- Xylochemical synthesis and biological evaluation of shancigusin c and bletistrin g
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The biological activities of shancigusin C (1) and bletistrin G (2), natural products isolated from orchids, are reported along with their first total syntheses. The total synthesis of shancigusin C (1) was conducted by employing the Perkin reaction to forge the central stilbene core, whereas the synthesis of bletistrin G (2) was achieved by the Wittig olefination followed by several regiose-lective aromatic substitution reactions. Both syntheses were completed by applying only renewable starting materials according to the principles of xylochemistry. The cytotoxic properties of shancigusin C (1) and bletistrin G (2) against tumor cells suggest suitability as a starting point for further structural variation.
- Efferth, Thomas,Geske, Leander,Kauhl, Ulrich,Opatz, Till,Saeed, Mohamed E. M.,Schüffler, Anja,Thines, Eckhard
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supporting information
(2021/06/16)
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- Method for preparing silicon compounds
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The invention provides a method for preparing silicon compounds, and belongs to the field of chemical synthesis. The method for preparing the silicon compounds comprises the following processes that citric acid is used as a raw material for performing oxidative decarboxylation to obtain a compound 1,3-acetone dicarboxylic acid; esterification reaction is carried out to obtain a compound 1,3-acetone dicarboxylic acid dimethyl ester; catalytic hydrogenation reduction is carried out to obtain a compound 3-hydroxyglutaric acid dimethyl ester; etherification reaction is carried out to obtain a compound3-tertiary butyl dimethyl siloxy dimethyl glutarate; saponification, dehydration and purification are carried out to obtain 3-tert-butyl-dimethylsiloxyglutaric anhydride; and a catalyst for catalytic hydrogenation is Cu/ZnO/Al2O3 prepared by a precipitation reduction method. According to the method for preparing the silicon compounds, the catalyst for catalytic hydrogenation is optimized, so that in the hydrogenation reduction reaction, the hydrogenation activity of a Cu catalyst is significantly improved, the selectivity is increased, and the generation of by-products is reduced; and theproduct yield and purity are significantly improved by recrystallization with a mixed solvent.
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Paragraph 0079; 0086; 0087; 0088; 0088; 0089
(2019/11/14)
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- Catalytic hydrogenation of persubstituted p-nitrosophenols
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Catalytic hydrogenation of dialkyl 2-hydroxy-4,6-dimethyl-5-nitrosobenzene- 1,3-dicarboxylates over Pd/C gave the corresponding previously unknown dialkyl 5-amino-2-hydroxy-4,6-dimethylbenzene-1,3-dicarboxylates. The first-order rate constants for the hydrogenation process were found to be linearly related to steric constants of the alkyl groups.
- Slashchinin,Tovbis,Root,Zadov,Sokolenko
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experimental part
p. 517 - 519
(2010/08/19)
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- Process for the industrial synthesis of the methyl diester of 5-amino-3-carboxymethyl-4-cyano-2-thiophenecarboxylic acid, and application to the synthesis of bivalent salts of ranelic acid and their hydrates
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Process for the industrial synthesis of the compound of formula (I): Application to the synthesis of bivalent salts of ranelic acid and more especially strontium ranelate and its hydrates.
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- PROCESS FOR THE PREPARATION OF DIALKYL 3-OXOGLUTARATES
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This invention relates to a process for the preparation of 3-oxoglutarates of general formula (I), wherein R stands for methyl or ethyl. Said process comprises reacting citric acid of the formula (II) or the monohydrate thereof with chlorosulphonic acid in a lower chlorinated aliphatic hydrocarbon and reacting the intermediate thus obtained with methanol or ethanol by applying a ratio of lower chlorinated aliphatic hydrocarbon to chlorosulphonic acid in the range of 0,1:1 to 1:1 by volume and carrying out the addition of citric acid to the mixture of chlorosulphonic acid and lower aliphatic hydrocarbon at a rate of 1 - 2 kg/minute. The dialkyl 3-oxoglutarates are valuable pharmaceutical intermediates.
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- Large scale synthesis of dimethyl 1,3-acetonedicarboxylate
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Synthesis of dimethyl 1,3-acetonedicarboxylate from citric acid and sulfuric acid is described.
- Kotha, Sambasivarao,Joseph, Arul,Sivakumar, Rallapalli,Manivannan, Ethirajan
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p. 397 - 398
(2007/10/03)
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- Synthesis and spectroscopic study of 13C-labelled citric acids
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The synthesis of (1'-13C)-, (3-13C)- and (2,4-13C2)citric acid from simple starting compounds is described.Using the same procedure, any mono- or multiply-labelled citric acid can be prepared.The 13C-labelled citric acids have been characterized by 1H NMR, 13C NMR and mass spectroscopy.
- Winkel, C.,Buitenhuis, E. G.,Lugtenburg, J.
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- Use of β-Ketocarboxylic Acids for Syntheses of 6-Substituted 4-Hydroxy-2-pyrones and Acyclic β-Diketones
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β-Ketocarboxylic acids including β-ketoglutaric acid half-esters were cyclized by treating them with 1,1'-carbonyl-diimidazole to give 6-substituted 3-acyl-4-hydroxy-2-pyrones in good yields. 5-Aryl-3,5-dioxo-1-pentanoic acid and monomethyl malonate gave 6-aryl-4-hydroxy-2-pyrone and dimethyl β-ketoglutarate, respectively, on similar treatment.Anibin, one of the Aniba alkaloids, was synthesized from 5-(3-pyridyl)-4-hydroxy-2-pyrone.In addition, it was confirmed that reaction of magnesium β-ketocarboxylate with acylimidazolide gave the corresponding acyclic β-diketone in excellent yield.Keywords - β-ketocarboxilic acid; biogenetic-type synthesis; 4-hydroxy-2-pyrone; β-polyketide; β-ketoglutaric acid; dehydroacetic acid; anibin; Aniba alkaloid; 3-acyl-4-hydroxy-2-pyrone; β-diketone.
- Ohta, Shunsaku,Tsujimura, Atsuhiko,Okamoto, Masao
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p. 2762 - 2768
(2007/10/02)
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- A CONVENIENT ONE-POT PROCEDURE FOR SYNTHESIS OF THIOL ESTERS USING MAGNESIUM ION AS A CATALYST
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Various thiol esters (R1COSR2) were prepared in high yields by treatment of 1-acylimidazole with thiols in the presence of a catalytic amount of Mg(OEt)2.Malonic half-thiol esters 1OCOCH(R3)COSR2> were also prepared in good yields by treating magnesium monoalkyl malonate 1OCOCH(R3)COOMg0.5> with carbonyl-1,1'-diimidazole followed by addition of thiols.
- Ohta, Shunsaku,Okamoto, Masao
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p. 3245 - 3246
(2007/10/02)
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