- Ectyoceramide, the first natural hexofuranosylceramide from the marine sponge Ectyoplasia ferox
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Ectyoceramide (1a), a unique monoglycosylceramide with a galactose in the furanose form, was isolated from Ectyoplasia ferox, and its structure was determined by NMR spectroscopy, multiple tandem mass spectrometry, and chemical degradation. Ectyoceramide is the first example of a monohexofuranosylceramide and, more generally, the first natural glycosphingolipid with its first sugar in the furanose form.
- Costantino, Valeria,Fattorusso, Ernesto,Imperatore, Concetta,Mangoni, Alfonso
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- Sulfated liposaccharides inspired by telomerase inhibitor axinelloside A
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Sulfated liposaccharides are known inhibitors of telomerase and here we describe the synthesis of a series of sulfated liposaccharides inspired by the natural product axinelloside A, reported to act as an inhibitor of human telomerase. We established a robust and scalable synthetic route to galactosyl liposaccharides capitalizing on a series of regioselective acylation reactions with 2-decenoic acid and imidazolium sulfate esters.
- Guang, Jie,Rumlow, Zachary A.,Wiles, Lauren M.,O'Neill, Sloane,Walczak, Maciej A.
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- Blurring the boundary between bio- and geohopanoids: Plakohopanoid, a C32 biohopanoid ester from Plakortis cf. lita
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Plakohopanoid (3a), a new type of hopanoid derivative composed of a C 32 hopanoid acid ester linked to a mannosyl-myo-inositol, was isolated from the sponge Plakortis cf. lita as its peracetyl derivative 3b. The structure of 3b was determined by a combination of spectroscopic analysis and micro-scale chemical degradation. Even though plakohopanoid was isolated from a sponge, its component parts are clearly of bacterial origin, and its bacterial biosynthesis is very likely. Until now, C32 hopanoic acids have been considered to be geohopanoids, i.e., diagenetic products that are formed through abiotic degradation of the biohopanoids present in bacteria. The presence of 3a in a marine living organism shows that there is a biosynthetic pathway to C32 hopanoic acids, and these substances should therefore no longer with certainty be considered to be geohopanoids. Copyright
- Costantino, Valeria,Sala, Gerardo Della,Mangoni, Alfonso,Perinu, Cristina,Teta, Roberta
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p. 5171 - 5176
(2012/10/29)
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- Methyl 1,2-orthoesters as useful glycosyl donors in glycosylation reactions: A comparison with n-pent-4-enyl 1,2-orthoesters
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Mannopyranose-derived methyl 1,2-orthoacetates (R = Me) and -benzoates (R = Ph) can function as glycosyl donors - upon BF3·Et 2O activation in CH2Cl2 - in glycosylation reactions with monosaccharide acceptors to afford disaccharides in good yields. In the process, glycosylation is preferred to acid-catalyzed rearrangement leading to methyl mannopyranosides. Methyl 1,2-orthoesters can be also used in regioselective glycosylation protocols with monosaccharide diols, in which they display good regioselectivity. Copyright
- Uriel, Clara,Ventura, Juan,Gomez, Ana M.,Lopez, J. Cristobal,Fraser-Reid, Bert
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experimental part
p. 3122 - 3131
(2012/07/13)
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- Unexpected stereocontrolled access to 1α,1′β-disaccharides from methyl 1,2-ortho esters
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Mannopyranose-derived methyl 1,2-orthoacetates (R = Me) and 1,2-orthobenzoates (R = Ph) undergo stereoselective formation of 1α,1′β-disaccharides, upon treatment with BF 3?Et2O in CH2Cl2, rather than the expected acid-catalyzed reaction leading to methyl glycosides by way of a rearrangement-glycosylation process of the liberated methanol.
- Uriel, Clara,Ventura, Juan,Gomez, Ana M.,Lopez, J. Cristobal,Fraser-Reid, Bert
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experimental part
p. 795 - 800
(2012/03/22)
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- Isolation of the β-galactosphingolipid coniferoside using a tumor cell proteome reverse affinity protocol
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New approaches are vital to the development of marine natural products (MNP) as therapeutic leads. One of the more time consuming aspects of MNP research arises in the connection between structure and function. Here, we describe an isolation protocol that adapts tumor cell proteomes as a vehicle for MNP isolation therein uniting structural and functional analysis. Application of this method to extracts of the sponge Agelas conifera led to the isolation of a unique poly-hydroxybutyrated β-galactosphingolipid, coniferoside.
- La Clair, James J.,Rodriguez, Abimael D.
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experimental part
p. 6645 - 6653
(2011/12/21)
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- Synthesis and structure elucidation of benzoylated deoxyfluoropyranosides
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Benzoylated deoxyfluoropyranosides have been synthesized, starting with protected, unprotected, or fluorinated precursors. Fluorination of eight derivatives was compared using DAST and Deoxo-Fluor as reagents. Deoxo-Fluor was found to be especially useful
- Esmurziev, Aslan M.,Simic, Nebojsa,Hoff, Bard Helge,Sundby, Eirik
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scheme or table
p. 348 - 367
(2011/09/30)
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- 1 Hand 13C NMR data of methyl tetra-O-benzoyl-D- pyranosides in acetone-d6
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Complete assignments of 1H- and 13C-NMR resonances of five methyl tetra-O-benzoyl-D-pyranosides based on 1H, 13C, 2D DQF-COSY, HMQC, HMBC and HSQC-TOCSY experiments have been performed. Copyright
- Esmurziev, Asian,Simic, Nebojsa,Sundby, Eirik,Hoff, Bard Helge
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experimental part
p. 449 - 452
(2010/04/30)
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- Regioselective C-6 hydrolysis of methyl O-benzoyl-pyranosides catalysed by candida rugosa lipase
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Hydrolysis of six methyl O-benzoyl-pyranosides has been investigated using Candida rugosa lipase in dioxane/buffer mixtures. The lipase catalysed the hydrolysis of all substrates in a regiospecific manner at C-6, The rate of reaction was dependent on pyra
- Esmurziev, Asian,Sundby, Eirik,Hoff, Bard Helge
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body text
p. 1592 - 1597
(2009/09/08)
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- Thiodisaccharides with galactofuranose or arabinofuranose as terminal units: Synthesis and inhibitory activity of an exo β-d-galactofuranosidase
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Thiodisaccharides having β-d-Galf or α-l-Araf units as non-reducing end have been synthesized by the SnCl4- or MoO2Cl2-promoted thioglycosylation of per-O-benzoyl-d-galactofuranose (1), its 1-O-acetyl analogue 4, or per-O-
- Repetto, Evangelina,Marino, Carla,Laura Uhrig,Varela, Oscar
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experimental part
p. 2703 - 2711
(2009/08/07)
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- Antiplasmodial metabolites isolated from the marine octocoral Muricea austera
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Bioassay-guided fractionation of the MeOH extract from the octocoral Muricea austera collected in the Pacific coast of Panama led to the isolation of eight compounds, including three tyramine derivatives (1-3), two steroidal pregnane glycosides (4, 5), and three sesquiterpenoids (6-8). Compounds 2-5 are new natural products, and their structures were determined on the basis of their spectroscopic data (HRMS, 1D and 2D NMR, and CD studies). The antiprotozoal activities of the natural compounds 1-8 as well as those of a series of synthetic glycosides (11-22) and tyramine derivatives (23-35) were evaluated in vitro against a drug-resistant Plasmodium falciparum and intracellular form of Trypanosoma cruzi.
- Gutierrez, Marcelino,Capson, Todd L.,Guzman, Hector M.,Gonzalez, Jose,Ortega-Barria, Eduardo,Quinoa, Emilio,Riguera, Ricardo
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p. 1379 - 1383
(2008/09/20)
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- Glycolipids from sponges. Part 16.1 discoside, a rare myo-Inositol-containing glycolipid from the caribbean sponge Discodermia dissoluta
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Discoside (1a), a glycolipid composed of 4,6-O-diacylated mannose attached to the 2-hydroxyl group of a myo-inositol unit, was isolated as a mixture of homologues from the marine sponge Discodermia dissoluta. The complete stereostructure of this new glycolipid was solved by interpretation of mass spectrometric and NMR data and CD analysis of degradation products.
- Barbieri, Lucia,Costantino, Valeria,Fattorusso, Ernesto,Mangoni, Alfonso
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p. 1527 - 1530
(2008/09/20)
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- Glycolipids from Sponges. 13. Clarhamnoside, the First Rhamnosylated α-Galactosylceramide from Agelas clathrodes. Improving Spectral Strategies for Glycoconjugate Structure Determination
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Reinvestigation of the glycosphingolipid composition of the marine sponge Agelas clathrodes revealed the presence of a new tetraglycosylated α-galactoglycosphingolipid (1a), containing an unusual L-rhamnose unit in the sugar head. The structure of the new compound was elucidated using extensive 2D NMR studies. Because of the strong overlapping of the signals of the sugar protons in the 1H spectrum, 13C-coupled and 13C-decoupled phase-sensitive HMQC spectra were used to study the multiplicity of the overlapping signals. In addition, the absolute configuration of sugars was determined using a simple and efficient, yet underutilized CD method.
- Costantino, Valeria,Fattorusso, Ernesto,Imperatore, Concetta,Mangoni, Alfonso
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p. 1174 - 1179
(2007/10/03)
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- Reductive cleavage of the positional isomers of benzoylated and methylated methyl α-D-mannopyranoside
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The four O-benzoy-tri-O-methyl positional isomers, the six di-O-benzoyl-di-O-methyl positional isomers, the four tri-O-benzoyl-O-methyl positional isomers, and the tetra-O-benzoyl derivative of methyl α-D-mannopyranoside were synthesized, characterized, a
- Rozanas, Christine R.,Gray, Gary R.
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p. 243 - 249
(2007/10/03)
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