97974-20-4Relevant academic research and scientific papers
Interplay of Protecting Groups and Side Chain Conformation in Glycopyranosides. Modulation of the Influence of Remote Substituents on Glycosylation?
Dharuman, Suresh,Amarasekara, Harsha,Crich, David
, p. 10334 - 10351 (2018/09/06)
The synthesis and conformational analysis of a series of phenyl 2,3,6-tri-O-benzyl-β-d-thio galacto- and glucopyranosides and their 6S-deuterio isotopomers, with systematic variation of the protecting group at the 4-position, are described. For the galactopyranosides, replacement of a 4-O-benzyl ether by a 4-O-alkanoyl or aroyl ester results in a small but measurable shift in side chain population away from the trans,gauche conformation and in favor of the gauche,trans conformer. In the glucopyranoside series on the other hand, replacement of a 4-O-benzyl ether by a 4-O-alkanoyl or aroyl ester results in a small but measurable increase in the population of the trans,gauche conformer at the expense of the gauche,gauche conformer. The possible modulating effect of these conformational changes on the well-known changes in the anomeric reactivity of glycosyl donors as a function of protecting group is discussed, raising the possibility that larger changes may be observed at the transition state for glycosylation. A comparable study with a series of ethyl 2,3,4-tri-O-benzyl-β-d-thioglucopyranosides reveals that no significant influence in side chain population is observed on changing the O6 protecting group.
Organotin-catalyzed regioselective benzylation of carbohydrate trans-diols
Xu, Hengfu,Zhang, Ying,Dong, Hai,Lu, Yuchao,Pei, Yuxin,Pei, Zhichao
, p. 4039 - 4042 (2017/10/06)
A convenient approach to regioselective benzylation of carbohydrate trans-diols was developed, where 0.1 equiv. of Bu2SnCl2 and 0.1 equiv. of TBABr were used as the catalysts and 2.0 equiv. of BnCl was used as the benzylation reagent. In most cases, similar or better benzylation regioselectivities and isolated yields were obtained by using catalytic amounts of Bu2SnCl2, rather than stoichiometric amounts of organotin reagents required.
Directing effect by remote electron-withdrawing protecting groups at O-3 or O-4 position of donors in glucosylations and galactosylations
Baek, Ju Yuel,Kwon, Hea-Won,Myung, Se Jin,Park, Jung Jun,Kim, Mi Young,Rathwell, Dominea C.K.,Jeon, Heung Bae,Seeberger, Peter H.,Kim, Kwan Soo
supporting information, p. 5315 - 5320 (2015/07/15)
Glucosylations and galactosylations of various acceptors with donors possessing an electron-withdrawing benzylsulfonyl, benzoyl, or acetyl group at the O-3 or O-4 position were performed. A β-directing effect by the benzylsulfonyl group at O-3 of the glucosyl donors and by the benzylsulfonyl and acyl groups at O-4 of the glucosyl donors was observed. In contrast, acyl groups at O-3 of the glucosyl donors and acyl groups at O-3 and O-4 of the galactosyl donors exhibited an α-directing effect. The α-directing effect is partly considered to remote participation of the acyl groups, whereas the β-directing effect is somewhat attributed to the SN2-like reaction of the acceptor with the glycosyl triflate or the contact ion pair, which is stabilized by remote electron-withdrawing groups. Further evidence for the stability of the α-glycosyl triflates was determined by a low-temperature NMR study.
HClO4-silica-catalysed regioselective opening of benzylidene acetals and its application towards regioselective HO-4 glycosylation of benzylidene acetals in one-pot
Dara, Saidulu,Saikam, Varma,Yadav, Mahipal,Singh, Parvinder Pal,Vishwakarma, Ram A.
supporting information, p. 93 - 96 (2014/05/20)
Here we report a high-yielding method for the regioselective reductive ring opening of 4,6-O-benzylidene acetals of hexapyranosides using inexpensive and robust HClO4-SiO2 as the acidic catalyst and triethylsilane as the hydride dono
Synthesis of oligo(α- d -glycosyl phosphate) derivatives by a phosphoramidite method via boranophosphate intermediates
Fujita, Shoichi,Oka, Natsuhisa,Matsumura, Fumiko,Wada, Takeshi
supporting information; experimental part, p. 2648 - 2659 (2011/06/20)
An efficient method for the synthesis of short oligo(α-d-glycosyl boranophosphate) derivatives by using an α-d-glycosyl phosphoramidite as a monomer unit was developed. The synthesis of oligomers was carried out by repeating a cycle consisting of the cond
Synthesis and evaluation of 3″- and 4″-deoxy and -fluoro analogs of the immunostimulatory glycolipid, KRN7000
Raju, Ravinder,Castillo, Bernard F.,Richardson, Stewart K.,Thakur, Meena,Severins, Ryan,Kronenberg, Mitchell,Howell, Amy R.
supporting information; experimental part, p. 4122 - 4125 (2010/04/29)
Four 3″- and 4″-deoxy and -fluorogalactosyl ceramides were synthesized, and their ability to stimulate iNKT cells, based on levels of IL-2 production, was assessed in three NKT cell receptor hybridomas. In two of the hybridomas, 1.2 and 2H4, all of the analogs were immunostimulatory, while in the 1.4 hybridoma only the 4″-fluoro analog led to the production of significant levels of IL-2.
Single-step multisyntheses of glycosyl acceptors: Benzylation of n-1 hydroxyl groups of phenylthio glycosides of xylose, mannose, glucose, galactose, 2-azido-2-deoxy-glucose, and 2-azido-2-deoxy-galactose
Suzuki, Kaori,Ohtsuka, Isao,Kanemitsu, Takuya,Ako, Takuro,Kanie, Osamu
, p. 219 - 236 (2007/10/03)
An array of synthons is required to access an oligosaccharide library; however, multistep and thus time-consuming synthesis is inevitable. To rapidly access such synthetic units, multiple benzylation reactions of monosaccharides under phase-transfer condi
The synthesis of deoxy-α-Gal epitope derivatives for the evaluation of an anti-α-Gal antibody binding
Janczuk, Adam J.,Zhang, Wei,Andreana, Peter R.,Warrick, Joshua,Wang, Peng G.
, p. 1247 - 1259 (2007/10/03)
α-Gal epitopes (also termed as α-Gal) are carbohydrate structures bearing the α-D-Gal-(1→3)-β-D-Gal terminus 1 and are known to be the antigen responsible for antibody-mediated hyperacute rejection in xenotransplantation. Terminal 2-, 3-, 4-, and 6-deoxy-Gal derivatives of α-Gal were synthesized. Inhibition ELISA using mouse laminin was established to determine the binding affinity of the synthesized α-Gal derivatives. 4-Deoxy-α-Gal derivative 7 showed a significant reduction in antibody recognition. The IC50 value was 15-fold poorer than the standard α-Gal epitopes α-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Glc-NHAc (39) and α-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Glc-OBn (40). A similar observation was seen with 2-deoxy-α-Gal derivative 5, whose IC50 value was nearly tenfold higher than the standards. Interestingly, substitution at the terminal 3-position resulted in only a fourfold decrease in antibody recognition, suggesting a possible point of future derivation. Finally, 6-deoxy-α-Gal derivative 8 exhibited similar antibody recognition to both α-Gal epitope 39 and α-Gal epitope 40. This strongly suggests that derivatization at the 6-position can be accomplished without loss of antibody recognition. These findings can be utilized for the future design of other α-Gal derivatives.
Chemical synthesis of 6'-α-maltosyl-maltotriose, a branched oligosaccharide representing the branch point of starch
Motawia,Olsen,Enevoldsen,Marcussen,Moller
, p. 109 - 123 (2007/10/02)
Chemical synthesis of the branched pentasaccharide 6'-α-maltosyl-maltotriose (15) is reported, based on the use of one synthon as a glycosyl acceptor and another synthon as a glycosyl donor. The synthon used as glycosyl acceptor was phenyl 2,3,6-tri-O-benzyl-1-thio-β-D-glucopyranoside (7) and was synthesized from D-glucose with phenyl 2,3-di-O-acetyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside and phenyl 2,3-di-O-benzyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside as key intermediates. The synthon used as glycosyl donor was O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl)-(1 → 4)-O-(2,3,6-tri-O-benzyl-α-D-glucopyranosyl)-(1 → 6)-O-[(2,3,4,6-tetra-O-benzylα-D-glucopyranosyl)-(1 → 4)]-2,3-di-O-benzyl-α,β-D-glucopyranosyl trichloroacetimidate (12) and was synthesized from phenyl O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl)-(1 → 4)-O-(2,3,6-tri-O-benzyl-α-D-glucopyranosyl)-(1 → 6)-O-[(2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl)(1 → 4)]-2,3-di-O-acetyl-1-thio-β-D-glucopyranoside with O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl)-(1 → 4)-O-(2,3,6-tri-O-benzyl-α-D-glucopyranosyl)-(1 → 6)-O-[(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl)-(1 → 4)]-2,3-di-O-benzyl-D-glucopyranose as an intermediate. Condensation of compounds 7 and 12 followed by removal of the phenylthio group and debenzylation provided the branched pentasaccharide 15. Alternatively, the branched pentasaccharide was produced from amylopectin by consecutive alpha- and beta-amylase treatments and purified by chromatography. The identity of the products obtained by chemical synthesis and enzymatic hydrolysis is documented by 1H and 13C NMR spectra.
