- Identification of glutathione and related cysteine conjugates derived from reactive metabolites of methyleugenol in rats
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Methyleugenol (ME), an alkenylbenzene compound, is a constituent of many foods and is used as flavoring agent in foodstuffs and as fragrance in cosmetics. It has been reported that exposure to ME can cause carcinogenicity, cytotoxicity, and genotoxicity.
- Yao, Huina,Peng, Ying,Zheng, Jiang
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- Chemical Interaction of Protein Cysteine Residues with Reactive Metabolites of Methyleugenol
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Methyleugenol (ME), an alkenylbenzene compound, is a natural ingredient of several herbs and is used as flavoring agent in foodstuffs and fragrance in cosmetics. The hepatotoxicity, cytotoxicity, and carcinogenesis of ME have been well documented, and met
- Feng, Yukun,Wang, Hui,Wang, Qian,Huang, Wenlin,Peng, Ying,Zheng, Jiang
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- A convenient synthesis of 1-aryl-2-propanone precursors of α-methyldopa
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A simple two-step approach to 1-(3,4-dimethoxyphenyl)- and 1-[3,4-(methylenedioxy)phenyl]-2-propanone (4a and 4b), useful intermediates for α-methyldopa, is described. It is based on the epoxidation of the widely available methyleugenol (1-allyl-3,4-dimethoxybenzene, 1a) and safrole [1-allyl-3,4-(methylenedioxy)benzene, 1b] with hydrogen peroxide catalyzed by tungsten peroxo complex 2a under two-phase conditions, followed by isomerization of the intermediate epoxides 3a and 3b by lithium iodide.
- An,D'Aloisio,Venturello
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- Diphenyl[b,d] oxacycloheptane compound as well as preparation and application thereof
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The invention belongs to the technical field of organic synthesis and relates to a method for synthesizing a diphenyl[b,d] oxacycloheptane compound from a lignin model compound. The compound has a structural formula as shown in the specification, in the formula, R1, R2, R3 and R4=-H or -OCH3, and R5=-CH2CH2CH3, -CH2CH2COOCH3, -CH2CH2COOH, -CH2CH2CH2OH, -CH3 or -CHO. According to the method provided by the invention, a lignin beta-O-4 dimer model compound is adopted as a raw material to prepare the diphenyl[b,d] oxacycloheptane compound through oxidative coupling reactions. The prepared diphenyl[b,d] oxacycloheptane compound has anti-tumor cell activity and activity for inhibiting rate hepatocorpuscular cytochrome P450. The invention discloses the method for synthesizing the diphenyl[b,d] oxacycloheptane compound from the lignin beta-O-4 dimer model compound as a raw material for a first time, and the method is simple to operate, gentle in reaction condition, good in environment protection, simple in aftertreatment, high in yield and good in industrial production prospect.
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- Prilezhaev dihydroxylation of olefins in a continuous flow process
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Epoxidation of both terminal and non-terminal olefins with peroxy acids is a well-established and powerful tool in a wide variety of chemical processes. In an additional step, the epoxide can be readily converted into the corresponding trans-diol. Batch-wise scale-up, however, is often troublesome because of the thermal instability and explosive character of the peroxy acids involved. This article describes the design and semi-automated optimization of a continuous flow process and subsequent scale-up to preparative production volumes in an intrinsically safe manner. Olefins go with the flow: Prilezhaev dihydroxylation can be performed on a large scale in continuous flow microreactor systems in the oxidation of terminal and internal olefins. Major drivers for a continuous flow process include better control, improved safety, and a faster overall process, leading to a significantly higher throughput. Copyright
- Van Den Broek, Bas A. M. W.,Becker, René,K?ssl, Florian,Delville, Mari?lle M. E.,Nieuwland, Pieter J.,Koch, Kaspar,Rutjes, Floris P. J. T.
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experimental part
p. 289 - 292
(2012/06/01)
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- Epoxidation of olefins by β-bromoalkoxydimethylsulfonium ylides
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Olefins can be converted to their respective epoxides in a one-pot procedure by dissolving the olefin in anhydrous DMSO, adding NBS to the reaction mixture to generate a β-bromoalkoxydimethylsulfonium ylide, and then adding DBU to the reaction mixture. A large variety of alkenes were successfully epoxi-dized with yields largely dependent on the structure of the alkene. Most importantly, the facial selectivity of this one-pot process is the opposite of that observed when using traditional epoxidizing reagents. Electron-poor alkenes are not epoxidized under these conditions.
- Majetich, George,Shimkus, Joel,Li, Yang
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supporting information; experimental part
p. 6830 - 6834
(2011/03/18)
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- Ring-opening reactions of epoxides catalyzed by molybdenum(VI) dichloride dioxide
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Transformation of epoxides to β-alkoxy alcohols, acetonides, and α-alkoxy ketones is achieved by using molybdenum(VI) dichloride dioxide (MoO2Cl2) as a catalyst. Alcohol, aldehyde, oxime, tosyl, and tert-butyldimethylsilyl functional groups are tolerated during the methanolysis and acetonidation of the functionalized epoxides. No polymerization product is observed with any of the epoxides. Direct conversion of epoxides devoid of sensitive functional groups into the corresponding α-methoxy ketone is achieved in a single step by using the MoO2Cl 2/Oxone system. Georg Thieme Verlag Stuttgart.
- Jeyakumar, Kandasamy,Chand, Dillip Kumar
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p. 807 - 819
(2008/09/21)
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- Regioselectivity and diasteroselectivity in Pt(II)-mediated "green" catalytic epoxidation of terminal alkenes with hydrogen peroxide: Mechanistic insight into a peculiar substrate selectivity
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Recently developed electron-poor Pt(II) catalyst 1 with the "green" oxidant 35% hydrogen peroxide displays high activity and complete substrate selectivity in the epoxidation of terminal alkenes because of stringent steric and electronic requirements. In the presence of isolated dienes bearing terminal and internal double bonds, epoxidation is completely regioselective toward the production of terminal epoxides. Insight into the mechanism is gained by means of a reaction progress kinetic analysis approach that underlines the peculiar role of 1 in activating both the alkene and H 2O2 in the rate-determining step providing a rare example of nucleophilic oxidation of alkenes by H2O2.
- Colladon, Marco,Scarso, Alessandro,Sgarbossa, Paolo,Michelin, Rino A.,Strukul, Giorgio
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p. 7680 - 7689
(2008/02/05)
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- High hypolipidemic activity of saturated side-chain α-asarone analogs
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With the aim of evaluating the pharmacophore potential of the side chain of α-asarone (1) regarding its high hypolipidemic activity, the series of derivatives 7a-7e, and 11-13 were evaluated pharmacologically. For the hydrocarbon compounds 7a-7e, with a variable-size side chain, significant decreases in serum cholesterol, LDL-cholesterol, and triglyceride levels and significant increases in HDL-cholesterol levels were observed in mice. The small-size side-chain derivatives were even more active than 1 in reducing cholesterol. The results suggested that the length and saturated character of the side chain seem to be a key feature in improving hypolipidemic activity of α-asarone (1) analogs.
- Cruz, Adriana,Garduno, Leticia,Salazar, Maria,Martinez, Elizdath,Diaz, Francisco,Chamorro, German,Tamariz, Joaquin
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p. 587 - 595
(2007/10/03)
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