40593-10-0Relevant academic research and scientific papers
Metal-catalyzed stereoselective and protecting-group-free synthesis of 1,2-cis-glycosides using 4,6-dimethoxy-1,3,5-triazin-2-yl glycosides as glycosyl donors
Tanaka, Tomonari,Kikuta, Naoya,Kimura, Yoshiharu,Shoda, Shin-Ichiro
, p. 846 - 848 (2015)
4,6-Dimethoxy-1,3,5-triazin-2-yl glycosides, glycosyl donors prepared in one step from free saccharides without protection of the hydroxy groups, were stereoselectively and equivalently converted to the corresponding 1,2-cis-glycosides by using a catalytic amount of metal catalyst. This reaction was successfully applied not only to monosaccharides, but also to di- and oligosaccharides.
Selective C?O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers’ Borane Generated In Situ
Zhang, Jianbo,Park, Sehoon,Chang, Sukbok
supporting information, p. 13757 - 13761 (2017/10/09)
Described herein is the selective reduction of sugars with hydrosilanes catalyzed by using Piers’ borane [(C6F5)2BH] generated in situ. The hydrosilylative C?O bond cleavage of silyl-protected mono- and disaccharides in the presence of a (C6F5)2BH catalyst, generated in situ from (C6F5)2BOH, takes place with excellent chemo- and regioselectivities to provide a range of polyols. A study of the substituent effects of sugars on the catalytic activity and selectivity revealed that the steric environment around the anomeric carbon (C1) is crucial.
Direct glycosylation of bioactive small molecules with glycosyl iodide and strained olefin as acid scavenger
Gu, Xiangying,Chen, Lin,Wang, Xin,Liu, Xiao,You, Qidong,Xi, Wenwei,Gao, Li,Chen, Guohua,Chen, Yue-Lei,Xiong, Bing,Shen, Jingkang
, p. 1100 - 1110 (2014/03/21)
A new strategy for diversity-oriented direct glycosylation of bioactive small molecules was developed. This reaction features (-)-β-pinene as acid scavenger and work with glycosyl iodides under mild conditions. With the aid of RP-HPLC and chiral SFC separation techniques, the new direct glycosylation proved effective at gram scale on bioactive small molecules including AZD6244, podophyllotoxin, paclitaxel, and docetaxel. Interesting glycoside derivatives were efficiently created with good yields and 1,2-cis selectivity.
Protection-free synthesis of alkyl glycosides under hydrogenolytic conditions
Ishihara, Masaki,Takagi, Yuka,Li, Gefei,Noguchi, Masato,Shoda, Shin-Ichiro
supporting information, p. 1235 - 1237 (2013/10/22)
A convenient protection-free synthetic route for the preparation of alkyl glycosides has been developed. The alcoholysis of one-step preparable glycosyl donors, 4,6-dibenzyloxy-1,3,5-triazin-2-yl (DBT) glycosides, under hydrogenolytic conditions gave the corresponding glycosides in good yields without the addition of any acid promoters. The method could be successfully applied to the glycosylation of an acidlabile oligosaccharide.
Isolation and characterization of a novel α-glucosidase with transglycosylation activity from Arthrobacter sp. DL001
Zhou, Kun,Luan, Hong-Wei,Hu, Ying,Ge, Guang-Bo,Liu, Xing-Bao,Ma, Xiao-Chi,Hou, Jie,Wang, Xiu-Li,Yang, Ling
experimental part, p. 48 - 57 (2012/09/07)
A strain of Arthrobacter sp. DL001 with high transglycosylation activity was successfully isolated from the Yellow Sea of China. To purify the extracellular enzyme responsible for transglycosylation, a four-step protocol was adopted and the enzyme with electrophoretical purity was obtained. The purified enzyme has a molecular mass of 210 kDa and displays a narrow hydrolysis specificity towards α-1,4-glucosidic bond. Its hydrolytic activity was identified as decreasing in the order of maltotriose > panose > maltose. Only 3.61% maltose activity occurs when p-nitrophenyl α-d-glycopyranoside serves as a substrate, suggesting that this enzyme belongs to the type II α-glucosidase. In addition, the enzyme was able to transfer glucosyl groups from the donors containing α-1,4-glucosidic bond specific to glucosides, xylosides and alkyl alcohols in α-1,4- or α-1,6-manners. A decreased order of activity was observed when maltose, maltotriose, panose, β-cyclodextrin and soluble starch served as glycosyl donors, respectively. When maltose was utilized as a donor and a series of p-nitrophenyl-glycosides as acceptors, the glucosidase was capable of transferring glucosyl groups to p-nitrophenyl-glucosides and p-nitrophenyl-xylosides in α-1,4- or α-1,6-manners. The yields of p-nitrophenyl-oligosaccharides could reach 42-60% in 2 h. When a series of alkyl alcohols were utilized as acceptors, the enzyme exhibited its transglycosylation activities not only to the primary alcohols but also to the secondary alcohols with carbon chain length 1-4. Therefore, all the results indicated that the purified α-glucosidase present a useful tool for the biosynthesis of oligosaccharides and alkyl glucosides.
Efficient glycosylation of unprotected sugars using sulfamic acid: A mild eco-friendly catalyst
Guchhait, Goutam,Misra, Anup Kumar
experimental part, p. 52 - 57 (2012/01/15)
Sulfamic acid, a mild and environmentally benign catalyst has been successfully used in the Fischer glycosylation of unprotected sugars for the preparation alkyl glycosides. A diverse range of aliphatic alcohols have been used to prepare a series of alkyl glycosides in good to excellent yield.
Site-selective catalysis of phenyl thionoformate transfer as a tool for regioselective deoxygenation of polyols
Sanchez-Rosello, Maria,Puchlopek, Angela L. A.,Morgan, Adam J.,Miller, Scott J.
, p. 1774 - 1782 (2008/09/18)
(Chemical Equation Presented) We report the application of peptide-embedded imidazoles as catalysts for the site-selective delivery of the phenyl thionoformate unit as a prelude to deoxygenation reactions of polyols. Methodology was developed that allows for the synthesis of thiocarbonyl derivatives based on a combination of additives that include N-alkylimidazoles and FeCl3 as co-catalysts. The use of this reagent combination leads to increased reaction rates and efficient yields relative to those of simple base-mediated reactions. In terms of controlling regioselectivity during the course of polyol modification, we found that histidine-containing peptides, in combination with FeCl3, could lead to modulation of the product distribution. Through screening of peptides and control of reaction conditions, products could be observed that reflected both the inherent preference of substrates and also reversal of inherent selectivity.
1,2-ACYLSPIROORTHOESTERS OF 3,4,6-TRI-O-ACETYL-α-D-GLUCOPYRANOSE
Lemieux, Raymond U.,Hindsgaul, Ole
, p. 195 - 206 (2007/10/02)
The 1,2-O-(2-oxa-3-oxocyclopentylidene) derivative of 3,4,6-tri-O-acetyl-α-D-glucopyranose was prepared in both the exo (4) and endo (5) forms.The compounds were prepared by bromide-ion promoted cyclization of 3,4,6-tri-O-acetyl-2-O-(3-carboxypropanoyl)-α-D-glucopyranosyl bromide.The similar acylorthoester derivatives of phthalic acid were prepared from 3,4,6-tri-O-acetyl-2-O-(2-carboxybenzoyl)-α-D-glucopyranosyl bromide.The cyclizations produced a much higher ratio of the endo forms than would have been expected from their relative thermodynamic stabilities.The configurations were established by nuclear Overhauser enhancement studies and their conformations deduced from (1)H-n.m.r. parameters.The greater stability of the exo isomers appears to have a stereoelectronic origin.Preliminary efforts to engage the acylorthoesters in reactions with isopropyl alcohol to form glycosides are reported.It was discovered that a carboxylic acid provides powerful catalysis for the β to α anomerization of O-acetylatyed glucopyranosides by stannic chloride.
