic compounds
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A process for preparing optically active 3-hydroxy-γ-butyrolactone or optically active 3-hydroxytetrahydrofuran through a short route and by using an easily available and inexpensive starting material and an inexpensive reagent easy to handle is disclosed. The process comprises cyclizing an optically active compound represented by formula (II): STR1 wherein Q represents an alkoxycarbonyl group having 1 to 4 carbon atoms or a hydroxymethyl group; X represents a halogen atom; and the asterisk * means an asymmetric carbon atom, under an acidic condition.
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- Process for the preparation of (S)-β-hydroxy-γ-butyrolactone
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A process for producing (S)-β-hydroxy-γ-butyrolactone, a versatile intermediate used in several organic syntheses, from (S)-carnitine which is an unexpensive waste-product obtained from the production of (R)-carnitine by the resolution of racemic mixtures, is disclosed.
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- Practical syntheses of (S)-4-hydroxytetrahydrofuran-2-one, (S)-3-hydroxytetrahydrofuran and their (R)-enantiomers
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Optically active 4-hydroxytetrahydrofuran-2-one (3) has been synthesized in good yield from optically active ethyl 4-chloro-3-hydroxybutanoate (2) by refluxing with dilute hydrochloric acid. In a similar manner, optically active 3-hydroxytetrahydrofuran (5) was prepared from optically active 4-chloro-1,3-butanediol (4), which was derived from 2 by NaBH4 reduction. These new cyclizations proceed without racemization. VCH Verlagsgesellschaft mbH, 1997.
- Yuasa, Yoshifumi,Tsuruta, Haruki
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p. 1877 - 1879
(2007/10/03)
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- Single Step Conversion of Chiral Carnitine and Derivatives into (S)- and (R)-β-Substituted-γ-Butyrolactones
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This paper describes an efficient single step transformation of chiral carnitine and carnitine derivatives into stereoisomerically pure (S)- and (R)-β-substituted-γ-butyrolactones, obtained by intramolecular nucleophilic displacement. (S)- Or (R)-carnitine and (R)-aminocarnitine inner salts give β-hydroxy-γ-butyrolactone and β-amino-γ-butyrolactone respectively (82% and 77%) with the same configuration as the starting material. (R)-Acetylaminocarnitine inner salt gives (R)-β-acetylamino-γ-butyrolactone (90%), while (R)-acetylcarnitine gives 2(5H)-furanone under the same reaction conditions (77%, via cyclization and subsequent elimination reaction). (R)-N-Benzyloxycarnitineamide gives a mixture of pyrrolidinone (11%) and furanoyl imidate (50%) derivatives. The direct transformation of waste (S)-carnitine into the valuable (S)-β-hydroxy-γ-butyrolactone or (after acetylation) into the precious 2(5H)-furanone is of particular interest.
- Calvisi, Giuseppina,Catini, Roberto,Chiariotti, Wilma,Giannessi, Fabio,Muck, Sandra,Tinti, Maria Ornella,De Angelis, Francesco
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- Process for the preparation of (s)-beta-hydroxy-gamma-butyrolactone
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A process for producing (S)-β-hydroxy-γ-butyrolactone, a versatile intermediate used in several organic sintheses, from (S)-carnitine which is an unexpensive waste-product obtained from the production of (R)-carnitine by the resolution of racemic mixtures, is disclosed.
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- An efficient synthesis of C20-C25 building blocks for calyculin A
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The C20-C25 building blocks 2 and 3a for calyculin A, a protein phosphatase inhibitor, have been efficiently prepared from L-malic acid utilizing the Grignard reaction of the Weinreb amides 8 and 14, followed by stereoselective reduction of the ketones 9 and 15, respectively, as the key steps. Copyright
- Hamada, Yasumasa,Yokokawa, Fumiaki,Kabeya, Mototsugu,Hatano, Keiichiro,Kurono, Yukihisa,Shioiri, Takayuki
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p. 8297 - 8306
(2007/10/03)
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- A novel generation of optically active ethyl 4-chloro-3-hydroxybutyrate as a C4 chiral building unit using microbial dechlorination
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A novel procedure for the generation of optically active ethyl 4-chloro-3-hydroxybutyrate using bacterial cells was developed. Ethyl (S)-4-chloro-3-hydroxybutyrate was prepared by Pseudomonas sp. OS-K-29, which stereoselectively assimilates 2,3-dichloro-1-propanol. The reaction was based on its kinetic dehalogenation for both enantiomers using the resting cells. The obtained 4-chloro-3-hydroxybutyrate and high enantiomeric excess of >98% with a yield of 33% at the microbial resolution step. Moreover, several C4 compounds having the 4-chloro-3-hydroxyl function were also resolved and gave good enantiomeric purities (>95% ee). Ethyl (R)-4-chloro-3-hydroxybutyrate was also obtained with high enantiomeric purity (>98% ee) using the cells of Pseudomonas sp. DS-K-NR818. Copyright (C) Elsevier Science Ltd.
- Suzuki, Toshio,Idogaki, Hideaki,Kasai, Naoya
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p. 3109 - 3112
(2007/10/03)
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