The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Hiroyuki Akita - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of naturally occurring β-d-Glucopyranoside based on enzymatic β-glycosidation
Journal of Molecular Catalysis B-enzymatic, 2006Co-Authors: Hiroyuki Akita, Eiji Kawahara, Masashi Kishida, Keisuke KatoAbstract:Abstract For the purpose of synthesis of naturally occurring β- d -Glucopyranoside, direct β-glycosidation for seven kinds of the functionalized primary alcohol in the presence of d -glucose using native or immobilized β-glucosidase (EC 3.2.1.21) from almonds under equilibrium condition was carried out. The utilization of high concentration of the alcohol acceptor, 3-methyl-2-buten-1-ol ( 3 ) or 2-methyl-2-propen-1-ol ( 4 ) using the immobilized enzyme gave the corresponding β- d -Glucopyranoside ( 21 , natural product) or ( 22 ) in 65 or 51% yield, respectively. On the other hand, the utilization of 4-equivalents of the functionalized alcohols ( 5 – 9 ) using the immobilized enzyme in 90% tert -butanol/H 2 O solution afforded the naturally occurring β- d -Glucopyranosides ( 23 – 27 ), respectively, in moderate yield. Among them, five kinds of β- d -Glucopyranosides ( 21 , 22 , 24 , 25 , and 27 ) were converted into the cyanoglucosides (rhodiocyanoside A ( 28 ), osmaronin ( 29 )) and other naturally occurring β- d -Glucopyranosides ( 30 – 32 ), respectively.
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simple preparation of phenylpropenoid β d Glucopyranoside congeners by mizoroki heck type reaction using organoboron reagents
Tetrahedron, 2005Co-Authors: Masashi Kishida, Hiroyuki AkitaAbstract:Palladium(II)-catalyzed carbon–carbon bond formation between allyl 2,3,4,6-tetra-O-acetyl-β-d-Glucopyranoside (3) and arylboronic acid congeners gave the corresponding cinnamyl 2,3,4,6-tetra-O-acetyl- β-d-Glucopyranosides (4a–m) in good yield. Among them, coupling products 4a–m were converted to not only the naturally occurring phenylpropenoid β-d-Glucopyranoside analogues (1a–e) but also the unnaturally ones (1f–m).
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simple synthesis of β d glycopyranosides using β glycosidase from almonds
Chemical & Pharmaceutical Bulletin, 2004Co-Authors: Katsumi Kurashima, Mikio Fujii, Hiroyuki AkitaAbstract:Enzymatic glycosidation of twenty-one kinds of alcohols (n-hepanol, n-octanol, 2-phenylethanol, 3-phenylpropanol, 4-phenylbutanol, 5-phenylpentanol, 6-phenylhexanol, furfury alcohol, 2-pyridinemethanol, isobutanol, isopentanol, p-methoxycinnamylalcohol) including secondary alcohols (isopropanol, cyclohexanol, 1-phenylethanol) and 1,ω-alkanediols (1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol), salicyl alcohol and 4-nitrophenyl β-D-Glucopyranoside (5) using β-glucosidase from almonds stereoselectively gave the corresponding β-D-Glucopyranosides in moderate yield.
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simple synthesis of β d glycopyranosides using β glycosidase from almonds
Chemical & Pharmaceutical Bulletin, 2004Co-Authors: Katsumi Kurashima, Mikio Fujii, Hiroyuki AkitaAbstract:Enzymatic glycosidation of twenty-one kinds of alcohols (n-hepanol, n-octanol, 2-phenylethanol, 3-phenylpropanol, 4-phenylbutanol, 5-phenylpentanol, 6-phenylhexanol, furfury alcohol, 2-pyridinemethanol, isobutanol, isopentanol, p-methoxycinnamylalcohol) including secondary alcohols (isopropanol, cyclohexanol, 1-phenylethanol) and 1,ω-alkanediols (1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol), salicyl alcohol and 4-nitrophenyl β-D-Glucopyranoside (5) using β-glucosidase from almonds stereoselectively gave the corresponding β-D-Glucopyranosides in moderate yield.
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Enzymatic β-glycosidation of primary alcohols
Journal of Molecular Catalysis B-enzymatic, 2003Co-Authors: Katsumi Kurashima, Mikio Fujii, Yoshiteru Ida, Hiroyuki AkitaAbstract:For the purpose of finding the best reaction conditions of β-glucosidation of primary alcohols, screening experiments in respect of the enzymes, glycosyl donors and solvents were carried out. The effective enzyme and glycosyl donor for the synthesis of benzyl β-d-Glucopyranoside (4) appeared to be β-glucosidase (EC 3.2.1.21) from almonds and 4-nitrophenyl β-d-Glucopyranoside (7), respectively. Enzymatic glycosidation of 10 kinds of primary alcohols (methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, 2-methoxyethanol, 2-ethoxyethanol, benzyl alcohol, (S)-(−)-perillyl alcohol) gave stereoselectively the corresponding β-d-Glucopyranosides (14–21, 4 and 22) in moderate yield, respectively.
Yanhua Zhang - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and properties of sugar-based surfactants alkoxyethyl β-D-Glucopyranoside
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2019Co-Authors: Wangzhen Shen, Yanhua Zhang, Langqiu Chen, Yulin Fan, Guoyong ChenAbstract:Abstract Alkyl glycosides as modern industrial manufactured products are important. Furthermore, the better water solubility should make them a greater potential application value. In this study, an improvement of water solubility has been realized by adding the oxyethene fragment (−OCH2CH2 ) as a hydrophilic spacer to the conventional alkyl glucoside structure, and the excellent surface properties of the alkyl glucoside were still maintained. The amphipathic properties of the prepared alkoxyethyl β-D-Glucopyranoside can be adjusted by the alkyl chain length (n). Alkoxyethyl β-D-Glucopyranosides were found to be water soluble with n ≤ 10. For both of CMC and γCMC, there was a monotonous decreasing trend with increasing the alkyl chain length. Such amphipathic molecules adsorbed preferentially on the solution surface and then formed spontaneously micelles in the aqueous solution by the hydrophobic effect. Nonyloxylethyl β-D-Glucopyranoside exhibited the finest foaming property, as well as the strongest emulsifying capacities in the rapeseed oil/water system and the toluene/water system. In addition, alkoxylethyl β-D-Glucopyranoside (n = 9–14) had thermotropic liquid crystal property and thermal stability below 230 °C. Alkoxyethyl β-D-Glucopyranoside, as a class of sugar-based surfactants, will be expected to be developed in a variety of practical application.
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Thermotropic phase behavior and surface-active properties of alkoxyethyl α-d-Glucopyranoside
Journal of Molecular Liquids, 2018Co-Authors: Yanhua Zhang, Langqiu Chen, Yulin FanAbstract:Abstract To overcome the inherent weakness of the traditional alkyl α- d -Glucopyranoside in water solubility and surface activity, a series of sugar-based surfactants alkoxyethyl α- d -Glucopyranosides were successfully synthesized by introducing an oxyethene spacer ( OCH2CH2 ). Herein, their thermotropic liquid crystalline and surface-active properties were investigated using DSC, POM and other methods. The phase transition temperature increased with increasing the alkyl chain length, meanwhile all glycosides were found to form the smectic phase since there was the typical focal-comic fan texture during cooling. Moreover, alkoxyethyl α- d -Glucopyranosides had better water solubility and finer surface activity than that of the traditional alkyl α- d -Glucopyranosides without an oxyethene fragment. Furthermore, the HLB number, solubility, CCMC value, γCMC value and Γmax value of alkoxyethyl α- d -Glucopyranoside had a tendency to decrease with increasing the alkyl chain length, whereas the logP value, πCMC value, Αmin value and pC20 value showed the opposite trend with increasing the alkyl chain length. In addition, decyloxyethyl α- d -Glucopyranoside showed the strongest emulsifying activity in n-octane/water system and rapeseed oil/water system, and it also had the best foaming properties. Therefore, an effective introduction of an oxyethyl fragment as a hydrophilic spacer indeed made an excellent contribution to improve water solubility and surface activity.
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Synthesis and properties of alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside
Journal of Molecular Liquids, 2017Co-Authors: Wangzhen Shen, Langqiu Chen, Yanhua ZhangAbstract:Abstract A class of novel sugar-based surfactants named alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranosides were constructed by the introduction of oxyethene fragment (-OCH2CH2-) in the traditional alkyl glycoside structure. Such alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranosides with different length of alkyl chain were synthesized, and their single configurations were confirmed to be α-anomer by 1H NMR and HRMS analysis. Their water solubility, surface tension, emulsification, foaming and thermal stability were investigated, and the effect of alkyl chain length on their surface property was also compared. The water solubility of alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside was significantly superior to that of alkyl 2-acetamido-2-deoxy-α-D-Glucopyranoside without an oxyethene fragment. Their dissolution process was an endothermic process and was driven by entropy increment as well. Alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside was disclosed to reduce significantly the surface tension of water. For both of CMC and γCMC, there was a decreasing trend with increasing of alkyl chain length. As increasing of alkyl chain length, the maximum surface adsorption (Γmax) increased and the molecular cross-sectional area (Amin) decreased. They adsorbed preferentially on the solution surface and then formed spontaneously micelles in solution by the hydrophobic effect. Nonyloxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside had the best foaming and emulsifying properties. All glycosides are thermally stable below 270 °C. In view of the improvement of the water solubility and maintainance of surface activity with the introduction of the hydrophilic spacer, the novel alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside should be expected to develop further its multiple applications as a class of novel water-soluble sugar-based surfactants in the future.
Oyvind M Andersen - One of the best experts on this subject based on the ideXlab platform.
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Anthocyanins from tubers and shoots of the purple potato, Solanum tuberosum
Journal of Horticultural Science & Biotechnology, 2000Co-Authors: Torgils Fossen, Oyvind M AndersenAbstract:SummaryThe anthocyanin content of tubers and shoots of the purple potato, Solanum tuberosum cv. Congo has been determined using various chromatographic and spectroscopic techniques to be petanin and the novel 3-O-[6-(4-ferulyl-O-α-rhamnopyranosyl)-β-Glucopyranoside]-5-O-β-Glucopyranosides of petunidin and malvidin. Acylated pigments constitute more than 98% of the total anthocyanin content both in tubers and shoots.
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Anthocyanin trisaccharides in blue berries of Vaccinium padifolium
Food Chemistry, 2000Co-Authors: Luis Cabrita, Nils Åge Frøystein, Oyvind M AndersenAbstract:Delphinidin 3-O-a-rhamnoside, malvidin 3-O-(6 00 -O-a-rhamnopyranosyl-b-Glucopyranoside) and the 3-O-(6 00 -O-a-rhamnopyranosyl-2 00 -O-b-xylopyranosyl-b-Glucopyranosides) of cyanidin, petunidin and peonidin were isolated by various chromatographic techniques from the edible berries of Vaccinium padifolium. Their complete structures were elucidated mainly by one- and twodimensional nuclear magnetic resonance spectroscopy. Together they account for 7% of the anthocyanin content in this species. No anthocyanidin 3-triglycoside, 3-rutinoside or 3-rhamnoside had previously been found in the genus Vaccinium. The 3-O-(6 00 -O-arhamnopyranosyl-2 00 -O-b-xylopyranosyl-b-Glucopyranosides) of petunidin and peonidin are novel compounds. # 2000 Elsevier
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Ampelopsin 7-glucoside and other dihydroflavonol 7-glucosides from needles of Picea abies
Phytochemistry, 1994Co-Authors: Rune Slimestad, Oyvind M Andersen, George W. FrancisAbstract:Abstract The 7- O -β-Glucopyranoside of ampelopsin (5,7,3′,4′,5′-pentahydroxydihydroflavonol), a novel dihydroflavonol, together with the 7- O -β-Glucopyranosides of taxifolin (5,7,3′,4′-tetrahydroxydihydroflavonol) and aromadendrin 5,7,4′-trihydroxydihydroflavonol have been isolated from needles of Norway spruce ( Picea abies ). The structures were established on the basis of acid hydrolysis, TLC and spectral data (UV, 1 H and 13 C NMR).
Takeo Kawabata - One of the best experts on this subject based on the ideXlab platform.
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Perfectly Regioselective and Sequential Protection of Glucopyranosides
European Journal of Organic Chemistry, 2010Co-Authors: Wataru Muramatsu, Kenji Mishiro, Yoshihiro Ueda, Takumi Furuta, Takeo KawabataAbstract:A perfectly regioselective and sequential method for the preparation of orthogonally protected Glucopyranosides has been developed. An acyl group was introduced at C(4)-OH by organocatalysis with >99 % regioselectivity. TBDPS, Boc, and BOM groups were sequentially introduced into the 4-O-acyl-Glucopyranoside at C(6)-OH, C(2)-OH, and C(3)-OH, respectively, with ca. 100 % regioselectivity in each step.
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Regioselective acylation of 6-O-protected octyl β-d-Glucopyranosides by DMAP catalysis
Tetrahedron Letters, 2007Co-Authors: Wataru Muramatsu, Takeo KawabataAbstract:Abstract Regioselectivity of acylation of 6-O-protected octyl β- d -Glucopyranosides was investigated. Treatment of octyl 6-O-methyl-β- d -Glucopyranoside with isobutyric anhydride in the presence of DMAP in toluene at −40 °C gave 3-O-isobutyryl derivative in >99% regioselectivity. Similar treatment of octyl 6-O-TBS-β- d -Glucopyranoside at −20 °C also gave 3-O-isobutyryl derivative in >99% regioselectivity.
Langqiu Chen - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and properties of sugar-based surfactants alkoxyethyl β-D-Glucopyranoside
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2019Co-Authors: Wangzhen Shen, Yanhua Zhang, Langqiu Chen, Yulin Fan, Guoyong ChenAbstract:Abstract Alkyl glycosides as modern industrial manufactured products are important. Furthermore, the better water solubility should make them a greater potential application value. In this study, an improvement of water solubility has been realized by adding the oxyethene fragment (−OCH2CH2 ) as a hydrophilic spacer to the conventional alkyl glucoside structure, and the excellent surface properties of the alkyl glucoside were still maintained. The amphipathic properties of the prepared alkoxyethyl β-D-Glucopyranoside can be adjusted by the alkyl chain length (n). Alkoxyethyl β-D-Glucopyranosides were found to be water soluble with n ≤ 10. For both of CMC and γCMC, there was a monotonous decreasing trend with increasing the alkyl chain length. Such amphipathic molecules adsorbed preferentially on the solution surface and then formed spontaneously micelles in the aqueous solution by the hydrophobic effect. Nonyloxylethyl β-D-Glucopyranoside exhibited the finest foaming property, as well as the strongest emulsifying capacities in the rapeseed oil/water system and the toluene/water system. In addition, alkoxylethyl β-D-Glucopyranoside (n = 9–14) had thermotropic liquid crystal property and thermal stability below 230 °C. Alkoxyethyl β-D-Glucopyranoside, as a class of sugar-based surfactants, will be expected to be developed in a variety of practical application.
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Thermotropic phase behavior and surface-active properties of alkoxyethyl α-d-Glucopyranoside
Journal of Molecular Liquids, 2018Co-Authors: Yanhua Zhang, Langqiu Chen, Yulin FanAbstract:Abstract To overcome the inherent weakness of the traditional alkyl α- d -Glucopyranoside in water solubility and surface activity, a series of sugar-based surfactants alkoxyethyl α- d -Glucopyranosides were successfully synthesized by introducing an oxyethene spacer ( OCH2CH2 ). Herein, their thermotropic liquid crystalline and surface-active properties were investigated using DSC, POM and other methods. The phase transition temperature increased with increasing the alkyl chain length, meanwhile all glycosides were found to form the smectic phase since there was the typical focal-comic fan texture during cooling. Moreover, alkoxyethyl α- d -Glucopyranosides had better water solubility and finer surface activity than that of the traditional alkyl α- d -Glucopyranosides without an oxyethene fragment. Furthermore, the HLB number, solubility, CCMC value, γCMC value and Γmax value of alkoxyethyl α- d -Glucopyranoside had a tendency to decrease with increasing the alkyl chain length, whereas the logP value, πCMC value, Αmin value and pC20 value showed the opposite trend with increasing the alkyl chain length. In addition, decyloxyethyl α- d -Glucopyranoside showed the strongest emulsifying activity in n-octane/water system and rapeseed oil/water system, and it also had the best foaming properties. Therefore, an effective introduction of an oxyethyl fragment as a hydrophilic spacer indeed made an excellent contribution to improve water solubility and surface activity.
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Synthesis and properties of alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside
Journal of Molecular Liquids, 2017Co-Authors: Wangzhen Shen, Langqiu Chen, Yanhua ZhangAbstract:Abstract A class of novel sugar-based surfactants named alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranosides were constructed by the introduction of oxyethene fragment (-OCH2CH2-) in the traditional alkyl glycoside structure. Such alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranosides with different length of alkyl chain were synthesized, and their single configurations were confirmed to be α-anomer by 1H NMR and HRMS analysis. Their water solubility, surface tension, emulsification, foaming and thermal stability were investigated, and the effect of alkyl chain length on their surface property was also compared. The water solubility of alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside was significantly superior to that of alkyl 2-acetamido-2-deoxy-α-D-Glucopyranoside without an oxyethene fragment. Their dissolution process was an endothermic process and was driven by entropy increment as well. Alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside was disclosed to reduce significantly the surface tension of water. For both of CMC and γCMC, there was a decreasing trend with increasing of alkyl chain length. As increasing of alkyl chain length, the maximum surface adsorption (Γmax) increased and the molecular cross-sectional area (Amin) decreased. They adsorbed preferentially on the solution surface and then formed spontaneously micelles in solution by the hydrophobic effect. Nonyloxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside had the best foaming and emulsifying properties. All glycosides are thermally stable below 270 °C. In view of the improvement of the water solubility and maintainance of surface activity with the introduction of the hydrophilic spacer, the novel alkoxyethyl 2-acetamido-2-deoxy-α-D-Glucopyranoside should be expected to develop further its multiple applications as a class of novel water-soluble sugar-based surfactants in the future.