- Anomeric alkylations and acylations of unprotected mono- and disaccharides mediated by pyridoneimine in aqueous solutions
-
A site-specific deprotonation followed by alkylations and acylations of sugar hemiacetals to the corresponding alkyl glycosides and acylated sugars in aqueous solutions is disclosed herein. Pyridoneimine as a new base is developed to mediate the deprotonation of readily available sugar hemiacetals and further reactions with alkylation and acylation agents.
- Dey, Kalyan,Jayaraman, Narayanaswamy
-
supporting information
p. 2224 - 2227
(2022/02/17)
-
- Rhamnogalacturonan II: Chemical Synthesis of a Substructure Including α-2,3-Linked Kdo**
-
The synthesis of a fully deprotected Kdo-containing rhamnogalacturonan II pentasaccharide is described. The strategy relies on the preparation of a suitably protected homogalacturonan tetrasaccharide backbone, through a post-glycosylation oxidation approach, and its stereoselective glycosylation with a Kdo fluoride donor.
- Mancuso, Enzo,Romanò, Cecilia,Trattnig, Nino,Gritsch, Philipp,Kosma, Paul,Clausen, Mads H.
-
supporting information
p. 7099 - 7102
(2021/04/19)
-
- Exploring the Biochemical Foundations of a Successful GLUT1-Targeting Strategy to BNCT: Chemical Synthesis and in Vitro Evaluation of the Entire Positional Isomer Library of ortho-Carboranylmethyl-Bearing Glucoconjugates
-
Boron neutron capture therapy (BNCT) is a noninvasive binary therapeutic modality applicable to the treatment of cancers. While BNCT offers a tumor-targeting selectivity that is difficult to match by other means, the last obstacles preventing the full har
- Matovi?, Jelena,J?rvinen, Juulia,Sokka, Iris K.,Imlimthan, Surachet,Raitanen, Jan-Erik,Montaser, Ahmed,Maaheimo, Hannu,Huttunen, Kristiina M.,Per?niemi, Sirpa,Airaksinen, Anu J.,Sarparanta, Mirkka,Johansson, Mikael P.,Rautio, Jarkko,Ekholm, Filip S.
-
p. 285 - 304
(2020/12/21)
-
- INHIBITORS OF MALARIAL AND PLASMODIUM FALCIPARUM HEXOSE TRANSPORTER AND USES THEREOF
-
Provided are molecules capable of binding to binding pockets of Plasmodium falciparum hexose transporter (PfHT) or analogs thereof and complexes comprising the same. Also provided herein are inhibitors of PfHT, pharmaceutical compositions comprising the i
- -
-
Paragraph 00513
(2021/08/14)
-
- Tea leaf perfumery precursor glucoside and synthesizing method thereof
-
The invention relates to a tea leaf perfumery precursor glucoside and a synthesizing method thereof. The synthesizing method comprises the following steps of synthesizing ten glucosides including aromatic alcohol ( alkanol )-beta -D-glucosides and aromatic alcohol (alkanol )-beta -D-primrose indicans. The synthesizing method disclosed by the invention is a glucoside synthesizing method which is good in selectivity, high in production rate and low in cost.
- -
-
Paragraph 0044-0046; 0056-0057
(2020/07/02)
-
- Conformationally Controlled Reactivity of Carbasugars Uncovers the Choreography of Glycoside Hydrolase Catalysis
-
Glycoside hydrolases (GHs) catalyze hydrolyses of glycoconjugates in which the enzyme choreographs a series of conformational changes during the catalytic cycle. As a result, some GH families, including α-amylases (GH13), have their chemical steps conceal
- Adabala, Pal John Pal,Akintola, Oluwafemi,Bennet, Andrew J.,Bhosale, Sandeep,Shamsi Kazem Abadi, Saeideh
-
p. 3336 - 3348
(2020/03/23)
-
- An Unexpected FeCl 3/C-Catalyzed β-Stereoselective Glycosylation in the Presence of the C(2)-Benzyl Group
-
An efficient and completely β-stereoselective glycosylation that did not rely on neighboring group participation is described using 2-20 molpercent FeCl 3 /C as the catalyst and benzylated propargyl glycosides as the donors to reach yields up to 96percent under mild condition. With an octatomic-ring intermediate at the α-face of FeCl 3 /C with alkyne of propargyl glycosides, a panel of aglycones comprising aliphatic, alicyclic, unsaturated alcohols, halogenated alcohols, and phenols with different substitution were examined successfully for the exclusive β-stereoselective glycosylation reaction.
- Guo, Hong,Li, Juan,Si, Wenshuai,Tang, Jie,Tang, Tianjun,Wang, Zhongfu,Yang, Guofang,Zhang, Jianbo
-
p. 2984 - 3000
(2019/07/22)
-
- Preparation of salidroside with n-butyl β-D-glucoside as the glycone donor via a two-step enzymatic synthesis catalyzed by immobilized β-glucosidase from bitter almonds
-
β-Glucosidase from bitter almonds was immobilized on epoxy group-functionalized beads for catalyzing salidroside synthesis in a two-step process with n-butyl-β-D-glucoside (BG) as the glucosyl donor. The formation of salidroside ((0.59 ± 0.02) M) at a yield of 39.04%±1.25% was accomplished in 8 h by the transglucosylation of immobilized β-glucosidase at pH?8.0 and 50 °C when the ratio of BG to tyrosol was 1:2 (mol/mol). A study on the influence of different glycosyl acceptors demonstrated that the yield of the glucosylation reaction of phenylmethanol and cyclohexanol was higher than that of either phenol or cyclohexanol. This may account for the selectivity of the immobilized enzyme towards the alcoholic hydroxyl group of tyrosol in the salidroside synthesis reaction. A study on the synthesis of BG via the reverse hydrolysis of immobilized β-glucosidase showed that a yield of 78.04%±2.2% BG can be obtained with a product concentration of (0.23 ± 0.015) M.
- Wang, Feng,Huang, Dengfa,Ma, Yong,Zhang, Fuming,Linhardt, Robert J.
-
p. 246 - 260
(2019/02/03)
-
- Multi-gram scale synthesis of a bleomycin (BLM) carbohydrate moiety: exploring the antitumor beneficial effect of BLM disaccharide attached to 10-hydroxycamptothecine (10-HCPT)
-
The “tumor-seeking” role of bleomycin (BLM) disaccharide has been demonstrated to serve as a promising tool for cancer diagnosis and a potential ligand for targeted therapy. However, these practical applications are often hampered by the lack of BLM disaccharide. Herein, an efficient multi-gram synthesis of peracetylated BLM disaccharide 20 is achieved by a TMSOTF-mediated glycosidation coupling manner in 43.6% overall yield in terms of benzyl galactoside. The critical innovation of the synthetic strategy is that inexpensive benzyl galactoside was first adopted to prepare an l-gulose subunit 3 as a glycosyl acceptor, with a much shorter route in 73.0% yield, and a 3-O-carbamoyl-mannose donor 4 was achieved in 47.2% yield by lowering the amount of dibutyltin oxide, and merging aminolysis and selective deacetylation into a one-pot reaction. Next, the incorporation of BLM disaccharide into 10-hydroxycamptothecin (10-HCPT), a non-specific model compound, to form conjugate 1 could significantly improve the antitumor activity and display obvious selectivity toward cancerous and normal cells in comparison with 10-HCPT. Moreover, BLM disaccharide itself was non-cytotoxic, clearly indicating the importance and potential of BLM disaccharide in solving the targeted antitumor therapy of cytotoxic drugs.
- Li, MaoLin,Huang, Weiping,Jiang, Zhilin,Shi, Yonghui,Yuan, Sisi,Fu, Kaishuo,Chen, YongJun,Zhou, Li,Zhou, Wen
-
p. 6010 - 6020
(2019/04/17)
-
- Preparation methods of 2-hydroxygulose receptor derivative, bleomycin disaccharide and precursor of bleomycin disaccharide
-
The invention discloses a preparation method of a 2-hydroxygulose receptor derivative. The method comprises the following steps: carrying out a series of reactions of ylidene protection on benzyl-beta-galactoside, 3-position configuration inversion, deacetylation, and selective acetylation. Meanwhile, the invention also discloses a method for preparing bleomycin disaccharide and a precursor of bleomycin disaccharide by using the 2-hydroxygulose receptor derivative prepared by the method as a receptor. According to the invention, through the adoption of the preparation method of the 2-hydroxygulose receptor derivative, the problems that sources of natural L-gulose are rare, cost is too high, and industrialization is not facilitated and the like are solved; meanwhile, the problems that the bleomycin disaccharide and the precursor of the bleomycin disaccharide are low in yield, reaction operability and repeatability are poor, industrialization is not facilitated and the like are solved. The preparation methods have the advantages that raw materials are cheap and easily available, the yield is high, the operability is high, conditions can be easily controlled, industrial amplificationcan be realized, efficiency is high, cost is low, and the like.
- -
-
Paragraph 0050-0057; 0076-0080; 0090-0094
(2019/01/08)
-
- A Sustainable One-Pot, Two-Enzyme Synthesis of Naturally Occurring Arylalkyl Glucosides
-
A sustainable, convenient, scalable, one-pot, two-enzyme method for the glucosylation of arylalkyl alcohols was developed. The reaction scheme is based on a transrutinosylation catalyzed by a rutinosidase from A. niger using the cheap commercially available natural flavonoid rutin as glycosyl donor, followed by selective “trimming” of the rutinoside unit catalyzed by a rhamnosidase from A. terreus. The process was validated with the syntheses of several natural bioactive glucosides, which could be isolated in up to 75 % yield without silica-gel chromatography.
- Bassanini, Ivan,Krejzová, Jana,Panzeri, Walter,Monti, Daniela,K?en, Vladimir,Riva, Sergio
-
p. 2040 - 2045
(2017/05/16)
-
- Triterpenoid glycosides from Ladenbergia hexandra Klotzsch
-
From the bark of Ladenbergia hexandra Klotzsch, ten triterpenoid glycosides were isolated along with five known compounds, and their structures were determined based on extensive NMR and mass spectroscopic, GC and HPLC analyses. Some triterpenoid glycosides contained 6-deoxy-D-allose or D-allose as a sugar moiety. The absolute stereochemical assignment of the sugars was determined by comparison with synthetic samples, as well as by GC and HPLC analysis.
- Furukawa, Megumi,Kamo, Satoshi,Makino, Mitsuko,Kurita, Masahiro,Tabata, Keiichi,Matsuzaki, Keiichi,Suzuki, Takashi,Uchiyama, Taketo
-
p. 147 - 155
(2017/03/02)
-
- Chemical Approach to Positional Isomers of Glucose-Platinum Conjugates Reveals Specific Cancer Targeting through Glucose-Transporter-Mediated Uptake in Vitro and in Vivo
-
Glycoconjugation is a promising strategy for specific targeting of cancer. In this study, we investigated the effect of d-glucose substitution position on the biological activity of glucose-platinum conjugates (Glc-Pts). We synthesized and characterized all possible positional isomers (C1α, C1β, C2, C3, C4, and C6) of a Glc-Pt. The synthetic routes presented here could, in principle, be extended to prepare glucose conjugates with different active ingredients, other than platinum. The biological activities of the compounds were evaluated both in vitro and in vivo. We discovered that varying the position of substitution of d-glucose alters not only the cellular uptake and cytotoxicity profile but also the GLUT1 specificity of resulting glycoconjugates, where GLUT1 is glucose transporter 1. The C1α- and C2-substituted Glc-Pts (1α and 2) accumulate in cancer cells most efficiently compared to the others, whereas the C3-Glc-Pt (3) is taken up least efficiently. Compounds 1α and 2 are more potent compared to 3 in DU145 cells. The α- and β-anomers of the C1-Glc-Pt also differ significantly in their cellular uptake and activity profiles. No significant differences in uptake of the Glc-Pts were observed in non-cancerous RWPE2 cells. The GLUT1 specificity of the Glc-Pts was evaluated by determining the cellular uptake in the absence and in the presence of the GLUT1 inhibitor cytochalasin B, and by comparing their anticancer activity in DU145 cells and a GLUT1 knockdown cell line. The results reveal that C2-substituted Glc-Pt 2 has the highest GLUT1-specific internalization, which also reflects the best cancer-targeting ability. In a syngeneic breast cancer mouse model overexpressing GLUT1, compound 2 showed antitumor efficacy and selective uptake in tumors with no observable toxicity. This study thus reveals the synthesis of all positional isomers of d-glucose substitution for platinum warheads with detailed glycotargeting characterization in cancer.
- Patra, Malay,Awuah, Samuel G.,Lippard, Stephen J.
-
supporting information
p. 12541 - 12551
(2016/10/07)
-
- 1,2-cis Alkyl glycosides: Straightforward glycosylation from unprotected 1-thioglycosyl donors
-
A 1,2-cis-alkyl glycosidation protocol that makes use of unprotected phenyl 1-thioglycosyl donors is reported. Glycosylation of various functionalized alcohols was accomplished in moderate to high yield and selectivity to give the 1,2-cis-glycosides. In order to quickly develop optimum glycosylation conditions, an FIA (flow injection analysis)-ESI-TOF-MS method was developed that enabled rapid and quantitative evaluation of yield on small scale. This methodology, coupled with NMR spectroscopy, allowed for rapid evaluation of the overall reactions.
- Meng, Bo,Zhu, Zhenqian,Baker, David C.
-
p. 5182 - 5191
(2014/07/08)
-
- Direct glycosylation of bioactive small molecules with glycosyl iodide and strained olefin as acid scavenger
-
A new strategy for diversity-oriented direct glycosylation of bioactive small molecules was developed. This reaction features (-)-β-pinene as acid scavenger and work with glycosyl iodides under mild conditions. With the aid of RP-HPLC and chiral SFC separation techniques, the new direct glycosylation proved effective at gram scale on bioactive small molecules including AZD6244, podophyllotoxin, paclitaxel, and docetaxel. Interesting glycoside derivatives were efficiently created with good yields and 1,2-cis selectivity.
- Gu, Xiangying,Chen, Lin,Wang, Xin,Liu, Xiao,You, Qidong,Xi, Wenwei,Gao, Li,Chen, Guohua,Chen, Yue-Lei,Xiong, Bing,Shen, Jingkang
-
p. 1100 - 1110
(2014/03/21)
-
- AMPHETAMINE PRODRUGS
-
The present invention relates to amphetamine prodrugs which provide colonic release of amphetamine.
- -
-
Paragraph 144; 145; 146
(2014/01/17)
-
- TANNIN INHIBITORS OF HIV
-
The invention provides a method to prevent or treat HIV-infection with synthetic tannins, and pharmaceutical compositions comprising synthetic tannins.
- -
-
Paragraph 0027
(2013/10/07)
-
- Synthesis of benzyl β-d-galactopyranoside by transgalactosylation using a β-galactosidase produced by the over expression of the Kluyveromyces lactis LAC4 gene in Arxula adeninivorans
-
The LAC4 gene of Kluyveromyces lactis encoding for β-galactosidase was overexpressed in the yeast Arxula adeninivorans to produce the enzyme, which can be used for the synthesis of β-d-galactosides. These compounds play a major role as precursors for the
- Rauter, Marion,Schwarz, Maria,Becker, Karin,Baronian, Keith,Bode, Ruediger,Kunze, Gotthard,Vorbrodt, H.-Matthias
-
p. 319 - 327
(2013/11/19)
-
- Chondroitin-4-O-sulfatase from Bacteroides thetaiotaomicron: Exploration of the substrate specificity
-
Bacterial sulfatases can be good tools to increase the molecular diversity of glycosaminoglycan synthetic fragments. A chondroitin 4-O-sulfatase from the human commensal bacterium Bacteroides thetaiotaomicron has recently been identified and expressed. In order to use this enzyme for synthetic purposes, the minimal structure required for its activity has been determined. For that, four 4-O-sulfated monosaccharides and one 4-O-sulfated disaccharide have been synthesized and used as substrates with the sulfatase. The minimum structure was shown to be a disaccharide but in contrast to the natural substrate, which must have a 4,5-insaturation, the enzyme accepts as substrate, a disaccharide with a saturated glucuronic acid at the non-reducing end and even a glucopyranosyl moiety without the carboxylic acid functionality.
- Malleron, Annie,Benjdia, Alhosna,Berteau, Olivier,Le Narvor, Christine
-
scheme or table
p. 96 - 99
(2012/07/01)
-
- Using ionic liquid cosolvents to improve enzymatic synthesis of arylalkyl β-d-glucopyranosides
-
Enzymatic synthesis of various arylalkyl β-d-glucopyranosides catalyzed by prune (Prunus domestica) seed meal via reverse hydrolysis in the mixture of organic solvent, ionic liquid (IL) and phosphate buffer was described. Among four hydrophilic organic solvents tested, ethylene glycol diacetate (EGDA) was found to be the most suitable for enzymatic synthesis of salidroside, a bioactive compound of commercial interest, from d-glucose and tyrosol. The effects of the nature of ionic liquids and their contents on the enzymatic glucosylation were studied. The addition of a suitable amount of ILs including denaturing ones was favorable to shift the reaction equilibrium toward the synthesis, thus improving the yields. Among the examined ILs, the novel IL [BMIm]I proved to be the best. And this IL was applied as the solvent in biocatalysis for the first time. The yields were found to be enhanced between 0.2-fold and 0.5-fold after the addition of 10% (v/v) [BMIm]I. In 10% (v/v) [BMIm]I-containing system, the desired arylalkyl β-d-glucopyranosides were synthesized with 15-28% yields, among which salidroside was obtained with a yield of 22%. .
- Yang, Rong-Ling,Li, Ning,Zong, Min-Hua
-
experimental part
p. 24 - 28
(2012/05/19)
-
- Synthesis and biological profiling of tellimagrandin I and analogues reveals that the medium ring can significantly modulate biological activity
-
A novel synthesis of the ellagitannin natural product tellimagrandin I and a series of medium ring analogues is described. These compounds were all subsequently screened for redox activity, ability to precipitate protein and cellular phenotype in HeLa cel
- Zheng, Shaojun,Laraia, Luca,O'Connor, Cornelius J.,Sorrell, David,Tan, Yaw Sing,Xu, Zhaochao,Venkitaraman, Ashok R.,Wu, Wenjun,Spring, David R.
-
supporting information; experimental part
p. 2590 - 2593
(2012/04/23)
-
- Efficient glycosylation of unprotected sugars using sulfamic acid: A mild eco-friendly catalyst
-
Sulfamic acid, a mild and environmentally benign catalyst has been successfully used in the Fischer glycosylation of unprotected sugars for the preparation alkyl glycosides. A diverse range of aliphatic alcohols have been used to prepare a series of alkyl glycosides in good to excellent yield.
- Guchhait, Goutam,Misra, Anup Kumar
-
experimental part
p. 52 - 57
(2012/01/15)
-
- First and biomimetic total synthesis of a member of the C-glucosidic subclass of ellagitannins, 5-O-desgalloylepipunicacortein A
-
The first total synthesis of a member of the C-glucosidic subclass of ellagitannins, 5-O-desgalloylepipunicacortein A, was accomplished by relying on a biomimetic aldol-type formation of its characteristic C-aryl glucosidic bond through the exploitation of the inherent chemical reactivity of a glucopyranosic hemiacetal precursor.
- Deffieux, Denis,Natangelo, Anna,Malik, Gaelle,Pouysegu, Laurent,Charris, Jaime,Quideau, Stephane
-
supporting information; experimental part
p. 1628 - 1630
(2011/03/22)
-
- Synthesis, biological activity of salidroside and its analogues
-
Salidroside is a phenylpropanoid glycoside isolated from Rhodiola rosea L., a traditional Chinese medicinal plant, and has displayed a broad spectrum of pharmacological properties. In this paper, about 18 novel salidroside analogues were prepared through Koenigs-Knorr method, the effects of these compounds over PC12 was assessed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The novel compounds differ in the substituents attached to the benzene ring or in the glycosyl donor. According to the data, compounds (3,5-dimethoxyphenyl)methyl β-D-glucopyranoside and (3,5-dimethoxyphenyl) methyl β-D-galactopyranoside with methoxy group at 3 and 5-positions of the benzene ring were the most viability at concentration of 300 μmol/l and 60 μmol/l, respectively.
- Guo, Yibing,Zhao, Yahong,Zheng, Cheng,Meng, Ying,Yang, Yumin
-
experimental part
p. 1627 - 1629
(2011/02/24)
-
- Highly efficient chemoenzymatic synthesis of β1-4-linked galactosides with promiscuous bacterial β1-4-galactosyltransferases
-
Two bacterial β1-4-galactosyltransferases, NmLgtB and Hp1-4GalT, exhibit promiscuous and complementary acceptor substrate specificity. They have been used in an efficient one-pot multienzyme system to synthesize LacNAc, lactose, and their derivatives including those containing negatively charged 6-O-sulfated GlcNAc and C2-substituted GlcNAc or Glc, from monosaccharide derivatives and inexpensive Glc-1-P.
- Lau, Kam,Thon, Vireak,Yu, Hai,Ding, Li,Chen, Yi,Muthana, Musleh M.,Wong, Denton,Huang, Ronald,Chen, Xi
-
supporting information; experimental part
p. 6066 - 6068
(2010/10/20)
-
- Glycosylation using unprotected alkynyl donors
-
(Chemical Equation Presented) Gold(III) activation of unprotected propargyl glycosyl donors has been shown to be effective for the synthesis of saccharides. Terminal propargyl glycosides of glucose, galactose, and mannose required heating at reflux in ace
- Mamidyala, Sreeman K.,Finn
-
experimental part
p. 8417 - 8420
(2010/01/16)
-
- Probing the aglycon promiscuity of an engineered glycosyltransferase
-
(Figure Presented) A sweet library: Two variants (wild-type (WT) and a triple mutant) of glycosyltransferase (GT) OleD have been shown to catalyze glycosylation of over 70 substrates, formation of O-, S- and N-glycosidic bonds, and iterative glycosylation (see scheme). Identified substrates include nucleophiles not previously known to act in GT reactions and span numerous natural product and therapeutic drug classes.
- Gantt, Richard W.,Goff, Randal D.,Williams, Gavin J.,Thorson, Jon S.
-
supporting information; experimental part
p. 8889 - 8892
(2009/05/26)
-
- Acyl group migration and cleavage in selectively protected β-D-galactopyranosides as studied by NMR spectroscopy and kinetic calculations
-
The migration of acetyl, pivaloyl, and benzoyl protective groups and their relative stabilities at variable pH for a series of β-D-galactopyranoses were studied by NMR spectroscopy. The clockwise and counterclockwise migration rates for the different este
- Roslund, Mattias U.,Aitio, Olli,Waerna, Johan,Maaheimo, Hannu,Murzin, Dmitry Yu.,Leino, Reko
-
supporting information; experimental part
p. 8769 - 8772
(2009/02/03)
-
- Engineering of glucoside acceptors for the regioselective synthesis of β-(1→3)-disaccharides with glycosynthases
-
Glycosynthase mutants obtained from Thermotoga maritima were able to catalyze the regioselective synthesis of aryl β-d-Galp-(1→3)-β-d-Glcp and aryl β-d-Glcp-(1→3)-β-d-Glcp in high yields (up to 90 %) using aryl β-d-glucosides as acceptors. The need for an aglyconic aryl group was rationalized by molecular modeling calculations, which have emphasized a high stabilizing interaction of this group by stacking with W312 of the enzyme. Unfortunately, the deprotection of the aromatic group of the disaccharides was not possible without partial hydrolysis of the glycosidic bond. The replacement of aryl groups by benzyl ones could offer the opportunity to deprotect the anomeric position under very mild conditions. Assuming that benzyl acceptors could preserve the stabilizing stacking, benzyl β-d-glucoside firstly assayed as acceptor resulted in both poor yields and poor regioselectivity. Thus, we decided to undertake molecular modeling calculations in order to design which suitable substituted benzyl acceptors could be used. This study resulted in the choice of 2-biphenylmethyl β-d-glucopyranoside. This choice was validated experimentally, since the corresponding β-(1→3) disaccharide was obtained in good yields and with a high regioselectivity. At the same time, we have shown that phenyl 1-thio-β-d-glucopyranoside was also an excellent substrate leading to similar results as those obtained with the O-phenyl analogue. The NBS deprotection of the S-phenyl group afforded the corresponding disaccharide quantitatively.
- Marton, Zsuzanna,Tran, Vinh,Tellier, Charles,Dion, Michel,Drone, Jullien,Rabiller, Claude
-
experimental part
p. 2939 - 2946
(2009/04/06)
-
- Synthesis of the mixed acetal segment of S-glyceroplasmalopsychosine
-
In this report the concept of converting carbohydrate to non-carbohydrate asymmetric molecules has been successfully exploited. The mixed acetal segment of glyceroplasmalopsychosine, a novel glycolipid, has been synthesized in a stereospecific manner using two simple sugar units. The glycosidation reaction between these two monosaccharides ensured the correct acetal stereocenter of the target molecule. Either olefin metathesis or heterogeneous Wittig reactions were used for constructing the long aliphatic chain of glyceroplasmalopsychosine.
- Parhi, Ajit K.,Mootoo, David R.,Franck, Richard W.
-
scheme or table
p. 9821 - 9827
(2009/04/03)
-
- Chemoenzymatic synthesis of naturally occurring benzyl 6-O-glycosyl-β- D-glucopyranosides
-
Direct β-glucosidation between benzyl alcohol and D-glucose (5) using the immobilized β-glucosidase from almonds with the synthetic prepolymer ENTP-4000 gave a benzyl β-D-glucoside (1) in 53% yield. The coupling of the benzyl β-D-glucopyranoside congener
- Kawahara, Eiji,Fujii, Mikio,Kato, Keisuke,Ida, Yoshiteru,Akita, Hiroyuki
-
p. 1058 - 1061
(2007/10/03)
-
- Selectively protected galactose derivatives for the synthesis of branched oligosaccharides
-
Synthesis and characterization of several new anomerically pure galactose derivatives, based on simple and effective protective group manipulations of benzyl β-D-galactopyranoside, are reported. The monosaccharides described contain selectively protected/deprotected hydroxyl functionalities at their 1,2,3,4- and 6-positions rendering them useful as building blocks for construction of branched oligosaccharides.
- Lehtil?, Reko L.,Lehtil?, Juho O.,Roslund, Mattias U.,Leino, Reko
-
p. 3653 - 3661
(2007/10/03)
-
- Synthesis of selected naturally occurring glucosides of volatile compounds. Their chromatographic and spectroscopic properties
-
Naturally occurring glucosides of benzyl alcohol, (±)-menthol, (+)-borneol, thymol, carvacrol and eugenol were synthesized by the Koenigs-Knorr-Zemplen method (yields 19.5-52.2 %). Their β-D-glucopyranosidic structures were determined by one- and two-dimensional homo-and heteronuclear 1H and 13C NMR spectroscopy. The β-configuration was additionally confirmed by the hydrolysis with β-glucosidase. Tetraacetyl-β-D-glucopyranosides, as intermediates, were GC-MS analyzed. Diastereomeric β-glucoside tetraacetates of (±)-menthol were well separated on the HP-101 column. The mass spectra of glucopyranoside tetraacetates were mutually compared, as well as with the spectra of their aglycones.
- Mastelic, Josip,Jerkovic, Igor,Vinkovic, Marijana,Dzolic, Zoran,Vikic-Topic, Drazen
-
p. 491 - 500
(2007/10/03)
-
- Use of apple seed meal as a new source of β-glucosidase for enzymatic glucosylation of 4-substituted benzyl alcohols and tyrosol in monophasic aqueous-dioxane medium
-
A facile method for enzymatic glycosylation of 4-substituted benzyl alcohols and tyrosol with glucose in a monophasic aqueous-dioxane medium was reported, using a crude meal of apple seed as a new catalyst. The corresponding β-D-glucosides were synthesized in moderate yields (13.1-23.1%), among which the salidroside was obtained in 15.8% yield.
- Tong, Ai Min,Lu, Wen Ya,Xu, Jian He,Lin, Guo Qiang
-
p. 2095 - 2097
(2007/10/03)
-
- Regioselective acylation of carbohydrate derivatives using lipases leading to a facile two-step procedure for the separation of some α- and β-glucopyranosides and galactopyranosides
-
The resolution of α- and β-anomers of glucopyranosides and galactopyranosides was achieved via enzyme-catalysed regioselective acylation. This two-step procedure to prepare pure α- and β-anomers of glycopyranosides would be most useful for the cases where glycosidases are not available or expensive to purchase. From a synthetic viewpoint, the regioselective acylation of glycopyranosides provides access to mono- and di-esters with well-defined substitution patterns.
- Gon?alves, Pedro M.L.,Roberts, Stanley M.,Wan, Peter W.H.
-
p. 927 - 932
(2007/10/03)
-
- Elucidation of the mechanism of polysaccharide cleavage by chondroitin AC lyase from Flavobacterium heparinum
-
Chondroitin AC lyase from Flavobacterium heparinum degrades chondroitin sulfate glycosaminoglycans via an elimination mechanism resulting in disaccharides or oligosaccharides with Δ4,5-unsaturated uronic acid residues at their nonreducing end. Mechanistic details concerning the ordering of the bond-breaking and -forming steps of this enzymatic reaction are nonexistent, mainly due to the inhomogeneous nature of the polymeric substrates. The creation of a new class of synthetic substrates for this enzyme has allowed the measurement of defined and reproducible kcat and Km values and has expanded the range of mechanistic studies that can be performed. The primary deuterium kinetic isotope effect upon kcat/Km for the abstraction of the proton α to the carboxylic acid was measured to be 1.67 ± 0.07, showing that deprotonation occurs in a rate-limiting step. Using substrates with leaving groups of differing reactivity, a flat linear free energy relationship was produced, indicating that the C4-O4 bond is not broken in a rate-determining step. Taken together, these results strongly suggest a stepwise mechanism. Consistent with this was the measurement of a secondary deuterium kinetic isotope effect upon kcat/Km of 1.01 ± 0.03 on a 4-{2H}-substrate, indicating that no sp2 character is developed at C4 during the rate-limiting step, thereby ruling out a concerted syn-elimination.
- Rye, Carl S.,Withers, Stephen G.
-
p. 9756 - 9767
(2007/10/03)
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- A strategy for chemical synthesis of selectively methyl-esterified oligomers of galacturonic acid
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The synthesis of monomethyl-esterified trigalacturonans 1-3 is described as part of a general strategy towards pectic oligosaccharides. The necessary monomeric building blocks were all prepared on a large scale from galactose pentaacetate. The glycosylations were carried out between galactose glycosyl donors and acceptors using the n-pentenyl glycosylation technique. Yields of the desired α-anomers were in the 50 to 74% range. The trigalactans thus obtained were then subjected to oxidation at C-6. Depending on the protecting group at this position the oxidation either produced the carboxylic acid or the corresponding methyl ester. Hereby, oligomers of galacturonic acid can be prepared with methyl esters introduced in a regiocontrolled fashion.
- Clausen, Mads H.,Jorgensen, Malene R.,Thorsen, Jesper,Madsen, Robert
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p. 543 - 551
(2007/10/03)
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- Synthesis of oligomeric assemblies of a platelet-binding key disaccharide in heparin and their biological activities
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Heparin, highly sulfated glycosaminoglycan, binds to platelets. A key disaccharide unit in heparin was previously found to be responsible for the binding, and the frequency of the disaccharide unit was important for the binding potency. A newly developed method based on the reductive amination was effectively applied to prepare structurally defined oligomeric assemblies possessing multiple units of the key disaccharide. From their platelet-binding activities measured by the competitive binding assay, the enhancement of the activity was clearly observed with increasing number of the key disaccharide.
- Koshida, Shuhei,Suda, Yasuo,Sobel, Michael,Kusumoto, Shoichi
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p. 1289 - 1292
(2007/10/03)
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- Improved synthesis of 2,3:4,6-di-O-isopropylidene-D-glucopyranose and -D-galactopyranose
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2,3:4,6-Di-O-isopropylidene-D-glucopyranose and -D-galactopyranose acetals are conveniently prepared by hydrogenolysis of benzyl 2,3:4,6-di-O-isopropylidene-β-D-glucopyranose and -β-D-galactopyranose in almost quantitative yields in 3 h. This result is in contrast with the sluggish reaction observed (48 h) when the hydrogenolysis was carried out on either anomeric α,β mixtures or on the corresponding α anomers. Copyright (C) 1999 Elsevier Science Ltd.
- Gomez, Ana M.,Danelon, Gerardo O.,Valverde, Serafin,Lopez, J. Cristobal
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p. 138 - 142
(2007/10/03)
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- Regio- and stereoselective synthesis of β-D-gluco-, α-L-ido-, and α- L-altropyranosiduronic acids from Δa4-uronates
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The stereoselective synthesis of β-D-glucopyranosiduronic, α-L- idopyranosiduronic, and α-L-altropyranosiduronic acids has been performed from different Δ4-uronate monosaccharides. Bromination of the C-4,5 double bond provided the trans-diaxial bromohydrin derivatives, which were converted to the corresponding epoxides in high yields. Direct reduction of the epoxides using boranetetrahydrofuran complex led to the corresponding glucuronic acids in low to good yields. Glucuronic acids were also obtained in satisfactory yields through a two-steps procedure involving bromination of the epoxide with titanium(IV) bromide followed by reduction using tributyltin hydride. Lewis acid-catalyzed rearrangement of these epoxides led to the corresponding α-L C-4 ketopyranosides adopting the 1C4 chair conformation. Hydride reduction afforded the α-L-idopyranosiduronic or the α-L- altropyranosiduronic acids, the stereoselectivity of the reduction being controlled by the appropriate substitution pattern.
- Bazin, Helene G.,Wolff, Michael W.,Linhardt, Robert J.
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p. 144 - 152
(2007/10/03)
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- A convenient preparative method for the glucosides of fatty alcohols and sterols
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The glucosides of simple fatty alcohols like n-octanol, n-triacoctanol and bcazyl alcohol as well as of cholesterol have been synthesised in very good yields (70-85 %) by reacting acetobromoglucose with zinc salts of the substrates, prepared in situ, and then deacetylating the glucoside peracetate. It is possible to obtain either of the anomers (α or β) selectively, by choosing appropriate reaction conditions.
- Nagarejan,Jagan Mohan Rao,Gunidutt
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p. 132 - 134
(2007/10/03)
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- Dehydrative glycosylation by diethylaminosulfur trifluoride (DAST) - tin(II) trifluoromethanesulfonate-tetrabutylammonium perchlorate - triethylamine system
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Dehydrative glycosylation using 2,3,4,6-tetra-O-benzyl-D-glucopyranose was carried out by the use of a condensing reagent system composed of diethylaminosulfur trifluoride (DAST), tin(II) triflate, tetrabutylammonium perchlorate, and triethylamine. Using this system, two tetrasaccharides, O- a-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→3)-Oα-D-glucopyranosyl- (1→4)-D-glucopyranose and O-a-D-glucopyranosyl-(1→3)-O-α-D- glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-D-glucopyranose, were synthesized.
- Hirooka, Motoko,Koto, Shinkiti
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p. 2893 - 2902
(2007/10/03)
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- A novel method for constructing β-D-mannosidic, 2-acetamido-2-deoxy-β-D-mannosidic and 2-deoxy-D-arabino-hexopyranosidic units from the bis(triflate) derivative of β-D-galactoside
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An efficient construction of the β-D-mannosidic, 2-acetamido-2-deoxy-β-D-mannosidic, 2-deoxy-2-fluoro-β-D-mannosidic, and 2-deoxy-β-D-arabino-hexopyranosidic units from the same intermediate, 2-4-bis(O-trifluoromethylsulfonyl) derivative of β-D-galactoside, was achieved in good yields in a stepwise inversion at C-4 and C-2 by using cesium acetate, n-Bu4NN3, n-Bu4NF, and n-Bu4NBH4. A convenient and practical protection of β-D-mannoside to the straightforward synthesis of antennary oligosaccharides was also achieved by using cesium trifluoroacetate.
- Sato,Yoshitomo,Takai
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p. 885 - 890
(2007/10/03)
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- Sensitive and Selective Screening for 6′-O-Malonylated Glucoconjugates in Plants
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Using synthesized reference compounds a screening for benzyl, 2-phenylethyl, geranyl, citronellyl, and 2,5-dimethyl-4-hydroxy-3(2H)-furanone 6′-O-malonyl β-D-glucopyranosides in various plant tissues was performed by high-performance liquid chromatography - electrospray ionization - tandem mass spectrometry (HPLC-ESI-MS/MS). The results obtained with fruits (guava; raspberry; strawberry), leaves (green tea; vine), and mountain papaya (Carica pubescens) peel indicate that malonylation of glycoconjugates is a common pathway in plant secondary metabolism.
- Withopf, Barbara,Richling, Elke,Roscher, René,Schwab, Wilfried,Schreier, Peter
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p. 907 - 911
(2007/10/03)
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- A Novel Method for Constructions of β-D-Mannosidic, 2-Acetamido-2-deoxy-β-D-mannosidic, and 2-Deoxy-β-D-arabino-hexopyranosidic Units from the Bis(triflate) Derivative of β-D-Galactoside
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The useful constructions of β-D-mannosidic, 2-acetamido-2-deoxy-β-D-mannosidic, and 2-deoxy-β-D-arabino-hexopyranosidic units from the same intermediate, 2,4-bis(O-trifluoromethanesulfonyl) derivative of β-D-galactoside, were achieved in a stepwise invers
- Sato, Ken-ichi,Yoshitomo, Akira
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- Syntheses of trehazolin derivatives and evaluation as glycosidase inhibitors
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The trehazolin derivatives 9-12 were synthesized from the aminocyclitol (7), which is the degradation product of trehazolin (5). In particular, compounds 9-11 were pseudodisaccharides that underwent replacement of the corresponding nonreducing D-glucose m
- Kobayashi,Shiozaki,Ando
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p. 2570 - 2580
(2007/10/02)
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- Inhibitory effects of perillosides A and C, and related monoterpene glucosides on aldose reductase and their structure-activity relationships.
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Monoterpene glucosides, perillosides A and C, obtained from the leaves of Perilla frutescens, were found to be inhibitors of aldose reductase (EC 1.1.1.21) which is considered to be a key enzyme in diabetic complications such as cataract. The apparent typ
- Fujita,Ohira,Miyatake,Nakano,Nakayama
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p. 920 - 926
(2007/10/02)
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- Chavicol β-D-glucoside, a phenylpropanoid heteroside, benzyl-β-D-glucoside and glycosidically bound volatiles from subspecies of Cedronella canariensis
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The volatile substances obtained after enzymatic hydrolysis of purified polar extracts from the aerial parts of two subspecies of Cedronella canariensis were shown to be, among others, benzyl alcohol (29.4percent), chavicol (11.6percent), cis-3-hexenol (9.3percent), 2-phenylethanol (8.6percent), cis-pinocarveol (5.1percent), myrtenol (2.2percent), 1-phenylethanol (2.0percent, tentatively), 1-octen-3-ol (1.8percent), 1-hexanol (1.1percent) for ssp. canariensis and chavicol (85.1percent), benzyl alcohol (2.5percent), cis-3-hexenol (2.5percent), 1-octen-3-ol (2.3percent); 1-hexanol (0.8percent) for ssp. anisata.Sugars detected in the polar fraction after hydrolysis were glucose, rhamnose and fructose.The main glycosides obtained from the polar fraction before hydrolysis were chavicol glucoside (6 ppm, ssp. anisata) and benzyl alcohol glucoside (2 ppm, ssp. canariensis).
- Coen, Matthias,Engel, Ralf,Nahrstedt, Adolf
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p. 149 - 156
(2007/10/02)
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