131233-91-5Relevant articles and documents
13C CP MAS NMR and crystal structure of methyl glycopyranosides
Paradowska, Katarzyna,Gubica, Tomasz,Temeriusz, Andrzej,Cyranski, Michal K.,Wawer, Iwona
, p. 2299 - 2307 (2008)
The X-ray diffraction analysis, 13C CP MAS NMR spectra and powder X-ray diffraction patterns were obtained for selected methyl glycosides: α- and β-d-lyxopyranosides (1, 2), α- and β-l-arabinopyranosides (3, 4), α- and β-d-xylopyranosides (5, 6) and β-d-ribopyranoside (7) and the results were confirmed by GIAO DFT calculations of shielding constants. In X-ray diffraction analysis of 1 and 2, a characteristic shortening and lengthening of selected bonds was observed in molecules of 1 due to anomeric effect and, in crystal lattice of 1 and 2, hydrogen bonds of different patterns were present. Also, an additional intramolecular hydrogen bond with the participation of ring oxygen atom was observed in 1. The observed differences in chemical shifts between solid state and solution come from conformational effects and formation of various intermolecular hydrogen bonds. The changes in chemical shifts originating from intermolecular hydrogen bonds were smaller in magnitude than conformational effects. Furthermore, the powder X-ray diffraction (PXRD) performed for 4, 5 and 7 revealed that 7 existed as a mixture of two polymorphs, and one of them probably consisted of two non-equivalent molecules.
SPINOSIDES A AND B. TWO CYTOTOXIC CUCURBITACIN GLYCOSIDES FROM DESFONTAINIA SPINOSA
Reddy, Kalakota S.,Amonkar, Ashok J.,Mccloud, Thomas G.,Chang, Ching-Jer,Cassady, John M.
, p. 3781 - 3786 (1988)
Fractionation of the active ethanol extract of Desfontainia spinosa based on cytotoxicity has led to the discovery of three new derivatives of the parent compound, 11-deoxocucurbitacin I.The structures of 23,24-dihydro-11-deoxocucurbitacin I and the glycosides, spinosides A and B were elucidated on the basis of extensive analysis of their high field 1H NMR, 13C NMR, high resolution mass spectra (fast atom bombardment, field desorption, chemical ionization, electron impact) and chemical interconversions.Spinosides A and B were cytotoxic in the KB cell culture assay.
Synthesis of 13C-Labeled Patulin [4-Hydroxy-4H-furo[3,2-c]pyran-2(6H)-one] to Be Used as Internal Standard in a Stable Isotope Dilution Assay
Rychlik,Schieberle
, p. 5163 - 5169 (1998)
A synthetic route was established for the preparation of [13C2]-4-hydroxy-4H-furo[3,2-c]pyran-2(6H)-one (patulin) to be used in a stable isotope dilution assay. Mass spectral analyses were performed using electron impact ionization (EI), negative electrospray ionization (ESI), collision-induced dissociation (CID), and atmospheric pressure ionization. Fragmentation routes in the EI mode and in CID were concluded and compared with each other.
Cleavage of 2-Phenyl-1,3-dioxolanes and Benzyl Ethers by Catalytic Transfer Hydrogenation
Bieg, Tadeusz,Szeja, Wieslaw
, p. 317 - 318 (1986)
The selective deprotection of 2-phenyl-1,3-dioxolane derivatives and benzyl ethers of carbohydrates can be accomplished by catalytic transfer hydrogenation using hydrazine hydrate as hydrogen donor and 10percent palladium on carbon as catalyst.Under these conditions, 2-phenyl-1,3-dioxan and 2-alkyl substituted 1,3-dioxolane moieties remain unaffected.The proposed method is effective and the deprotected compounds are obtained in high yields.
New lignan glycosides with potent antiinflammatory effect, isolated from Justicia ciliata
Day, Shiow-Hwa,Chiu, Nien-Yung,Tsao, Lo-Ti,Wang, Jih-Pyang,Lin, Chun-Nan
, p. 1560 - 1562 (2000)
Two new lignan glycosides, 4-O-[α-L-arabinopyranosyl-(1'''→2'')-β-D-xylopyranosyl-(1'''→5'')-β-D-ap iofuranosyl] diphyllin (1), named ciliatoside A (1), and 4-O-{[β-D-apiofuranosyl-(1''''→3''')-α-L-arabinopyranosyl-(1''''→2'')] [β-D-xylopyranosyl-(1''''→5'')]-β-D-apiofuranosyl}diphyllin (2), named ciliatoside B (2), were isolated from the whole plant of Justicia ciliata. The structures of 1 and 2 were determined by spectral and chemical methods. Compounds 1 and 2 strongly inhibited the accumulation of NO2- in lipopolysaccharide-stimulated RAW 264.7 cells in a concentration-dependent manner with IC50 values of 27.1 ± 1.6 and 29.4 ± 1.4 μM, respectively.
Efficient isomerization of methyl arabinofuranosides into corresponding arabinopyranosides in presence of pyridine
Prabhakar, Sunchu,Lemiègre, Lo?c,Benvegnu, Thierry,Hotha, Srinivas,Ferrières, Vincent,Legentil, Laurent
, p. 63 - 66 (2016)
Fisher glycosylation, the oldest but efficient reaction towards alkyl glycosides, suffers nonetheless from lack of selectivity, especially when dealing with pentoses. In this case, a mixture of the four isomers, namely the furanosides and the pyranosides, is formed. According to previous studies, the rate and selectivity of the reaction depend greatly on the reaction time and the temperature. In this report, another factor was evaluated, the introduction of a weak nucleophilic base. Interestingly, addition of pyridine few hours after the reaction has started allowed rapid isomerization of the methyl pentofuranosides into its pyranoside counterparts. The reaction proceeds with great diastereoselectivity using arabinose, ribose, xylose and lyxose as starting pentoses. Corresponding methyl pyranosides were obtained as the sole isomers with yields ranging from 65% to 75%.
TWO IRIDOID GLYCOSIDES FROM REHMANNIA GLUTINOSA
Morota, Takashi,Sasaki, Hiroshi,Nishimura, Hiroaki,Sugama, Ko,Chin Masao,Mitsuhashi, Hiroshi
, p. 2149 - 2154 (1989)
Key Word Index - Rehmannia glutinosa var. hueichingensis; Scrophulariaceae; iridoid glycosides; iridoid arabinoside; iridoid rutinoside; jioglutosides.Abstract - Two new iridoid glycosides named jioglutosides A and B, together with 11 known iridoid glycosides, have been isolated from the fresh roots of Rehmannia glutinosa var. hueichingensis.On the basis of chemical and spectral analyses, the structures of jioglutosides A and B have been elucidated.
Dehydration of Xylose to Furfural in Alcohol Media in the Presence of Solid Acid Catalysts
Iglesias, Jose,Melero, Juan A.,Morales, Gabriel,Paniagua, Marta,Hernández, Blanca
, p. 2089 - 2099 (2016)
Different solid acid catalysts, which include several zeolites, zirconium oxide based catalysts, and materials that contain sulfonic acids, have been evaluated in the dehydration of xylose to furfural in alcohol media. Alcohol media were selected to reduce side reactions, many of which occur in aqueous media. Among the tested alcohols, 2-propanol provided better results and yielded a higher furfural production than ethanol and methanol. Catalyst screening evidenced that small-pore-size zeolites (H-ZSM5) or catalysts that show weak acidity (tungstated zirconia) were unable to promote the desired transformation. Kinetic studies performed for the different types of materials revealed that the nature of the acid sites influenced the catalytic performance of the different solid acids to the extent of conditioning the main reaction pathway for the transformation of xylose into furfural. Thus, whereas Lewis acids seem to promote furfural production by the direct dehydration of xylose, Br?nsted-type catalysts lead to alkyl xylosides as intermediates in the overall transformation. Although both types of catalysts provide high furfural yields in short reaction times, especially at high temperatures, commercially available β-zeolite with an adequate combination of Br?nsted and Lewis acids sites seems to contain the right physicochemical properties to maximize furfural production.
Synthesis and structural insights into the binding mode of the albomycin δ1 core and its analogues in complex with their target aminoacyl-tRNA synthetase
De Graef, Steff,Gadakh, Bharat,Nautiyal, Manesh,Pang, Luping,Strelkov, Sergei V.,Van Aerschot, Arthur,Vondenhoff, Gaston,Weeks, Stephen D.
, (2020)
Despite of proven efficacy and well tolerability, albomycin is not used clinically due to scarcity of material. Several attempts have been made to increase the production of albomycin by chemical or biochemical methods. In the current study, we have synthesized the active moiety of albomycin δ1 and investigated its binding mode to its molecular target seryl-trna synthetase (SerRS). In addition, isoleucyl and aspartyl congeners were prepared to investigate whether the albomycin scaffold can be extrapolated to target other aminoacyl-tRNA synthetases (aaRSs) from both class I and class II aaRSs, respectively. The synthesized analogues were evaluated for their ability to inhibit the corresponding aaRSs by an in vitro aminoacylation experiment using purified enzymes. It was observed that the diastereomer having the 5′S, 6′R-configuration (nucleoside numbering) as observed in the crystal structure, exhibits excellent inhibitory activity in contrast to poor activity of its companion 5′R,6′S-diasteromer obtained as byproduct during synthesis. Moreover, the albomycin core scaffold seems well tolerated for class II aaRSs inhibition compared with class I aaRSs. To understand this bias, we studied X-ray crystal structures of SerRS in complex with the albomycin δ1 core structure 14a, and AspRS in complex with compound 16a. Structural analysis clearly showed that diastereomer selectivity is attributed to the steric restraints of the active site of SerRS and AspRS.
Methyl glycosides via Fischer glycosylation: translation from batch microwave to continuous flow processing
Aronow, Jonas,Stanetty, Christian,Baxendale, Ian R.,Mihovilovic, Marko D.
, p. 11 - 19 (2018/11/27)
Abstract: A continuous flow procedure for the synthesis of methyl glycosides (Fischer glycosylation) of various monosaccharides using a heterogenous catalyst has been developed. In-depth analysis of the isomeric composition was undertaken and high consistency with corresponding results observed under microwave heating was obtained. Even in cases where addition of water was needed to achieve homogeneity—a prerequisite for the flow experiments—no detrimental effect on the conversion was found. The scalability was demonstrated on a model case (mannose) and as part of the target-oriented synthesis of d-glycero-d-manno heptose, both performed on multigram scale.
