- Thioglucose compound and preparation method thereof
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The invention provides a thioglucose compound which has the following general formula: Wherein R is selected from H or acetyl. The preparation method of the thioglucose compound is easy to obtain, low in production cost and suitable for industrial product
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Paragraph 0048-0050; 0052
(2021/09/22)
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- Ultrasound-assisted selective deprotection of terminal acetonides catalyzed by silica-supported boron trifluoride
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An efficient and convenient method for the selective cleavage of terminal acetonides is described. Treatment of terminal acetonides in the presence of a wide range of functional groups with silica-supported boron trifluoride as a catalyst furnished the corresponding diols in 82-95% yield under ultrasound irradiation conditions. The acid-labile p-methoxybenzyl group as a protecting group remained intact under the conditions employed to the present deprotection condition. Copyright Taylor & Francis Group, LLC.
- Xiong, Junlong,Yan, Shiqiang,Ding, Ning,Zhang, Wei,Li, Yingxia
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p. 184 - 192
(2013/07/27)
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- Catalytic asymmetric dihydroxylation of olefins using polysulfone-based novel microencapsulated osmium tetroxide
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A polysulfone based novel polymer-supported osmium catalyst has been developed. The catalyst was prepared from commercially available polysulfone, based on a microencapsulation technique and was employed in the asymmetric dihydroxylation of various olefins using (DHQD)2PHAL as the chiral ligand and NMO as the co-oxidant in H2O-acetone-CH3CN (1:1:1). The catalyst was recovered by simple filtration and was reused to obtain excellent yields with good enantioselectivity up to five times.
- Malla Reddy,Srinivasulu,Venkat Reddy,Narasimhulu,Venkateswarlu
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p. 5285 - 5288
(2007/10/03)
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- Mild, efficient, and selective cleavage of trityl ethers with antimony trichloride
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Selective detritylation is quite crucial in synthetic chemistry. A mild and efficient procedure for selective hydrolysis of trityl ethers in the presence of other frequently used hydroxy protecting groups: TBDPS, Bz, Bn, Ac and Ts with antimony trichloride was described and 5′-trityl uridine was detritylated smoothly too. Copyright Taylor & Francis Group, LLC.
- Wu, Qinpei,Wang, Yuan,Chen, Wei,Liu, Hua
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p. 1361 - 1366
(2007/10/03)
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- Sulfuric acid immobilized on silica: an efficient reusable catalyst for selective hydrolysis of the terminal O-isopropylidene group of sugar derivatives
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Sulfuric acid immobilized on silica proved to be an efficient catalyst for selective hydrolysis of the terminal O-isopropylidene group of sugar derivatives. The method is very simple and economic for large-scale synthesis in which the catalyst is recovered and reused for several runs. Reactions with di-O-isopropylidene derivatives of d-glucose, d-mannose, d-fructose and l-sorbose led to the formation of the corresponding mono-O-isopropylidene derivatives in good to excellent yields.
- Rajput, Vishal Kumar,Roy, Bimalendu,Mukhopadhyay, Balaram
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p. 6987 - 6991
(2007/10/03)
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- Selective deprotection of terminal isopropylidene acetals and trityl ethers using HClO4 supported on silica gel
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Terminal isopropylidene acetals are selectively cleaved to the corresponding 1,2-diols in good to excellent yields in 6-24 h at room temperature by using the 'HClO4?SiO2' reagent system. Likewise, trityl ethers are readily cleaved to the corresponding alcohols in good to excellent yields within 2-3 h at room temperature. Work-up involves merely filtration of the reagent followed by purification of the crude product.
- Agarwal, Aditi,Vankar, Yashwant D.
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p. 1661 - 1667
(2007/10/03)
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- Polymer-supported ferric chloride as a heterogeneous catalyst for chemoselective deprotection of acetonides
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Acetonides undergo chemoselective deprotection to afford the corresponding 1,2-diols in excellent yields using polymer (PVP)-supported ferric chloride as a heterogeneous catalyst in acetonitrile-dichloromethane at room temperature.
- Chari, M. Adharvana,Syamasundar
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p. 708 - 710
(2007/10/03)
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- Chemoselective deprotection of acid labile primary hydroxyl protecting groups under CBr4-photoirradiation conditions
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The CBr4-photoirradiation in methanol generates a controlled source of HBr, which can chemoselectively deprotect commonly used hydroxyl-protecting groups in saccharides and nucleosides, such as tert-butyldimethylsilyl, isopropylidene, benzylidene and triphenyl ethers in the presence of other acid-labile functional groups. Graphical Abstract.
- Chen, Ming-Yi,Patkar, Laxmikant N.,Lu, Kuo-Cheng,Lee, Adam Shih-Yuan,Lin, Chun-Cheng
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p. 11465 - 11475
(2007/10/03)
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- A one-pot strategy for synthesis of 5-O-(α-D-Arabinofuranosyl)-6-O-(β-D-galactofuranosyl)-D- galactofuranose present in motif E of the Mycobacterium tuberculosis cell wall
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5-O-(α-D-Arabinofuranosyl)-6-O-(β-D-galactofuranosyl)-D- galactofuranose 6 present in motif E of the Macobacterium tuberculosis cell wall has been regio- and stereospecifically synthesized using 3-O-benzoyl-1,2-O-isopropylidine-α-D-galactofuranose (10) as the glycosyl acceptor by the trichloroacetamidate method in a one-pot manner. The diol glycosyl acceptor 10 was smoothly derived from 1,2:5,6-di-O-isopropylidene-α-D-galactofuranose (8) by 3-O-benzoylation and then selective 5,6-O-deacetonation. The preparation of 8 was greatly improved by increasing the ratio of DMF to acetone and using a solid-supported catalyst.
- Wang, Hairong,Ning, Jun
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p. 2521 - 2524
(2007/10/03)
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- A mild and efficient method for chemoselective deprotection of acetonides by bismuth(III) trichloride
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Acetonides undergo chemoselective deprotection to afford the corresponding 1,2-diols in excellent yields using bismuth trichloride in acetonitrile/dichloromethane at ambient temperature.
- Swamy, N.Raghavendra,Venkateswarlu
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p. 7549 - 7552
(2007/10/03)
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- Thio-sugars. IV. Synthesis of carbohydrate 1,3-glycol (six-membered) thionocarbonates and their attempted O-S rearrangement)
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Four six-membered cyclic thionocarbonates (two sec-sec and two prim-sec) were prepared and their radical-promoted O-S rearrangement reaction was examined. The results revealed that the reaction in six-membered rings is difficult compared with the simple r
- Tsuda,Noguchi,Niino
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p. 1210 - 1213
(2007/10/03)
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- The role of the C-3 substituent in the asymmetric dihydroxylation of hexo-5-enofuranosides
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Asymmetric dihydroxylation of vinyl furanosides 1-6 by use of OsO4, AD-mix-α and β is described yielding the corresponding hexofuranose sugars. Vinyl furanosides 2 and 3, with an ester group at C-3, and vinyl manno furanoside 5 on asymmetric dihydroxylation with AD-mix α exhibited high R diastereoselectivity at C-5. Reversal in diastereoselectivity at C-5 was observed for the 3-deoxy vinyl furanoside 6 giving furanosaccharide 6S with the S configuration at C-5.
- Mereyala, Hari Babu,Goud, P. Mallikarjun,Gadikota, Rajendrakumar Reddy,Maddala, Rama Krishna,Reddy, K. Ramasubba
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p. 1201 - 1210
(2007/10/03)
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- Solvolytic behaviors of O-benzoyl, cyclic O,O-thionocarbonate, and O,S- thiolcarbonate groups in 3-O-benzoyl-1,2-O-isopropylidene-α-d-glucofuranose derivatives
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O-Benzoyl, cyclic thionocarbonate, and thiolcarbonate groups in 5,6-O- thiono-, 5,6-O,S-thiol-, and 5,6-S,O-thiolcarbonates of 3-O-benzoyl-1,2-O- isopropylidene-α-D-glucofuranoses behaved differently on solvolysis under alkaline conditions. Generally, the 3-O-benzoyl group was the most vulnerable to NaOH in water or MeOH, while thionocarbonate and thiolcarbonate groups were more reactive than the O-benzoyl group toward methanolysis with NaOMe. In particular, methanolysis of the 5,6-S,O- thiolcarbonate with NaOMe gave a thiirane derivative very rapidly.
- Tsuda, Yoshisuke,Shibayama, Kenji
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p. 1476 - 1479
(2007/10/03)
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- DIPHENYLMETHYLATION OF CARBOHYDRATE HYDROXYL GROUPS BY THE REACTION WITH DIAZO(DIPHENYL)METHANE
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Diphenylmetylation of carbohydrate hydroxyl groups may be effected by the thermal reaction with diazo(diphenyl)methane in absence of catalysts.Migration of the labile ester groups of methyl 2,3,4-tri-O-acetyl-α-D-glucopyranoside and 3-O-benzoyl-1,2-O-isopropylidene-α-D-glucofuranose does not occur during diphenylmethylation by this procedure.The diphenylmethyl group may be readily removed by catalytic hydrogenolysis, and is sufficiently acid-stable to enable the selective hydrolysis of acetal groups.Its use as an O-4 protecting-group and as a non-participating O-2 protecting-group in α-glucoside synthesis has been demonstrated in syntheses of methyl 2,3,6-tri-O-methyl-α-D-glucopyranoside and kojibiose octa-acetate, respectively.
- Jackson, Graham,Jones, Haydn F.,Petursson, Sigthor,Webber, John M.
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p. 147 - 158
(2007/10/02)
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- A Simple Regioselective Partial Hydrolysis of Di-O-isopropylidene Monosaccharides with Copper(II) Ion
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Copper(II) ion was found to be effective for regioselective removal of the 5,6-O-isopropylidene group of α-D-mannose and α-D-glucose derivatives in alcohols at ambient temperature.
- Iwata, Masaaki,Ohrui, Hiroshi
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p. 2837 - 2838
(2007/10/02)
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