- Improved synthesis of 1-O-acyl-β-D-glucopyranose tetraacetates
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An improved synthesis of 1-O-acyl glucosyl esters that avoids the use of expensive Ag reagents as well as the hydrolysis of unstable glucosyl bromides is reported. Notably, β-configuration products were obtained exclusively in good yields.
- Chen, Yu,Lu, Huan,Chen, Yanyu,Yu, Wansheng,Dai, Hui,Pan, Xianhua
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- Reversing Reactivity: Stereoselective Desulfurative 1,2- trans- O-Glycosylation of Anomeric Thiosugars with Carboxylic Acids under Copper or Cobalt Catalysis
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We have discovered a new mode of reactivity of 1-thiosugars in the presence of Cu(II) or Co(II) for a stereoselective O-glycosylation reaction. The process involves the use of a catalytic amount of Cu(acac)2 or Co(acac)2 and Ag2CO3 as an oxidant in α,α,α-trifluorotoluene. Moreover, this protocol turned out to have a broad scope, allowing the preparation of a wide range of complex substituted O-glycoside esters in good to excellent yields with an exclusive 1,2-trans-selectivity. The late-stage modification of pharmaceuticals by this method was also demonstrated. To obtain a closer insight into the reaction mechanism, cyclic voltammetry was performed.
- Bennai, Nedjwa,Chabrier, Amélie,Fatthalla, Maha I.,Tran, Christine,Yen-Pon, Expédite,Belkadi, Mohamed,Alami, Mouad,Grimaud, Laurence,Messaoudi, Samir
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supporting information
p. 8893 - 8909
(2020/08/14)
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- Synthesis of some monosaccharide-related ester derivatives as insecticidal and acaricidal agents
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To develop natural-product-based pesticidal agents, a series of monosaccharide-related ester derivatives (17a–q and 18a–f), glucose (xylose)-piperic acid/piperic acid-like conjugates, were synthesized. Three-dimensional structures of compounds 17b, 17g, 17h, and 17n were unambiguously determined by single-crystal X-ray diffraction. Especially compounds 18e and 18f exhibited the most potent insecticidal and acaricidal activities against Mythimna separata and Tetranychus cinnabarinus. Their structure-activity relationships were also discussed.
- Huang, Xiaobo,Zhang, Bingchuan,Xu, Hui
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p. 4336 - 4340
(2017/09/12)
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- Synthesis of various β-D-glucopyranosyl and β-Dxylopyranosyl hydroxybenzoates and evaluation of their antioxidant activities
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Various β-D-glucopyranosyl and β-Dxylopyranosyl hydroxybenzoates were efficiently prepared from 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (TAGB) or 2,3,4-tri-O-acetyl-α-D-xylopyranosyl bromide (TAXB), respectively, by amine-promoted glycosylation.
- Shimotori, Yasutaka,Hoshi, Masayuki,Osawa, Yosuke,Miyakoshi, Tetsuo
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p. 213 - 223
(2017/07/22)
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- Polyvinyl trisulfonate ethylamine based solid acid catalyst for the efficient glycosylation of sugars under solvent free conditions
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Heterogeneous Bronsted solid acid catalysts have the potential to decrease the environmental impact related to chemical production. Herein, we have synthesized polyvinyl bound trisulfonate ethylamine chloride (PV-THEAC) and polyvinyl bound disulfonate ethylamine (PV-DSEA) as Bronsted solid acid catalysts which exhibited effective catalytic activity for acid catalyzed glycosylation reactions with sugar derivatives. In particular, 0.3 equiv. of the PV-THEAC catalyst was found to be the most efficient and a reusable catalyst for glycosylation reactions. A high density of the trisulfonic group (-OSO3H) contributed to the excellent catalytic activity during glycosylation. Moreover, glycosylation reactions with d-mannose, d-xylose and d-glucose have been studied with alcohol. Remarkable acceleration of the glycosylation reaction using a glycosyltrichloroacetimidate donor was obtained with the selective production of β-glycoside.
- Chaugule, Avinash A.,Jadhav, Amol R.,Kim, Hern
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p. 104715 - 104724
(2015/12/30)
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- Highly efficient β-glucosylation of the acidic hydroxyl groups, phenol and carboxylic acid, with an peracetylated glucosyl fluoride using a combination of BF3·Et2O and DTBMP as a promoter
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A combination of BF3·Et2O and DTBMP was established to be an efficient promoter of β-glucosylation of both phenols and carboxylic acids with a peracetylated glucosyl fluoride (2). This new method achieved remarkably high yields and β
- Oyama, Kin-Ichi,Kondo, Tadao
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p. 1627 - 1629
(2007/10/03)
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- Phyllanthoside-Phyllanthostatin Synthetic Studies. 8. Total Synthesis of (+)-Phyllanthoside. Development of the Mitsunobu Glycosyl Ester Protocol
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The first total syntheses of the antineoplastic glycoside (+)-phyllanthoside (1) and the parent disaccharide (-)-phyllanthose (5) have been achieved. Stereoselective Koenigs-Knorr coupling of two 6-deoxyglucose derivatives, bromide 54 and alcohol 55, generated the uncommon 1′ → 2β glycosidic linkage of (-)-phyllanthose. A stereochemically convergent Mitsunobu reaction of protected disaccharide 87 with aglycon carboxylic acid 80, prepared via asymmetric synthesis, then led to 1 of high enantiomeric purity. The Mitsunobu procedure comprises an efficient general method for stereospecific assembly of β-glycosyl esters.
- Smith III, Amos B.,Rivero, Ralph A.,Hale, Karl J.,Vaccaro, Henry A.
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p. 2092 - 2112
(2007/10/02)
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- Studies of Carbohydrates IV. A Novel Highly Stereoselective Synthesis of 1-O-Acyl-β-D-glucopyranose Tetraacetates via the Glucosyl Trifluoroacetate
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2,3,4,6-Tetra-acetyl-glucose (1) reacted with trifluoroacetic anhydride to give good yield of 2,3,4,6-tetra-O-acetyl-1-α-O-trifluoroacetyl-α-D-glucopyranose (2) wich was converted into corresponding 1-O-acyl-β-D-glucopyranose tetraacetates. β-Anomers of g
- Yu, Cheng-Fang,Li, Zhan-Jiang,Cai, Meng-Shen
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p. 943 - 948
(2007/10/02)
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- 2-(Trimethylsilyl)ethyl Glycosides. Synthesis, Anomeric Deblocking, and Transformation into 1,2-Trans 1-O-Acyl Sugars
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Twenty-seven mono --> tetrasaccharidic 2-(trimethylsilyl)ethyl (TMSET) glycosides were synthesized by the Koenigs-Knorr-type method in combination with a wide range of standard reagents for glycoside synthesis and protecting-group chemistry.Variously protected TMSET glycosides were treated with BF3*Et2O (0.7-0.8 equiv) and different carboxylic anhydrides (1.1-15 equiv) in toluene at 22-55 deg C, which gave in one step the corresponding protected 1-O-acyl sugars.In the majority of cases, the yields of purified compounds exceeded 90percent and the anomeric configuration of the starting TMSET glyoside was conserved to a large extent (>95percent) in most of the 1-O-acylated products.Unprotected and acetyl-, benzoyl-, benzyl-, dimethyl-tert-butylsilyl-, and phthaloyl-protected mono-->tetrasaccharidic TMSET glycosides were anomerically deblocked by using trifluoroacetic acid in dichloromethane at 0-22 deg C for 10-30 min.The hemiacetal products were isolated in 88-96percent yield; all reagents and byproducts were volatile and easily removed.
- Jansson, Karl,Ahlfors, Stefan,Frejd, Torbjoern,Kihlberg, Jan,Magnusson, Goeran,et al.
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p. 5629 - 5647
(2007/10/02)
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- POLYMER SUPPORTED SYNTHESIS OF 2,3,4,6-TETRA-O-ACETYL-β-D-GLUCOPYRANOSYL ESTERS OF AROMATIC CARBOXYLIC ACIDS
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Aromatic carboxylic acids bound to Amberlyst A-26 react with α-acetobromoglucose to form 2,3,4,6-tetra-O-acetyl-1-O-aroyl-β-D-glucopyranose derivatives in good yield.Glucosylation occurs satisfactory with carboxylic acids and nitrophenols (pKa 7-4), but not with phenols whose pKa values higher (pKa ca 10).Selective glucosylation at the carboxylic group is easily achieved in the case of phenolic acids.
- Krishnamurty, H. G.,Dabholkar, Kavita,Maheshwari, Nitin
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p. 1323 - 1330
(2007/10/02)
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- AN EFFICIENT SYNTHESIS OF GLYCOSYL ESTERS EXPLOITING THE MITSUNOBU REACTION.
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The anomeric hydroxyl group of various pyranose hemiacetals can be esterified with inversion of configuration, conveniently, mildly and on large-scale using triphenylphosphine (TPP), with either diisopropylazodicarboxylate (DIAD) or diethylazodicarboxylat
- Smith III, Amos B.,Hale, Karl J.,Rivero, Ralph A.
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p. 5813 - 5816
(2007/10/02)
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