29019-41-8Relevant academic research and scientific papers
Concise Synthesis of 1-Thioalkyl Glycoside Donors by Reaction of Per-O-acetylated Sugars with Sodium Alkanethiolates under Solvent-Free Conditions
Feng, Guang-Jing,Luo, Tao,Guo, Yang-Fan,Liu, Chun-Yang,Dong, Hai
, p. 3638 - 3646 (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.
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.
Reengineering Chemical Glycosylation: Direct, Metal-Free Anomeric O-Arylation of Unactivated Carbohydrates
Lucchetti, Nicola,Gilmour, Ryan
supporting information, p. 16266 - 16270 (2018/10/24)
To sustain innovation in glycobiology, effective routes to well-defined carbohydrate probes must be developed. For over a century, glycosylation has been dominated by the formation of the anomeric Csp3?O acetal junction in glycostructures. A dissociative mechanistic spectrum spanning SN1 and SN2 is frequently operational thereby reducing the efficiency. By reengineering this fundamental process, an orthogonal disconnection allows the acetal to be formed directly from the reducing sugar without the need for substrate pre-functionalisation. The use of stable aryliodonium salts facilitates a formal O?H functionalisation reaction. This allows lactols to undergo mild, metal-free O-arylation at ambient temperature. The efficiency of the transformation has been validated using a variety of pyranoside and furanoside monosaccharides in addition to biologically relevant di- and trisaccharides (up to 85 %). Fluorinated mechanistic probes that augment the anomeric effect were employed. It is envisaged that this strategy will prove expansive for the construction of complex acetals under substrate-based stereocontrol.
A facile and efficient method for the one-pot synthesis of per-O-acetylated thioglycosides from unprotected sugars
Yan, Shiqiang,Ding, Ning,Zhang, Wei,Wang, Peng,Li, Yingxia,Li, Ming
, p. 571 - 583 (2012/10/30)
An efficient, convenient protocol for the preparation of per-O-acetylated p-tolylthio glycosides is described. Treatment of various unprotected sugars, including 2-deoxy-2-amino sugars, sialic acid, lactose, and maltose, with acetic anhydride using SnCl4 as a catalyst, and subsequently with p-tolylthiol, furnished the corresponding thioglycosides in 71%-90% yield under solvent-free conditions.
Chemoselective deacylation of functionalized esters catalyzed by dioxomolybdenum dichloride
Liu, Cheng-Yuan,Chen, Hui-Ling,Ko, Chih-Min,Chen, Chien-Tien
scheme or table, p. 872 - 876 (2011/03/19)
Among five different oxidometallic species and two Lewis acids investigated, MoO2Cl2 shows the best catalytic and chemoselective activity for the deacylation of esters in methanol at ambient or elevated temperature. Both high efficiency and chemoselectivity were achieved for substrates bearing different ether or ester groups. Acylated mono and disaccharides can also be selectively deacetylated in good yields, leading to useful carbohydrate templates for further synthetic manipulations.
Solvent-free synthesis of thioglycosides by ball milling
Ramrao Patil, Premanand,Ravindranathan Kartha
experimental part, p. 953 - 956 (2010/04/23)
Thioglycosides have been prepared in excellent yields by three different routes from a range of readily available glycosyl halides under solvent-free conditions employing a planetary ball mill.
Low-concentration 12-trans β-selective glycosylation strategy and its applications in oligosaccharide synthesis
Chao, Chin-Sheng,Li, Chen-Wei,Chen, Min-Chun,Chang, Shih-Sheng,Mong, Kwok-Kong Tony
supporting information; experimental part, p. 10972 - 10982 (2010/04/30)
This study develops an operationally easy, efficient, and general 1,2-trans β-selective glycosylation reaction that proceeds in the absence of a C2 acyl function. This process employs chemically stable thioglycosyl donors and low substrate concentrations to achieve excellent β-selectivities in glycosylation reactions. This method is widely applicable to a range of glycosyl substrates irrespective of their structures and hydroxyl-protecting functions. This low-concentration 1,2-trans β-selective glycosylation in carbohydrate chemistry removes the restriction of using highly reactive thioglycosides to construct 1,2-trans β-glycosidic bonds. This is beneficial to the design of new strategies for oligosaccharide synthesis, as illustrated in the preparation of the biologically relevant β-(1-6)-glucan trisaccharide, β-linked Gb3 and isoGb3 derivatives.
Lanthanum trifluoromethane-sulfonate-catalyzed facile synthesis of per-O-acetylated sugars and their one-pot conversion to S-aryl and O-alkyl/aryl glycosides
Dasgupta, Somnath,Rajput, Vishal Kumar,Roy, Bimalendu,Mukhopadhyay, Balaram
, p. 91 - 106 (2008/02/09)
Lanthanum trifluoromethanesulfonate-catalyzed solvent-free per-O-acetylation with stoichiometric acetic anhydride proceeds in high yield (95%-99%) to afford exclusively pyranose products as anomeric mixtures. Subsequent anomeric substitution employing borontrifluoride etherate and thiols or alcohols furnished the corresponding 1,2-trans-linked thioglycosides and O-glycosides, respectively, in good to excellent overall yield (75%-85%). Alternatively, reaction of free sugars in neat alcohol employing the same catalyst at elevated temperature gives the corresponding 1,2-cis-linked O-glycosides (along with 1,2-trans-linked glycosides as minor product) in good yield (73%-80%). Anomeric mixtures of compounds thus produced were characterized as their per-O-acetylated derivatives.
Large-scale synthesis of per-O-acetylated saccharides and their sequential transformation to glycosyl bromides and thioglycosides
Lin, Chan-Ching,Huang, Li-Cheng,Liang, Pi-Hui,Liu, Ching-Yang,Lin, Chun-Cheng
, p. 303 - 313 (2007/10/03)
This work describes a large-scale synthesis of per- O -acetylated mono- and disaccharides using a stoichiometric amount of acetic anhydride in the presence of LiClO 4 under solvent-free conditions. The peracetylated saccharides underwent subsequent anomeric bromination and thioglycosidation in one-pot to yield synthetically valuable building blocks. Copyright Taylor & Francis Group, LLC.
Stereoselective syntheses of 1,2-trans p-MePh and 2-pyridyl 1- thioglycosides catalyzed by zirconium(IV) chloride
Ding, Yili
, p. 3541 - 3546 (2007/10/03)
1-Thioglycosides including per-O-acetyl p-MePh and 2-pyridyl 1- thioglycosides were chemically synthesized with high complete stereoselectivity by using ZrCl4 as catalyst.
