53081-30-4Relevant articles and documents
A synthetic acceptor substrate for Trypanosoma brucei UDP-Gal : GPI anchor side-chain α-galactosyltransferases
Brown, Jillian R.,Smith, Terry K.,Ferguson, Michael A.J.,Field, Robert A.
, p. 2051 - 2054 (1998)
A synthetic analogue of a trisaccharide fragment of the Trypanosoma brucei Variant Surface Glycoprotein (VSG) GlycosylPhosphatidylInositiol (GPI) anchor, Gal-α-l,3(Man-α-1,6)-Man-α-O-octyl (1), serves as a substrate for two T. brucei α-galactosyltransfera
Synthesis of Glycosyl Chlorides and Bromides by Chelation Assisted Activation of Picolinic Esters under Mild Neutral Conditions
Balzer, Paul G.,Blaszczyk, Stephanie A.,Duan, Xiyan,Ma, Zhi-Xiong,Simmons, Christopher J.,Stevens, Christopher M.,Tang, Weiping,Wang, Hao-Yuan,Wen, Peng,Ye, Wenjing,Yin, Dan
supporting information, (2020/02/28)
A general method has been developed for the formation of glycosyl chlorides and bromides from picolinic esters under mild and neutral conditions. Benchtop stable picolinic esters are activated by a copper(II) halide species to afford the corresponding products in high yields with a traceless leaving group. Rare β glycosyl chlorides are accessible via this route through neighboring group participation. Additionally, glycosyl chlorides with labile protecting groups previously not easily accessible can be prepared.
Indolylthio glycosides as effective building blocks for chemical glycosylation
Demchenko, Alexei V.,Shrestha, Ganesh,Panza, Matteo,Singh, Yashapal,Rath, Nigam P.
, p. 15885 - 15894 (2021/01/19)
The S-indolyl (SIn) anomeric moiety was investigated as a new leaving group that can be activated for chemical glycosylation under a variety of conditions including thiophilic and metal-assisted pathways. Understanding of the reaction pathways for the SIn moiety activation was achieved via the extended mechanistic study. Also reported is how the new SIn donors fit into selective activation strategies for oligosaccharide synthesis.
Koenigs–Knorr Glycosylation Reaction Catalyzed by Trimethylsilyl Trifluoromethanesulfonate
Singh, Yashapal,Demchenko, Alexei V.
supporting information, p. 1461 - 1465 (2019/01/04)
The discovery that traditional silver(I)-oxide-promoted glycosidations of glycosyl bromides (Koenigs–Knorr reaction) can be greatly accelerated in the presence of catalytic trimethylsilyl trifluoromethanesulfonate (TMSOTf) is reported. The reaction conditions are very mild that allowed for maintaining a practically neutral pH and, at the same time, providing high rates and excellent glycosylation yields. In addition, unusual reactivity trends among a series of differentially protected glycosyl bromides were documented. In particular, benzoylated α-bromides were much more reactive than their benzylated counterparts under these conditions.
Establishment of Guidelines for the Control of Glycosylation Reactions and Intermediates by Quantitative Assessment of Reactivity
Chang, Chun-Wei,Wu, Chia-Hui,Lin, Mei-Huei,Liao, Pin-Hsuan,Chang, Chun-Chi,Chuang, Hsiao-Han,Lin, Su-Ching,Lam, Sarah,Verma, Ved Prakash,Hsu, Chao-Ping,Wang, Cheng-Chung
, p. 16775 - 16779 (2019/11/03)
Stereocontrolled chemical glycosylation remains a major challenge despite vast efforts reported over many decades and so far still mainly relies on trial and error. Now it is shown that the relative reactivity value (RRV) of thioglycosides is an indicator for revealing stereoselectivities according to four types of acceptors. Mechanistic studies show that the reaction is dominated by two distinct intermediates: glycosyl triflates and glycosyl halides from N-halosuccinimide (NXS)/TfOH. The formation of glycosyl halide is highly correlated with the production of α-glycoside. These findings enable glycosylation reactions to be foreseen by using RRVs as an α/β-selectivity indicator and guidelines and rules to be developed for stereocontrolled glycosylation.
β-Selective C-Glycosylation and its Application in the Synthesis of Scleropentaside A
Boehlich, G. Jacob,Schützenmeister, Nina
supporting information, p. 5110 - 5113 (2019/03/17)
C-Glycosides are carbohydrates that bear a C?C bond to an aglycon at the anomeric center. Due to their high stability towards chemical and enzymatic hydrolysis, these compounds are widely used as carbohydrate mimics in drug development. Herein, we report a general and exclusively β-selective method for the synthesis of a naturally abundant acyl-C-glycosidic structural motif first found in the scleropentaside natural product family. A Corey–Seebach umpolung reaction as the key step in the synthesis of scleropentaside A and analogues enables the β-selective construction of the anomeric C?C bond starting from unprotected carbohydrates in only four steps. The one-pot approach is highly atom-efficient and avoids the use of toxic heavy metals.
β-Selective One-Pot Synthesis of Acyl-C-Glycosides via Corey-Seebach Umpolung Reaction
Boehlich, G. Jacob,Schützenmeister, Nina
, p. 1935 - 1939 (2019/10/22)
C-Glycosides are commonly used as carbohydrate mimics in drug development due to their stability against enzymatic and chemical hydrolysis. In this Synpacts article we elaborate on our fast and efficient β-selective approach towards protected and unprotected acyl glycosides. Application of a Corey-Seebach umpolung reaction enables the exclusive formation of the β-Anomer of aromatic acyl-C-glycosides in good to excellent yields. 1 Introduction 2 C-Glycosylation of Benzylated Glycosyl Donors 3 C-Glycosylation of Silylated Glycosyl Donors 4 Conclusion.
Regenerative Glycosylation
Singh, Yashapal,Wang, Tinghua,Geringer, Scott A.,Stine, Keith J.,Demchenko, Alexei V.
, p. 374 - 381 (2018/01/01)
Previously, we communicated 3,3-difluoroxindole (HOFox)-mediated glycosylations wherein 3,3-difluoro-3H-indol-2-yl (OFox) imidates were found to be key intermediates. Both the in situ synthesis from the corresponding glycosyl bromides and activation of the OFox imidates could be conducted in a regenerative fashion. Herein, we extend this study to the synthesis of various glycosidic linkages using different sugar series. The main outcome of this study relates to enhanced yields and/or reduced reaction times of glycosylations. The effect of HOFox-mediated reactions is particularly pronounced in case of unreactive glycosyl donors and/or glycosyl acceptors. A multistep regenerative synthesis of oligosaccharides is also reported.
Gram scale synthesis of A (type 2) and B (type 2) blood group tetrasaccharides through 1,6-anhydro-N-acetyl-β-D-glucosamine
Tyrtysh, Tatiana V.,Korchagina, Elena Yu.,Ryzhov, Ivan M.,Bovin, Nicolai V.
, p. 65 - 84 (2017/07/26)
Gram scale synthesis of A (type 2) and B (type 2) tetrasaccharides in the form of 3-aminopropyl glycosides is proposed starting from 3-O-benzoyl-1,6-anhydro-N-acetylglucosamine. Its galactosylation followed by re-protection gave lactosamine derivative with single free 2′-OH group in total yield 75%. Standard fucosylation and next run of re-protection in total yield 88% gave a trisaccharide Fuc-Gal-anhydroGlcNAc with single free 3′-OH group. Its standard α-galactosylation gave protected B (type 2) tetrasaccharide. For synthesis of correspondent A tetrasaccharide seven different 2-azido-2-deoxygalactosyl (GalN3) donors were tested: 6-O-acetyl-3,4-O-isopropylidene-GalN3 thioglycoside was shown to provide the best yield (89%) and stereoselectivity (α/β = 24:1). Further 1,6-anhydro cycle opening, spacer-arming and complete deprotection resulted in the target 3-aminopropyl glycosides of A (type 2) and B (type 2) tetrasaccharides, yields 87 and 85% correspondingly.
Pyranoside-into-Furanoside Rearrangement of 4-Pentenyl Glycosides in the Synthesis of a Tetrasaccharide-Related to Galactan I of Klebsiella pneumoniae
Verkhnyatskaya, Stella A.,Krylov, Vadim B.,Nifantiev, Nikolay E.
, p. 710 - 718 (2017/02/05)
An efficient strategy for synthesis of a spacer-armed tetrasaccharide related to galactan I of Klebsiella pneumoniae is described, which uses newly developed acid-free conditions for the pyranoside-into-furanoside (PIF) rearrangement of a digalactoside bearing a 4-pentenyl group at the anomeric position. The 4-pentenyl aglycon was successfully used both as a leaving group in the glycosylation of 3-(trifluoroacetamido)propanol, and as a temporary anomeric protecting group, allowing conversion into an imidate donor. Regioselective coupling of the disaccharide blocks gave the desired tetrasaccharide sequence required for investigation of the interaction of galactan I with immune-system proteins.