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Robert S Phillips - One of the best experts on this subject based on the ideXlab platform.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
Jay M. Patel - One of the best experts on this subject based on the ideXlab platform.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
Jun Huang - One of the best experts on this subject based on the ideXlab platform.
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palladium doped silica alumina catalysts obtained from double flame fsp for chemoselective hydrogenation of the model Aromatic Ketone acetophenone
Journal of Catalysis, 2013Co-Authors: Zichun Wang, Meng Meng Chen, Suman Pokhrel, Michael Hunger, Lutz Madler, Jun HuangAbstract:Chemoselective hydrogenation of Aromatic Ketones is an important reaction in the production of fine chemicals and pharmaceuticals. A typical example of this class of reactions is the hydrogenation of acetophenone (Aph) over the supported noble metal catalysts. In this research, Pd/silica–alumina (Pd/SA) catalysts have been prepared for Aph hydrogenation with the emerging double-flame spray pyrolysis system (decouples the two pathways of support formation and metal loading). The Pd particles offered identical electronic properties of Pd surface, which contributed the similar chemoselectivity for the hydrogenation of carbonyl groups on all double-flame-derived catalysts. This revealed a striking difference in Pd surface activity between double-flame and other 5%Pd/SA catalysts. While for supported-Pd catalysts synthesized by other methods, a significant ionic effect of support acidity on the surface Pd particles is reported, and this kind of surface electronic change was not observed for double-flame catalysts. The reaction rate of Aph hydrogenation could be strongly enhanced (TOF from 1.3 × 10−2 s−1 to 4.5 × 10−2 s−1) through tuning the density of surface Bronsted acid sites on supports of 5%Pd/SA via various Si/Al ratios. These advantages of double-flame-derived catalysts clearly demonstrate that double-flame spray pyrolysis can efficiently tune nano-catalysts and their bifunctional activities for specific surface reactions.
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in situ modulation excitation ir study on the dominant product of pt catalyzed Aromatic Ketone hydrogenation
Advanced Materials Research, 2013Co-Authors: Meng Meng Chen, Nobutaka Maeda, Alfons Baiker, Jun HuangAbstract:Chemoselective hydrogenation of Aromatic Ketones plays an important role in producing fine chemicals and pharmaceuticals. One of the simplest model reactions is acetophenone (AP) hydrogenation to corresponding alcohol 1-phenylethanol (PE). We studied the role of dominant product 1-phenylethanol (PE) on a Pt/Al2O3 catalyst. In situ attenuated total reflection infrared spectroscopy (ATR-IR) in combination with modulation excitation spectroscopy (MES) and phase sensitive detection (PSD) revealed that PE was more strongly adsorbed on Al2O3 than on Pt. PE was hardly hydrogenated to 1-cyclohexylethanol (CE) on the support. CO from AP decomposition didn’t inhibit PE adsorption on the support. The strong adsorption and accumulation of PE on the support allows active sites on Pt always accessible to AP, achieving efficient Pt-catalyzed catalysis.
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molecular insight into pt catalyzed chemoselective hydrogenation of an Aromatic Ketone by in situ modulation excitation ir spectroscopy
ACS Catalysis, 2012Co-Authors: Meng Meng Chen, Nobutaka Maeda, Alfons Baiker, Jun HuangAbstract:Chemoselective platinum-catalyzed liquid-phase hydrogenation of Aromatic Ketones is an important reaction in the production of fine chemicals and pharmaceuticals. A typical example of this class of reactions is the hydrogenation of acetophenone (AP) over a Pt/Al2O3 catalyst. We investigated the adsorption behavior of the different reaction components and their reaction pathways using in situ attenuated total reflection infrared spectroscopy in combination with modulation excitation spectroscopy and phase sensitive detection. AP adsorbed on both Pt and the alumina support. On Pt, AP adsorbed in the η1 (O) configuration prevailed, whereas on alumina, AP bound to Lewis acid sites was predominant. In the presence of hydrogen, η1 (O) AP adsorbed on Pt was hydrogenated to the main product, 1-phenylethanol (PE), with high selectivity (82.5%). The produced PE was more strongly adsorbed on the alumina support than on Pt, leading to replacement of AP and accumulation of PE on alumina. Co-adsorption experiments of A...
Vladimir V Popik - One of the best experts on this subject based on the ideXlab platform.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
Luis Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
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mutation of thermoanaerobacter ethanolicus secondary alcohol dehydrogenase at trp 110 affects stereoselectivity of Aromatic Ketone reduction
Organic and Biomolecular Chemistry, 2014Co-Authors: Jay M. Patel, Dewey A Sutton, Vladimir V Popik, Musa M Musa, Luis Rodriguez, Robert S PhillipsAbstract:Alcohol dehydrogenases (ADHs) are enzymes that catalyze the reversible reduction of carbonyl compounds to their corresponding alcohols. We have been studying a thermostable, nicotinamide-adenine dinucleotide phosphate (NADP+)-dependent, secondary ADH from Thermoanaerobacter ethanolicus (TeSADH). In the current work, we expanded our library of TeSADH and adopted the site-saturation mutagenesis approach in creating a comprehensive mutant library at W110. We used phenylacetone as a model substrate to study the effectiveness of our library because this substrate showed low enantioselectivity in our previous work when reduced using W110A TeSADH. Five of the newly designed W110 mutants reduced phenylacetone at >99.9% ee, and two of these mutants exhibit an enantiomeric ratio (E-value) of over 100. These five mutants also reduced 1-phenyl-2-butanone and 4-phenyl-2-butanone to their corresponding (S)-configured alcohols in >99.9% ee. These new mutants of TeSADH will likely have synthetic utility for reduction of Aromatic Ketones in the future.
