- "Click" glycodendrimers containing 27, 81, and 243 modified xylopyranoside termini
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(Chemical Equation Presented) A series of large glycodendrimers containing 27, 81, and 243 terminal modified xylose branches from the first (G 1-27) to the third generation (G3-243) were synthesized from 2′-azidoethyl 2,3,4-tri-O-acetyl-β-D-xylopyranoside and alkynyl-terminated dendrimers by "click" chemistry that is confirmed to be an excellent method to obtain large glycodendrimers exemplified by the use of modified xylose. The dendrimers were first characterized by 1H NMR, 13C{1H} NMR, elemental analysis, and IR spectroscopy. The size progression in the series was also demonstrated using both DOSY NMR and size exclusion chromatography (SEC), the latter technique showing the good polydispersity of all the dendrimers. The size measured by dynamic light scattering (DLS) for the dendrimer G3-243 is close to that obtained by the DOSY NMR method.
- Camponovo, Jeremy,Hadad, Caroline,Ruiz, Jaime,Cloutet, Eric,Gatard, Sylvain,Muzart, Jacques,Bouquillon, Sandrine,Astruc, Didier
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- Tandem β-elimination-Morita-Baylis-Hillman reaction in α,β-unsaturated sugar aldehydes
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The first Morita-Baylis-Hillman reaction of a 1-formylbutadiene derivative is reported. In addition, a convenient synthesis of 2-acetoxy-4-formylbutadiene derivatives starting from easily available D-galactal and D-arabinal is also described. Georg Thieme Verlag Stuttgart.
- Areces, Pilar,Carrasco, Esther,Mancha, Alicia,Plumet, Joaquin
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- Chemical synthesis and in vitro antitumor activity of quinizarin glycoside analogs
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A series of new glycoside derivatives of quinizarin were synthesized and characterized by NMR and IR spectrometry, and in vitro antitumor activity of some of these derivatives was evaluated against the mouse leukaemia P388 and the human leukaemia HL-60 cell lines by the standard MTT assay. They were proven to possess moderate antitumor activity. Copyright Taylor & Francis Group, LLC.
- Sun, Xiaofei,Ji, Li,Ren, Sumei,Wan, Shengbiao,Jiang, Tao
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- Photocatalyzed reductive fluoroalkylation of 2-acetoxyglycals towards the stereoselective synthesis of α-1-fluoroalkyl-: C -glycosyl derivatives
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A benign, efficient, regio- and stereoselective protocol for the syntheses of α-1-fluoroalkyl-C-glycosyl compounds bearing CF3, C4F9, and C6F13 substituents on the anomeric carbon has been developed by a new methodology starting from 2-acetoxyglycals for the first time. Remarkably, the reactions proceeded in only one step, through the visible light-photocatalyzed reductive fluoroalkylation of 2-acetoxyglycals by means of an Ir photocatalyst and employed commercially available fluoroalkyl iodides n-CnF2n+1-I (n = 1, 4, 6) as a source of fluoroalkyl radicals.
- Mora Flores, Erwin W.,Postigo, Al,Uhrig, María Laura
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- Excited-State Palladium-Catalyzed Radical Migratory Mizoroki-Heck Reaction Enables C2-Alkenylation of Carbohydrates
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Excited-state palladium catalysis has emerged as a promising strategy for developing novel and valuable reactions. Herein, we report the first excited-state Pd-catalyzed 1,2-radical migratory Mizoroki-Heck reaction that enables C2-alkenylation of carbohydrates using readily available 1-bromosugars and alkenes. The reaction tolerates a wide variety of functional groups and complex molecular architectures, including derivatives of natural products and marketed drugs. Preliminary mechanistic studies and DFT calculations suggest the involvement of visible-light-induced photoexcitation of Pd species, 1,2-spin-centered-shift (SCS) process, and Heck-type cross-coupling reaction. The reaction expands the reactivity profile of excited-state Pd catalysis and provides a streamlined protocol for the preparation of a wide variety of C2-alkenylated carbohydrate mimetics to aid the discovery and development of new therapeutics, agrochemicals, and materials.
- Liu, Peng,Mukherjee, Upasana,Ngai, Ming-Yu,Wu, Yue,Yao, Wang,Zhao, Gaoyuan,Zhou, Lin
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supporting information
p. 3353 - 3359
(2022/03/08)
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- Excited-State Palladium-Catalyzed 1,2-Spin-Center Shift Enables Selective C-2 Reduction, Deuteration, and Iodination of Carbohydrates
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Excited-state catalysis, a process that involves one or more excited catalytic species, has emerged as a powerful tool in organic synthesis because it allows access to the excited-state reaction landscape for the discovery of novel chemical reactivity. Herein, we report the first excited-state palladium-catalyzed 1,2-spin-center shift reaction that enables site-selective functionalization of carbohydrates. The strategy features mild reaction conditions with high levels of regio- and stereoselectivity that tolerate a wide range of functional groups and complex molecular architectures. Mechanistic studies suggest a radical mechanism involving the formation of hybrid palladium species that undergoes a 1,2-spin-center shift followed by the reduction, deuteration, and iodination to afford functionalized 2-deoxy sugars. The new reactivity will provide a general approach for the rapid generation of natural and unnatural carbohydrates.
- Zhao, Gaoyuan,Yao, Wang,Mauro, Jaclyn N.,Ngai, Ming-Yu
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supporting information
p. 1728 - 1734
(2021/02/06)
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- Chemical synthesis of 5’-β-glycoconjugates of vitamin B6
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Various 5’-β-saccharides of pyridoxine, namely the mannoside, galactoside, arabinoside, maltoside, cellobioside and glucuronide, were synthesized chemically according to KOENIGS-KNORR conditions using α4,3-O-isopropylidene pyridoxine and the respective acetobromo glycosyl donors with AgOTf (3.0 eq.) and NIS (3.0 eq.) as promoters at 0 °C. Furthermore, 5’-β-[13C6]-labeled pyridoxine glucoside (PNG) was prepared starting from [13C6]-glucose and pyridoxine. Additionally, two strategies were examined for the synthesis of 5’-β-pyridoxal glucoside (PLG).
- Bachmann, Thomas,Schnurr, Christian,Zainer, Laura,Rychlik, Michael
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supporting information
(2020/02/15)
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- Folding control of a non-natural glycopeptide using saccharide-coded structural information for polypeptides
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We synthesized "glyco-arylopeptides", whose folding structure significantly changes depending on the kind of saccharide in their side chain. The saccharide moiety interacts with the main chain via hydrogen bonding, and the non-natural polypeptides form two well-defined architectures - (P)-31- and (M)-41-helices - depending on the length of the saccharide chains and even the configuration of a single stereo-genic center in the epimers.
- Fujii, Naoka,Haino, Takeharu,Ishido, Yuki,Kanbayashi, Naoya,Okamura, Taka-Aki,Onitsuka, Kiyotaka
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supporting information
p. 2767 - 2770
(2020/03/13)
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- Neuroprotective activity of different monosaccharide-modified gastrodin analogs
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Gastrodin is a very important and well-known bioactive glycoside compound in Chinese medicine. It is also known as a drug with neuroprotective function. Here, a practical diversified synthesis of a series of gastrodin analogs was reported, which involved four-step procedures consisting of bromination, oxidation, etherification, and reduction. Various gastrodin analogs were obtained in good yields. The compound 4c in this study has a good neuroprotective function: it can significantly downregulate tumor necrosis factor-α and inducible nitric oxide synthase protein levels. The results of this study can provide a research basis for the development of neuroprotective drugs.
- Xu, Kun-Lun,Yu, Lan
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p. 1263 - 1269
(2020/01/21)
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- On the Catalytic Activity of a GT1 Family Glycosyltransferase from Streptomyces venezuelae ISP5230
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GT1 family glycosyltansferase, Sv0189, from Streptomyces venezuelae ISP5230 (ATCC 10721) was characterized. The recombinantly produced protein Sv0189 possessed UDP-glycosyltransferase activity. Screening, using an assay employing unnatural nitrophenyl glycosides as activated donors, resulted in the discovery of a broad substrate scope with respect to both acceptor molecules and donor sugars. In addition to polyphenols, including anthraquinones, simple aromatics containing primary or secondary alcohols, a variety of complex natural products and synthetic drugs were glucosylated or xylosylated by Sv0189. Regioselectivity was established through the isolation and characterization of glucosylated products. Sv0189 and homologous proteins are widely distributed among Streptomyces species, and their apparent substrate promiscuity reveals potential for their development as biocatalysts for glycodiversification.
- Forget, Stephanie M.,Shepard, Sydney B.,Soleimani, Ebrahim,Jakeman, David L.
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p. 11482 - 11492
(2019/10/02)
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- Aglycone Ebselen and β- D -Xyloside Primed Glycosaminoglycans Co-contribute to Ebselen β- D -Xyloside-Induced Cytotoxicity
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Most β-d-xylosides with hydrophobic aglycones are nontoxic primers for glycosaminoglycan assembly in animal cells. However, when Ebselen was conjugated to d-xylose, d-glucose, d-galactose, and d-lactose (8A-D), only Ebselen β-d-xyloside (8A) showed significant cytotoxicity in human cancer cells. The following facts indicated that the aglycone Ebselen and β-d-xyloside primed glycosaminoglycans co-contributed to the observed cytotoxicity: 1. Ebselen induced S phase cell cycle arrest, whereas 8A induced G2/M cell cycle arrest; 2. 8A augmented early and late phase cancer cell apoptosis significantly compared to that of Ebselen and 8B-D; 3. Both 8A and phenyl-β-d-xyloside primed glycosaminoglycans with similar disaccharide compositions in CHO-pgsA745 cells; 4. Glycosaminoglycans could be detected inside of cells only when treated with 8A, indicating Ebselen contributed to the unique property of intracellular localization of the primed glycosaminoglycans. Thus, 8A represents a lead compound for the development of novel antitumor strategy by targeting glycosaminoglycans.
- Tang, Yang,Zhang, Siqi,Chang, Yajing,Fan, Dacheng,Agostini, Ariane De,Zhang, Lijuan,Jiang, Tao
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p. 2937 - 2948
(2018/04/23)
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- Synthesis of β-D-xylopyranoside thiophosphate derivatives
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A method of synthesis of β-D-xylopyranoside thiophosphate derivatives was developed. Biological testing revealed a high insecticidal activity in the synthesized compounds.
- Belakhov,Garabadzhiu,Boikova,Antonova
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p. 456 - 462
(2017/05/01)
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- Potent Inhibitor of Drug-Resistant HIV-1 Strains Identified from the Medicinal Plant Justicia gendarussa
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Justicia gendarussa, a medicinal plant collected in Vietnam, was identified as a potent anti-HIV-1 active lead from the evaluation of over 4500 plant extracts. Bioassay-guided separation of the extracts of the stems and roots of this plant led to the isolation of an anti-HIV arylnaphthalene lignan (ANL) glycoside, patentiflorin A (1). Evaluation of the compound against both the M-and T-Tropic HIV-1 isolates showed it to possess a significantly higher inhibition effect than the clinically used anti-HIV drug AZT. Patentiflorin A and two congeners were synthesized, de novo, as an efficient strategy for resupply as well as for further structural modification of the anti-HIV ANL glycosides in the search for drug leads. Subsequently, it was determined that the presence of a quinovopyranosyloxy group in the structure is likely essential to retain the high degree of anti-HIV activity of this type of compounds. Patentiflorin A was further investigated against the HIV-1 gene expression of the R/U5 and U5/gag transcripts, and the data showed that the compound acts as a potential inhibitor of HIV-1 reverse transcription. Importantly, the compound displayed potent inhibitory activity against drug-resistant HIV-1 isolates of both the nucleotide analogue (AZT) and non-nucleotide analogue (nevaripine). Thus, the ANL glycosides have the potential to be developed as novel anti-HIV drugs.
- Zhang, Hong-Jie,Rumschlag-Booms, Emily,Guan, Yi-Fu,Wang, Dong-Ying,Liu, Kang-Lun,Li, Wan-Fei,Nguyen, Van H.,Cuong, Nguyen M.,Soejarto, Djaja D.,Fong, Harry H. S.,Rong, Lijun
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p. 1798 - 1807
(2017/06/28)
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- The application of aryl substituted derivatives of xylose as environmentally friendly multipurpose pesticides
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A series of aryl substituted derivatives of xylose have been synthesized. Biological tests have revealed high fungicidal activity of the resulting compounds against various phythopathogenic fungi. Additional biological studies have demonstrated high plant growth regulatory activity of the compounds synthesized.
- Belakhov,Garabadzhiu
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p. 3002 - 3007
(2017/07/07)
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- Click chemistry inspired highly facile synthesis of triazolyl ethisterone glycoconjugates
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Numerous deoxy-azido sugars 3 were prepared by the reaction of tosyl/bromo sugars with NaN3 in dry DMF under heating condition. The 1,3-dipolar cycloaddition of deoxy-azido sugars 3 with ethisterone 4 to afford regioselective triazole-linked ethisterone glycoconjugates 5 was investigated in the presence of CuI and DIPEA in dichloromethane or CuSO4· 5H2O and sodium ascorbate in aqueous medium. All the developed compounds were characterized by spectroscopic analysis (IR, 1H & 13C NMR, and MS spectra). Structure of triazolyl ethisterone glycoconjugate 5a has been further confirmed by its Single Crystal X-ray analysis.
- Kumar, Dhananjay,Mishra, Kunj B.,Mishra, Bhuwan B.,Mondal, Saheli,Tiwari, Vinod K.
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- Divergent synthesis of 2-C-branched pyranosides and oxepines from 1,2-gem-dibromocyclopropyl carbohydrates
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The ring opening of 1,2-(gem-dibromo)cyclopropyl carbohydrates by two different modes leads to either 2-C-(bromomethylene)pyranosides (using base) or 2-bromooxepines (using silver salts), as shown previously by us for a D-glucal-derived cyclopropane. The base-promoted ring opening is extended to encompass additional alcohol, thiol and amine nucleophiles, and diastereoisomeric cyclopropane precursors. Cross-coupling of the 2-C-(bromomethylene)pyranosides leads to extended 2-C-branched pyranosides. Silver-promoted ring expansion of the cyclopropyl carbohydrates in the presence of various alcohols is described. Cross-coupling of the resulting benzyl 2-bromooxepines affords 2-C-substituted oxepines.
- Moore, Peter W.,Schuster, Julia K.,Hewitt, Russell J.,Stone, M. Rhia L.,Teesdale-Spittle, Paul H.,Harvey, Joanne E.
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supporting information
p. 7032 - 7043
(2015/02/19)
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- SULFONATED COUMARINS, SYNTHESIS THEREOF, FLUOROGENIC SUBSTRATES RESULTING FROM GRAFTING SAID COUMARINS ONTO SUGARS, METHOD FOR PREPARING SAID SUBSTRATES, AND USES THEREOF
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Substituted sulfonated coumarins are expressed in the general formula (I), where: R1 is H, OH, or a substituted or unsubstituted, straight or branched C1-C6 alkyl radical, or —COR4, or —COOR4, or —CONHR4, R2 is H or a halogen, in particular fluorine, or a substituted or unsubstituted, straight or branched C1-C6 alkyl radical, or —COR4, or —COOR4, or —CONHR4, R1 and R2 being capable of together forming a ring, such as a substituted or unsubstituted aryl or furane, R3 is H or a halogen, in particular fluorine, or a substituted or unsubstituted, straight or branched C1-C6 alkyl radical, or —COR4, or —COOR4, or —CONHR4, where R4 is H, or a substituted or unsubstituted, straight or branched C1-C6 alkyl radical, or a substituted or unsubstituted aryl, and M is Na or K.
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Paragraph 0084; 0085
(2013/07/25)
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- Synthesis, thermal properties, and cytotoxicity evaluation of hydrocarbon and fluorocarbon alkyl β-d-xylopyranoside surfactants
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Alkyl β-d-xylopyranosides are highly surface active, biodegradable surfactants that can be prepared from hemicelluloses and are of interest for use as pharmaceuticals, detergents, agrochemicals, and personal care products. To gain further insights into th
- Xu, Wenjin,Osei-Prempeh, Gifty,Lema, Carolina,Davis Oldham,Aguilera, Renato J.,Parkin, Sean,Rankin, Stephen E.,Knutson, Barbara L.,Lehmler, Hans-Joachim
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scheme or table
p. 12 - 23
(2012/03/11)
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- Palladium-catalyzed ullmann-type reductive homocoupling of iodoaryl glycosides
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A catalytic synthesis of novel biaryl-linked divalent glycosides was achieved using an electroreductive palladium-catalyzed iodoaryl-iodoaryl coupling reaction. This new method was optimized for the synthesis of divalent biaryl-linked mannopyranosides that was subsequently generalized toward several carbohydrate substrates with yields up to 96%.
- Bergeron-Brlek, Milan,Giguere, Denis,Shiao, Tze Chieh,Saucier, Catherine,Roy, Rene
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experimental part
p. 2971 - 2977
(2012/05/04)
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- Synthesis of 1,2,3-triazoles from xylosyl and 5-thioxylosyl azides: Evaluation of the xylose scaffold for the design of potential glycogen phosphorylase inhibitors
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Various acetylenic derivatives and acetylated β-d-xylopyranosyl azide or the 5-thio-β-d-xylopyranosyl analogue were coupled by Cu(I)-catalyzed azide alkyne 1,3-dipolar cycloaddition (CuAAC) to afford a series of 1-xylosyl-4-substituted 1,2,3-triazoles. Controlled oxidation of the endocyclic sulfur atom of the 5-thioxylose moiety led to the corresponding sulfoxides and sulfones. Deacetylation afforded 19 hydroxylated xylose and 5-thioxylose derivatives, found to be only sparingly water-soluble. Compared to glucose-based analogues, they appeared to be much weaker inhibitors of glycogen phosphorylase, as the absence of a hydroxymethyl group weakens their binding at the enzyme active site. However, such new xylose derivatives might be useful glycomimetics.
- Goyard, David,Baron, Marc,Skourti, Paraskevi V.,Chajistamatiou, Aikaterini S.,Docsa, Tibor,Gergely, Pál,Chrysina, Evangelia D.,Praly, Jean-Pierre,Vidal, Sébastien
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- PROCESS FOR THE SYNTHESIS OF CLEISTANTHIN
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The present invention relates to a process for preparing compound of formula (I) that is Cleistanthin A. The process comprises the steps of reacting compound of formula (II) with compound of formula (III) in the presence of a first solvent, quarternary ammonium salt and first alkali to form compound of formula (IV). The compound of formula (IV) is further treated with a second solvent and a second alkali to form compound of formula (I). The present invention also relates to the preparation of salt of compound of formula (IV) that is Cleistanthin A acetate.
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Page/Page column 7
(2012/02/06)
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- Efficient synthesis of karrikinolide via Cu(II)-catalyzed lactonization
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The efficient total synthesis of karrikinolide (KAR1), a potent plant growth regulator discovered in smoke from burning plant material, is described. 3-Hydroxy-4-pyranone, prepared from d-xylose, was subjected to a Cu(II)-catalyzed transesterification-Wittig lactonization to afford the dihydrofuropyran in good yield. Finally, radical bromination, followed by olefin formation, provided KAR1 in acceptable yield.
- Matsuo, Kazumasa,Shindo, Mitsuru
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experimental part
p. 971 - 975
(2011/03/19)
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- Preparation of aminoethyl glycosides for glycoconjugation
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The synthesis of a number of aminoethyl glycosides of cell-surface carbohydrates, which are important intermediates for glycoarray synthesis, is described. A set of protocols was developed which provide these intermediates, in a short number of steps, from commercially available starting materials.
- Sardzik, Robert,Noble, Gavin T.,Weissenborn, Martin J.,Martin, Andrew,Webb, Simon J.,Flitsch, Sabine L.
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supporting information; experimental part
p. 699 - 703
(2011/01/03)
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- Enantioselective total synthesis of (-)-Clavosolide A and B
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Enantioselective total synthesis of (-)-clavosolide A and B was reported in full including the synthesis of proposed structure of (-)-clavosoldie A (1), revised structure of (-)-clavosoldie A (5), and revised structure of (-)-clavosoldie B (6). The relative and absolute stereochemistries of the natural products were confirmed unambiguously by comparing the optical rotation values and 1H and 13C NMR spectra of them.
- Son, Jung Beom,Kim, Si Nae,Kim, Na Yeong,Hwang, Min-Ho,Lee, Wonsun,Lee, Duck Hyung
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scheme or table
p. 653 - 663
(2010/08/19)
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- Syntheses of 1-thio-D-xylose and D-ribose esters of diorganoarsinous acids and their anticancer activity
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Several thio-D-xylose and D-ribose esters of dialkylarsinous acids have been synthesized. The crystal structure of 1-S-dimethylarsino-β-D- xylopyranose, 7a, has been obtained. Growth inhibition studies of about 60 strains of human cancer cells have been obtained in vitro for compounds 6a, 7a, 13, and 14. The results reveal that these compounds display a strong inhibition to subpanels of leukemia cells in vitro and high selectivity in inhibiting the growth of cancer cells.
- Gao, Mingzhang,Chen, Yiwen,Tan, Songde,Reibenspies, Joseph H.,Zingaro, Ralph A.
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p. 199 - 206
(2008/09/18)
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- Simple and efficient synthesis of novel glycosyl thiourea derivatives as potential antitumor agents
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The practical synthesis of pseudonucleosides incorporating thiourea derivative by coupling of monosaccharides (d-galactose, d-glucose and d-xylose) per-O-acetylated glycosyl isothiocyanates and different heterocyclic hydrazide derivatives is reported. The method involves the preparation of per-O-acetylated glycosyl isothiocyanates from per-O-acetylated sugars (two-step synthesis), which couple with heterocyclic hydrazides from amines to give thiourea-linked pseudonucleosides. All newly synthesized pseudonucleosides were assayed against human lung cancer-cell lines (PG) and human liver cancer-cell lines (BEL-7402) in vitro. The 2-(4-methoxybenzamide)-benzoimidazole-1-yl-acetyl pseudonucleosides showed moderate inhibition against these two cancer-cell lines with EC50 from 22.8 to 76.4 μM and from 54.9 to 82.4 μM, respectively. And the other compounds did not demonstrate any significant cytotoxicity even at concentrations up to 200 μM.
- Shusheng, Zhang,Tianrong, Zhan,Kun, Cheng,Youfeng, Xia,Bo, Yang
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experimental part
p. 2778 - 2783
(2009/04/11)
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- SYNTHESIS OF NOVEL XYLOSIDES AND POTENTIAL USES THEREOF
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The present invention includes a xyloside for use in inducing synthesis of a glycosaminoglycan in a cell, the xyloside having a chemical structure of one of Formula (1), Formula (2), Formula (3), Formula (4), Formula (5), Formula (6), Formula (7), Formula (8), Formula (9), or Formula (10) as shown herein. Also, the present invention includes a method of making a xyloside for use in inducing synthesis of a glycosaminoglycan in a cell, wherein the method is performed with "Click" chemistry. Additionally, the present invention includes a method of administering a xyloside so as to induce synthesis of a glycosaminoglycan in a cell.
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- Enantioselective total synthesis of (-)-clavosolide B
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Enantioselective synthesis of 2, a revised structure for (-)-clavosolide B, was accomplished by a convergent approach, where syn-selective aldol, hydroxy-directed cyclopropanation, Mitsunobu inversion, Schmidt-type glycosylation, and macrolactonization re
- Son, Jung Beom,Hwang, Min-Ho,Lee, Wonsun,Lee, Duck-Hyung
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p. 3897 - 3900
(2008/02/11)
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- Vitamin B12 and BF3-etherate as catalysts in synthesis of some C4-C12-alkyl β-D-xylopyranosides
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Two methods are presented for synthesis of some C4-C 12-alkyl β-D-xylopyranosides. The first method is the vitamin B12-catalyzed reaction of glycosylation of acetobromoxylose with alkanols (ROH) (C4-C12). The reaction is carried out with 2 mol% of vitamin B12, with respect to xylosyl bromide, under argon at room temperature. Under these conditions peracetylated C4-C 12-alkyl β-D-xylopyranosides are obtained. Following chromatographic purification these products are deesterified with a mixture of methanol-triethylamine-water (2:1:1) to give corresponding alkyl β-D-xylopyranosides in 50-60% yield. In all cases 3,4-di-O-acetyl- D-xylal is obtained, as the product of reductive elimination of peracetylated xylosyl bromide (15-25%). The second method is synthesis of C4-C 12-alkyl β- D-xylopyranosides performed by glycosylation of corresponding alkanols with tetra-O-acetyl β- D-xylopyranose in the presence of BF3-etherate, as a Lewis acid catalyst. This glycosylation proceeds in only moderate yield (45-55%), but simplicity of this method and avoidance of expensive heavy metal catalysts make such procedure attractive.
- Petrovi?, Zorica D.,Andjelkovi?, Dejan,Spasojevi?, Aleksandra
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p. 272 - 275
(2007/10/03)
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- Studies on the synthesis and antiproliferative activities of 13-cis-retinoyl sugar derivatives
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New retinoyl sugar derivatives of 13-cis-retinoic acid were synthesized in three ways in this paper in order to enhance pharmacal effects, especially antiproliferative activities of 13-cis-retinoic acid. Their structures were confirmed by IR, 1H-NMR, 13C-NMR, and MS spectra and their antiproliferative activities were determined in vitro using human cancer lines. Results showed that some compounds possessed potential antitumor activities. Copyright Taylor & Francis Group, LLC.
- Xiang, Jian-Nan,Jiang, Li-Hui,Chen, Chao-Yue,Fu, Zhi-Ying,Duan, Jun-Fei,He, Xiao-Xiao,Wang, Ke-Min
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p. 595 - 614
(2007/10/03)
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- DMF promoted xylosylation of terpenols
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The glycosidation of 2,3,4-triacetyl-1-bromo-α-d-xylopyranose with various terpenols occurs at 50°C in DMF without the requirement of any additive. The decisive role of DMF as solvent on the coupling efficiency is highlighted.
- Satgé, Céline,Le Bras, Jean,Hénin, Fran?oise,Muzart, Jacques
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p. 8405 - 8409
(2007/10/03)
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- Tetraphenylbacteriochlorin derivatives and compositions containing the same
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Provided is a tetraphenylbacteriochlorin derivative represented by the formula (I): 1[wherein R1, R2, R3 and R4, independently from each other, are a residue of a monosaccharide represented by the formulae: 2(wherein, R is a hydrogen or a protecting group)], or its salt. The tetraphenylbacteriochlorin derivative or its salt has a large molar extinction coefficient at long wavelengths which are expected to have a high tissue-penetrating property, and exhibits high selectivity to tumor cells and hydrophilicity.
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- Total synthesis of the anticancer natural product OSW-1
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The highly potent anticancer natural saponin OSW-1 has been successfully synthesized from commercially available 5-androsten-3β-ol-17-one 79 in 10 operations with 28% overall yield. The key steps in the total synthesis included a highly regio- and stereoselective selenium dioxide-mediated allylic oxidation of 80 and a highly stereoselective 1,4-addition of α-alkoxy vinyl cuprates 68 to steroid 17(20)-en-16-one 12E to introduce the steroid side chain. This total synthesis demonstrated once again the versatile synthetic applications of α-halo vinyl ether chemistry developed in our laboratories.
- Yu, Wensheng,Jin, Zhendong
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p. 6576 - 6583
(2007/10/03)
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- Synthesis and evaluation of potential inhibitors of chondroitin AC lyase from Flavobacterium heparinum
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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. The syntheses and testing of two potential inhibitors of this lyase are described. Methyl O-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-(1→4)-α -L-threo-hex-4-enopyranoside, 1, has the trigonal geometry at C5 of the uronic acid moiety expected at the transition state, yet retains the "leaving group" sugar moiety. Surprisingly, compound 1 showed no inhibition of the enzyme. The novel 5-nitro sugar, phenyl (5S)-5-nitro-β- D-xylopyranoside, 2, is a monosaccharide nitro analogue of the natural substrate, with C5 being a carbon acid of pKa 8.8. The rate of reprotonation of the anion generated at this center is sufficiently low that the anion of 2 can be used directly in initial steady-state velocity measurements without significant interference from the conjugate carbon acid. The anion of compound 2 was found to be a competitive inhibitor with a Ki value of 5 mM, whereas the conjugate acid had a Ki value of 35 mM.
- Rye, Carl S.,Withers, Stephen G.
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p. 4505 - 4512
(2007/10/03)
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- Solid-phase synthesis of O-linked glycopeptide analogues of enkephalin
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The synthesis of 18 N-α-FMOC-amino acid glycosides for solid-phase glycopeptide assembly is reported. The glycosides were synthesized either from the corresponding O'Donnell Schiff bases or from N-α-FMOC-amino protected serine or threonine and the appropriate glycosyl bromide using Hanessian's modification of the Koenigs-Knorr reaction. Reaction rates of D-glycosyl bromides (e.g., acetobromoglucose) with the L- and D-forms of serine and threonine are distinctly different and can be rationalized in terms of the steric interactions within the two types of diastereomeric transition states for the D/L and D/D reactant pairs. The N-α-FMOC-protected glycosides [monosaccharides Xyl, Glc, Gal, Man, GlcNAc, and GalNAc; disaccharides Gal-β(1-4)-Glc (lactose), Glc-β(1-4)-Glc (cellobiose), and Gal-α(1-6)-Glc (melibiose)] were incorporated into 22 enkephalin glycopeptide analogues. These peptide opiates bearing the pharmacophore H-Tyr-c[DCys-Gly-Phe-DCys]- were designed to probe the significance of the glycoside moiety and the carbohydrate-peptide linkage region in blood-brain barrier (BBB) transport, opiate receptor binding, and analgesia.
- Mitchell,Pratt,Hruby,Polt
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p. 2327 - 2342
(2007/10/03)
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- Rapid preparation of variously protected glycals using titanium(III)
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Glycosyl chlorides and bromides can be rapidly converted to glycals in high yield by reaction with (Cp2Ti[III]Cl)2. This reagent tolerates a wide range of common carbohydrate protecting groups, including silyl ethers, acetals, and esters; the methodology provides a general route for the preparation of glycals substituted with both acid- and base-labile functionality. A reaction mechanism is proposed that is based on heteroatom abstraction to give an intermediate glycosyl radical. This radical reacts with a second equivalent of Ti(III) to yield a glycosyltitanium(IV) species. β-Heteroatom elimination from the glycosyltitanium(IV) complex gives the glycal.
- Spencer, Roxanne P.,Cavallaro, Cullen L.,Schwartz, Jeffrey
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p. 3987 - 3995
(2007/10/03)
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- Absence of reverse anomeric effect in glycosylimidazoles
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The so-called reverse anomeric effect is the preference of cationic substituents for the equatorial position on a pyranose ring, but it is not consistent with theories of molecular structure. To reinvestigate this, we have measured the N-protonation-induc
- Perrin, Charles L.,Fabian, Miles A.,Brunckova, Jarmila,Ohta, Brian K.
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p. 6911 - 6918
(2007/10/03)
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- Synthesis of C-disaccharides via glucal dimerisation
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Treatment of 3-O-acetyl glucal and related species with acetylperchlorate provides good yields of the corresponding C-disaccharides with a high degree of stereocontrol at the new C-C bond. Copyright (C) 1996 Elsevier Science Ltd.
- Byerley, Andrew L. J.,Kenwright, Alan M.,Steel, Patrick G.
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p. 9093 - 9096
(2007/10/03)
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- Synthesis and confromational analysis of the plant hormone (auxin) related 2-(indol-3-yl)ethyl and 2-phenylethyl β-D-xylopyranosides and their 2,3,4-tri-O-acetyl derivatives
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The synthesis, structure analysis by X-ray diffraction and NMR spectroscopy (including also 1H NOE measurements), as well as molecular mechanics and dynamics of D-xylopyranose conjugates of 2-(indol-3-yl)ethanol (1) and 2-phenylethanol (2) are described.The per-O-acetylated derivatives of 2-(indol-3-yl)ethyl β-D-xylopyranoside (4β) and 2-phenylethyl β-D-xylopyranoside (7β) were prepared by Koenigs-Knorr condensation of the aglycone alcohols with 2,3,4-tri-O-acetyl-α-D-xylopyranosyl bromide.Glycoside 4β was deprotected to yield 2-(indol-3-yl) ethyl β-D-xylopyranoside (6).The crystal structures of 4β and 7β were determined.The crystals of both compounds are monoclinic, space group P 21 with a=11.985(1), b=7.317(1), c=12.428(1) Angstroem, β=93.2(1) deg, Z=2 (4β); a=5.809(1), b=19.833(1), c=8.912(1) Angstroem, β=106.0(1) deg, Z=2 (7β).The β-D-xylopyranose rings are in the 4C1 chair conformation.The results of the theoretical conformational analysis are compared with the values obtained from the experimental measurements in solid state and solution. Keywords: Auxin; Xylopyranosides; X-ray diffraction; NMR spectroscopy; NOE; Molecular dynamics
- Tomic, Sanja,Eijck, Bouke P. van,Kojic-Prodic, Biserka,Kroon, Jan,Magnus, Volker,et al.
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- Derivatives of 13-deoxycarminomycin
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An anthracycline compound (13-deoxycarminomycin) selected from the group consisting of anthracycline compounds represented by the following formula STR1 R1 is a hydroxy group, R2 represents a hydrogen atom or a hydroxyl group, R3 is a hydrogen atom, R4 represents one of the following groups (a) to (d) STR2 and if R2 is hydroxyl, R4 is not (d).
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- Synthesis of 4-O and 6-O-β-D-xylopyranosyl-D-glucopyranoses and their protein conjugates
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Benzyl 2,3,6-tri-O-benzyl-β-D-glucopyranoside (7) and benzyl 2,3,4-tri-O-benzyl-β-D-glucopyranoside (8) have been synthesized from D-glucose in seven steps.D-Xylosylation (Koenigs-Knorr) of these compounds gives benzyl 4-O-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-2,3,4-tri-O-benzyl-β-D-glucopyranoside (9) and benzyl 6-O-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-2,3,4-tri-O-benzyl-β-D-glucopyranoside (10) respectively.Subsequent deacetylation and hydrogenolysis affords 4-O-β-D-xylopyranosyl-D-glucose (13) and 6-O-β-D-xylopyranosyl-D-glucose (14) respectively.Thesedisaccharides have been coupled to human serum albumin by reductive amination procedure.
- Sen, Asish K.,Banerji, Nilima
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p. 818 - 823
(2007/10/02)
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- SYNTHESE EINES XYLOSE-HALTIGEN GLYCOPEPTIDES, DAS DIE AMINOSAEURE-SEQUENZ 4 BIS 7 DES NH2-TERMINUS DER PROTEIN-CORE-STRUCTUR DES RINDERHAUT-PROTODERMATAN-SULFATS ENTHAELT
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The synthesis is described of α-β-D-xylopyranosyl-L-serylglycyl-L-isoleucyl-glycine (7), a glycopeptide containing the amino acid sequence of the protein core-structure of beef-skin protodermatan sulfate; coupling of N-protected O-XylpSer with protected GlyIleuGly followed by deprotection afforded 7.
- Garg, Hari G.,Hasenkamp, Thomas,Paulsen, Hans
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p. 225 - 232
(2007/10/02)
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