167084-05-1Relevant academic research and scientific papers
Synthesis of triazolyl-linked polysialic acids
Xiong, De-Cai,Zhou, Yichuan,Cui, Yuxin,Ye, Xin-Shan
, p. 9405 - 9412 (2014)
A new approach for the synthesis of triazolyl-linked α-(2-9) oligosialic acids by iterative copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) and desilylation has been developed. By using propargyl α-sialoside 5 and trimethylsilylated-propargyl 9-azido-α-sialoside 3 as building blocks, triazolyl-linked α-(2-9) di- to octa-sialic acids were constructed in good to moderate yields. Finally, the pseudo-α-(2-9)-oligosialic acids were obtained very smoothly via O-deprotection. The oligosialic acids with a triazolyl-linkage represent a new type of pseudooligosialic acids. This protocol may find applications in the preparation of oligosialic acid analogues with biological importance.
Concise Synthesis of 1-Thioalkyl Glycoside Donors by Reaction of Per-O-acetylated Sugars with Sodium Alkanethiolates under Solvent-Free Conditions
Dong, Hai,Feng, Guang-Jing,Guo, Yang-Fan,Liu, Chun-Yang,Luo, Tao
, (2022/02/07)
A relatively green method for synthesizing 1-thioalkyl glycosides has been developed, where sodium alkanethiolates were used to react with per-O-acetylated sugars instead of odorous alkyl mercaptans in the presence of BF3·Et2O without the use of solvents under mild conditions. Furthermore, we found that 1,2-trans-β-thioglycosides can be converted into corresponding 1,2-cis-α-thioglycosides in the presence of trifluoromethanesulfonic acid in nonpolar solvents under mild conditions. This provides a simple and efficient new approach for synthesizing challenging 1,2-cis-α-thioglycosides.
Donor-Reactivity-Controlled Sialylation Reactions
Asressu, Kesatebrhan Haile,Chang, Chun-Wei,Lam, Sarah,Wang, Cheng-Chung
supporting information, p. 4525 - 4530 (2021/08/09)
Although tremendous efforts have been made for the efficient preparation of sialosides, controlling the stereochemical outcome of sialylation reaction still remains one of the most challenging tasks due to the unique chemical structure of sialic acid. We developed a new strategy to statistically analyze the stereoselectivity of sialylation reactions on six types of p-tolyl thiosialosides in NIS/TfOH system using Relative Reactivity Value (RRV) as the indicator. Analysis of the reaction mechanism showed the formation of the relatively stable glycosyl bromide and glycosyl chloride intermediates from halide- and triflate-containing promotors in the absence of an acceptor. We found that the α/β-stereoselectivity, yields, and intermediate changes were associated with their donor reactivity. These findings enable to tailor the most suitable building blocks for stereo-controlled sialylation reactions.
Triflic acid-mediated synthesis of thioglycosides
Escopy, Samira,Singh, Yashapal,Demchenko, Alexei V.
supporting information, p. 8379 - 8383 (2019/09/30)
An efficient synthesis of thioglycosides from per-acetates in the presence of triflic acid is described. The developed protocol features high reaction rates and product yields. Some reactive sugar series give high efficiency in the presence of sub-stoichiometric trifluoromethanesulfonic acid (TfOH) in contrast to other known protocols that require multiple equivalents of Lewis acids to reach high conversion rates.
NOVEL NEISSERIA MENINGITIDIS SEROGROUP Y OLIGOMER AND PROCESS FOR SYNTHESIZING THEREOF
-
Page/Page column 12; 15; 16, (2017/02/24)
The present invention relates to novel oligomers of Neisseria meningitidis serogroup Y capsular polysaccharide repeating unit (Men-Y oligomers) and process for synthesizing novel Men- Y oligomers. In particular, the present invention relates to the chemic
Comparative studies on the O-sialylation with four different α/β-oriented (N-acetyl)-5-N,4-O-carbonyl-protected p-toluenethiosialosides as donors
Zhang, Xiao-Tai,Gu, Zhen-Yuan,Xing, Guo-Wen
, p. 1 - 7 (2014/03/21)
Four types of 5-N,4-O-carbonyl-protected p-toluenethiosialosides were synthesized and their couplings with different acceptors were thoroughly investigated. The results indicate that the sialyl donor structure, the amount of glycosyl acceptor, and the detailed promotion conditions have great influence on the sialylation stereoselectivties and product yields. Under the (p-Tol)2SO/Tf2O activation conditions, the glycosylations with simple alcohols provided declined α-selectivities and higher yields with increasing the amounts of acceptors from 1.1 equiv to 2.0 equiv. However, the outcome of same sialylation was independent of the relative amounts of sugar alcohol acceptors. With NIS/TfOH as promoter, the α-selectivities of the sialylations were significantly improved compared with the cases activated by (p-Tol)2SO/Tf2O. In general, the difference in configuration of N-acetylated sialyl donors (D2 and D4) has little effect on the sialylation yield and stereoselectivity. In contrast, the N-deacetylated α/β sialyl donors (D1 and D3) show complex sialylation profiles with different acceptors.
An efficient approach for total synthesis of aminopropyl functionalized ganglioside GM1b
Sun, Bin,Jiang, Heyan
, p. 5711 - 5715 (2012/11/13)
A highly efficient protocol for the synthesis of aminopropyl functionalized ganglioside GM1b has been described. The full protected ganglioside GM1b was obtained in 71% yield within 5 h. The key feature of the synthetic approach was the use of sialic acid
Conversion of the carboxy group of sialic acid donors to a protected hydroxymethyl group yields an efficient reagent for the synthesis of the unnatural beta-linkage
Ye,Huang,Wong
, p. 974 - 975 (2007/10/03)
New sialyl donors with a protected hydroxymethyl group at the anomeric center are over 1000 times more reactive than the normal ester containing sialylation reagent and give excellent yield (> 90%) with unusually high β-stereoselectivity in sialylation.
The thioglycoside and glycosyl phosphite of 5-Azido sialic acid: Excellent donors for the α-glycosylation of primary hydroxy groups
Yu, Chung-Shan,Niikura, Kenichi,Lin, Chun-Cheng,Wong, Chi-Huey
, p. 2900 - 2903 (2007/10/03)
5-Azido sialyl donors with O-acetyl protecting groups are useful α-selective glycosylation reagents, especially for primary hydroxyl groups as acceptors. This is shown with a variety of reactions using 1 as a sialyl donor. It was also possible to synthesi
Microbial glycosyltransferases for carbohydrate synthesis: α-2,3-sialyltransferase from Neisseria gonorrheae
Izumi,Shen,Wacowich-Sgarbi,Nakatani,Plettenburg,Wong
, p. 10909 - 10918 (2007/10/03)
The α-2,3-sialyltransferase from Neisseria gonorrheae was overproduced in E. coli for exploitation of its substrate specificity and synthetic utility. Several potential acceptor substrates were synthesized in this study, including mono- and oligosaccharid
