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Yonghua Yang - One of the best experts on this subject based on the ideXlab platform.
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lewis acid mediated reactions of 1 cyclopropyl 2 arylethanone derivatives with allenic ester Ethyl Acetoacetate and mEthyl acrylate
Journal of Organic Chemistry, 2008Co-Authors: Xiangying Tang, Yonghua YangAbstract:TMSOTf-mediated reactions of 2-aryl-1-(1-phenylcyclopropyl)ethanones 1 with allenic esters afford a novel method for the synthesis of 6-mEthyl-3a,7-diaryl-3,3a-dihydro-2H-benzofuran-4-one derivatives 2 in moderate yields. In addition, we also found that TMSOTf-mediated reactions of 1-cyclopropyl-2-arylethanones with Ethyl Acetoacetate can provide the corresponding 2,3-dihydrobenzofuran-4-ol and dihydrofuro[2,3-h]chromen-2-one in moderate yields via a sequential reaction involving a nucleophilic ring-opening reaction of the cyclopropane by H2O, one intermolecular aldol type reaction and two intramolecular aldol type reactions, a cyclic transesterification, dehydration, and aromatization. Moreover, by using mEthyl acrylate to replace allenic ester, the corresponding 7-aryl-3,5,6,7-tetrahydro-2H-benzofuran-4-one and 5-aryl-3,5,6,7-tetrahydro-2H-benzofuran-4-one can be formed in moderate to high yields in the presence of Bi(OTf)2Cl. Plausible reaction mechanisms have also been provided on the basis of control...
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lewis acid mediated reactions of 1 cyclopropyl 2 arylethanone derivatives with allenic ester Ethyl Acetoacetate and mEthyl acrylate
Journal of Organic Chemistry, 2008Co-Authors: Min Shi, Xiangying Tang, Yonghua YangAbstract:TMSOTf-mediated reactions of 2-aryl-1-(1-phenylcyclopropyl)ethanones 1 with allenic esters afford a novel method for the synthesis of 6-mEthyl-3a,7-diaryl-3,3a-dihydro-2H-benzofuran-4-one derivatives 2 in moderate yields. In addition, we also found that TMSOTf-mediated reactions of 1-cyclopropyl-2-arylethanones with Ethyl Acetoacetate can provide the corresponding 2,3-dihydrobenzofuran-4-ol and dihydrofuro[2,3-h]chromen-2-one in moderate yields via a sequential reaction involving a nucleophilic ring-opening reaction of the cyclopropane by H2O, one intermolecular aldol type reaction and two intramolecular aldol type reactions, a cyclic transesterification, dehydration, and aromatization. Moreover, by using mEthyl acrylate to replace allenic ester, the corresponding 7-aryl-3,5,6,7-tetrahydro-2H-benzofuran-4-one and 5-aryl-3,5,6,7-tetrahydro-2 H-benzofuran-4-one can be formed in moderate to high yields in the presence of Bi(OTf)2Cl. Plausible reaction mechanisms have also been provided on the basis of control experiments.
Xiangying Tang - One of the best experts on this subject based on the ideXlab platform.
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lewis acid mediated reactions of 1 cyclopropyl 2 arylethanone derivatives with allenic ester Ethyl Acetoacetate and mEthyl acrylate
Journal of Organic Chemistry, 2008Co-Authors: Xiangying Tang, Yonghua YangAbstract:TMSOTf-mediated reactions of 2-aryl-1-(1-phenylcyclopropyl)ethanones 1 with allenic esters afford a novel method for the synthesis of 6-mEthyl-3a,7-diaryl-3,3a-dihydro-2H-benzofuran-4-one derivatives 2 in moderate yields. In addition, we also found that TMSOTf-mediated reactions of 1-cyclopropyl-2-arylethanones with Ethyl Acetoacetate can provide the corresponding 2,3-dihydrobenzofuran-4-ol and dihydrofuro[2,3-h]chromen-2-one in moderate yields via a sequential reaction involving a nucleophilic ring-opening reaction of the cyclopropane by H2O, one intermolecular aldol type reaction and two intramolecular aldol type reactions, a cyclic transesterification, dehydration, and aromatization. Moreover, by using mEthyl acrylate to replace allenic ester, the corresponding 7-aryl-3,5,6,7-tetrahydro-2H-benzofuran-4-one and 5-aryl-3,5,6,7-tetrahydro-2H-benzofuran-4-one can be formed in moderate to high yields in the presence of Bi(OTf)2Cl. Plausible reaction mechanisms have also been provided on the basis of control...
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lewis acid mediated reactions of 1 cyclopropyl 2 arylethanone derivatives with allenic ester Ethyl Acetoacetate and mEthyl acrylate
Journal of Organic Chemistry, 2008Co-Authors: Min Shi, Xiangying Tang, Yonghua YangAbstract:TMSOTf-mediated reactions of 2-aryl-1-(1-phenylcyclopropyl)ethanones 1 with allenic esters afford a novel method for the synthesis of 6-mEthyl-3a,7-diaryl-3,3a-dihydro-2H-benzofuran-4-one derivatives 2 in moderate yields. In addition, we also found that TMSOTf-mediated reactions of 1-cyclopropyl-2-arylethanones with Ethyl Acetoacetate can provide the corresponding 2,3-dihydrobenzofuran-4-ol and dihydrofuro[2,3-h]chromen-2-one in moderate yields via a sequential reaction involving a nucleophilic ring-opening reaction of the cyclopropane by H2O, one intermolecular aldol type reaction and two intramolecular aldol type reactions, a cyclic transesterification, dehydration, and aromatization. Moreover, by using mEthyl acrylate to replace allenic ester, the corresponding 7-aryl-3,5,6,7-tetrahydro-2H-benzofuran-4-one and 5-aryl-3,5,6,7-tetrahydro-2 H-benzofuran-4-one can be formed in moderate to high yields in the presence of Bi(OTf)2Cl. Plausible reaction mechanisms have also been provided on the basis of control experiments.
Maurie A. Trewhella - One of the best experts on this subject based on the ideXlab platform.
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the use of organic solvent systems in the yeast mediated reduction of Ethyl Acetoacetate
Bulletin of the Chemical Society of Japan, 1994Co-Authors: Leonard Y Jayasinghe, Andrew J. Smallridge, Devika Kodituwakku, Maurie A. TrewhellaAbstract:The reduction of Ethyl Acetoacetate to Ethyl (S)-3-hydroxybutyrate, mediated by freeze-dried yeast, proceeds in good yield (53—58%) and with high enantioselectivity (>96%ee) in a number of organic solvents; petroleum ether, diEthyl ether, toluene, and carbon tetrachloride. A small amount of water (0.8 ml (g-yeast)−1) is required for the reaction to proceed. The water/yeast/substrate ratio and the solvent polarity have been found to significantly influence the reactivity of the system. The enantiomeric excess was determined by gas chromatography employing a chiral column.
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the yeast mediated reduction of Ethyl Acetoacetate in petroleum ether
Tetrahedron Letters, 1993Co-Authors: Leonard Y Jayasinghe, Andrew J. Smallridge, Maurie A. TrewhellaAbstract:Abstract Ethyl Acetoacetate is smoothly reduced with high selectivity and good yield to (S)-Ethyl 3-hydroxybutyrate using freeze-dried yeast in petroleum ether.
Wenyong Lou - One of the best experts on this subject based on the ideXlab platform.
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use of ionic liquid to significantly improve asymmetric reduction of Ethyl Acetoacetate catalyzed by acetobacter sp cctcc m209061 cells
Industrial & Engineering Chemistry Research, 2013Co-Authors: Xiaoting Wang, Dongmei Yue, Minhua Zong, Wenyong LouAbstract:Biocatalytic reduction of Ethyl Acetoacetate (EAA) to Ethyl (R)-3-hydroxybutyrate [(R)-EHB] with Acetobacter sp. CCTCC M209061 cells was successfully conducted in ionic liquid (IL)-based biphasic systems. Several water-immiscible ILs were used to construct biphasic systems. The best IL investigated was 1-butyl-3-mEthylimidazolium hexafluorophosphate (C4mim·PF6), which also had good biocompatibility. Several influential variables were examined. The optimum parameters were as follows: volume ratio of buffer to C4mim·PF6, 1/2 (v/v); substrate concentration, 55 mmol/L; buffer pH, 5.5; cosubstrate concentration, 80 mmol/L; reaction temperature, 35 °C; and shaking speed, 220 rpm. Under these optimal conditions, the initial reaction rate, the yield, and the product e.e. were 0.39 mmol/(L min), 90.8%, and >99%, respectively, which were much better than results reported previously. This efficient whole-cell biocatalytic process was feasible on a 450-mL preparative scale, and the immobilized cells showed excellent ...
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biocatalytic anti prelog stereoselective reduction of Ethyl Acetoacetate catalyzed by whole cells of acetobacter sp cctcc m209061
Journal of Biotechnology, 2013Co-Authors: Xiaoting Wang, Wenyong Lou, Xiaohong Chen, Minhua ZongAbstract:The biocatalytic anti-Prelog stereoselective reduction of Ethyl Acetoacetate (EAA) to Ethyl (R)-3-hydroxybutyrate {(R)-EHB} was successfully conducted in the aqueous system using immobilized Acetobacter sp. CCTCC M209061 cells. Among various microorganisms tested, Acetobacter sp. CCTCC M209061 gave the best performance and showed great potential for the bioreduction of EAA to (R)-EHB. Acetobacter sp. CCTCC M209061 cells were immobilized on calcium alginate and then coated with chitosan, and the immobilized cells clearly surpassed the free cells in terms of better thermal stability, storability and recyclability. The optimal co-substrate for the reaction was found to be glucose. The optimal substrate concentration, buffer pH, glucose concentration, reaction temperature, biocatalyst concentration and shaking speed were 35.0 mmol/L, 5.5, 80.0 mmol/L, 35 °C, 0.45 g/mL and 200 rpm, respectively. Under the optimized conditions, the initial reaction rate, the yield and the enantiomeric excess (e.e.) of the product were 1.28 μmol/min, 82.6% and above 99.0%, respectively, which were much higher than those reported previously. The efficient whole-cell biocatalytic process was feasible on a 500-mL preparative scale, and the immobilized cells showed excellent operational stability and could be re-used for at least 10 batches. Additionally, the product e.e. constantly remained above 99.0% regardless of re-use cycles of the biocatalyst.
Min Shi - One of the best experts on this subject based on the ideXlab platform.
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lewis acid mediated reactions of 1 cyclopropyl 2 arylethanone derivatives with allenic ester Ethyl Acetoacetate and mEthyl acrylate
Journal of Organic Chemistry, 2008Co-Authors: Min Shi, Xiangying Tang, Yonghua YangAbstract:TMSOTf-mediated reactions of 2-aryl-1-(1-phenylcyclopropyl)ethanones 1 with allenic esters afford a novel method for the synthesis of 6-mEthyl-3a,7-diaryl-3,3a-dihydro-2H-benzofuran-4-one derivatives 2 in moderate yields. In addition, we also found that TMSOTf-mediated reactions of 1-cyclopropyl-2-arylethanones with Ethyl Acetoacetate can provide the corresponding 2,3-dihydrobenzofuran-4-ol and dihydrofuro[2,3-h]chromen-2-one in moderate yields via a sequential reaction involving a nucleophilic ring-opening reaction of the cyclopropane by H2O, one intermolecular aldol type reaction and two intramolecular aldol type reactions, a cyclic transesterification, dehydration, and aromatization. Moreover, by using mEthyl acrylate to replace allenic ester, the corresponding 7-aryl-3,5,6,7-tetrahydro-2H-benzofuran-4-one and 5-aryl-3,5,6,7-tetrahydro-2 H-benzofuran-4-one can be formed in moderate to high yields in the presence of Bi(OTf)2Cl. Plausible reaction mechanisms have also been provided on the basis of control experiments.