- Current perspectives on microwave-enhanced reactions of monosaccharides promoted by heterogeneous catalysts
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Involvement of heterogeneous catalysts as promoters of carbohydrate conversions, in synergy with microwaves as the heating source, is reported. This paper deals with the application of ion-exchange resins, zeolites, clays and metal oxides as convenient mediators for key transformations of carbohydrates. A special emphasis is placed on the use of (doped) mineral supports, in solventless conditions, as clean promoters in combination with microwave dielectric heating.
- Richel, Aurore,Laurent, Pascal,Wathelet, Bernard,Wathelet, Jean-Paul,Paquot, Michel
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scheme or table
p. 141 - 147
(2012/02/04)
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- Design and synthesis by click triazole formation of paclitaxel mimics with simplified core and side-chain structures
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A library of paclitaxel (taxol) mimics was obtained by a straightforward strategy involving rational design and an efficient synthesis of a simplified taxane core substitute, together with a click-chemistry combinatorial search for phenylisoserine side-chain surrogates.
- Manach, Claire Le,Baron, Aurélie,Guillot, Régis,Vauzeilles, Boris,Beau, Jean-Marie
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scheme or table
p. 1462 - 1465
(2011/06/10)
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- Three new flavonoid glycosides, byzantionoside B 6′-O-sulfate and xyloglucoside of (Z)-hex-3-en-1-ol from Ruellia patula
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Three new flavonoid glycosides, demethoxycentaureidin 7-O- β-D-galacturonopyranoside, pectolinarigenin 7-O- α-L-rhamnopyranosyl- (1?→4″)- β-D-glucopyranoside and 7-O- α-L-rhamnopyranosyl-(1?→4″)- β-D- glucuronopyranoside, a new megastigmane glucoside, byzantionoside B 6′-O-sulfate, and a new (Z)-hex-3-en-1-ol O-β-D-xylopyranosyl- (1″→2′)- β-D-glucopyranoside, were isolated from leaves of Ruellia patula JACQ., together with 12 known compounds, β-sitosterol glucoside, vanilloside, bioside (decaffeoyl verbascoside), acteoside (verbascoside), syringin, benzyl alcohol O- β-D-xylopyranosyl- (1″→2′)- β-D-glucopyranoside, cistanoside E, roseoside, phenethyl alcohol O- β-D-xylopyranosyl-(1″→2′)- β-D-glucopyranoside, (+)-lyoniresinol 3 α-O- β-D- glucopyranoside, isoacteoside and 3,4,5-trimethoxyphenol O- α-L- rhamnopyranosyl-(1″→6′)- β-D-glucopyranoside. Their structures were elucidated by means of spectroscopic analyses.
- Samy, Mamdouh Nabil,Khalil, Hany Ezzat,Sugimoto, Sachiko,Matsunami, Katsuyoshi,Otsuka, Hideaki,Kamel, Mohamed Salah
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experimental part
p. 725 - 729
(2011/07/30)
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- Degradation kinetics of glucuronic acid in subcritical water
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The degradation kinetics of glucuronic acid (GlcA) under subcritical conditions from 160 to 200 °C was studied in a continuous tubular reactor. The formation of glucuronolactone (GlcL) during the treatment of GlcA in subcritical water was substantiated by ESITOF-MS and 1H NMR. The degradation of GlcA consisted of the reversible conversion of GlcA to GlcL and the irreversible degradation of the two compounds. The changes in the concentrations of GlcA and GlcL with residence time could be described by first-order kinetics. Higher temperatures accelerated the degradation of GlcA, and thus resulted in rises in the pH value. The degradation reaction of GlcL under the same conditions was also investigated. The activation energy of the reverse hydrolysis of GlcA to GlcL and that of the hydrolysis of GlcL to GlcA were determined to be 88.5 and 63.2 kJ/mol respectively. The enthalpy change in the reversible conversion between GlcA and GlcL was 25.4 kJ/mol.
- Wang, Rongchun,Neoh, Tze Loon,Kobayashi, Takashi,Miyake, Yasuhito,Hosoda, Asao,Taniguchi, Hisaji,Adachi, Shuji
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experimental part
p. 601 - 605
(2011/04/23)
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- Large scale synthesis of the acetonides of l-glucuronolactone and of l-glucose: easy access to l-sugar chirons
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1,2-O-Isopropylidene-α-l-glucurono-3,6-lactone may be synthesized on a 100-200 g scale from cheaply available d-glucoheptonolactone in an overall yield of 94% in four steps via l-glucuronolactone. Subsequent elaboration to l-glucose, diacetone-l-glucose (1,2:5,6-di-O-isopropylidene-α-l-glucofuranose), and monoacetone-l-glucose (1,2-O-isopropylidene-α-l-glucofuranose) allows easy access to a range of l-sugar chirons.
- Weymouth-Wilson, Alexander C.,Clarkson, Robert A.,Jones, Nigel A.,Best, Daniel,Wilson, Francis X.,Pino-González, Maria-Soledad,Fleet, George W.J.
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experimental part
p. 6307 - 6310
(2010/01/18)
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- Process for selectively oxidizing primary hydroxyl groups of organic compounds, and resin containing adsorbed catalyst for use therein
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A method for selectively oxidizing the primary hydroxyl group of an organic compound which comprises reacting a resin having an amine oxide adsorbed thereon and an electrolytically oxidized product of a halogen-containing compound with the organic compound having the primary hydroxyl group.
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- Radical-based asymmetric synthesis: an iterative approach to 1, 3, 5, ... (2n + 1) polyols.
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[formula: see text] A conceptually novel approach to 1, 3, 5, ... (2n + 1) polyols based on iterative stereo-controlled homologation of chiral hydroxyalkyl radicals is reported. Starting from alpha-keto ester precursors, the general sequence of (1) ketone
- Garner,Anderson
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p. 1057 - 1059
(2008/02/09)
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