The Experts below are selected from a list of 4428 Experts worldwide ranked by ideXlab platform
Kaoru Nakamura - One of the best experts on this subject based on the ideXlab platform.
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Chiral synthesis of secondary alcohols using Geotrichum candidum.
Chirality, 2002Co-Authors: Kaoru Nakamura, Tomoko Matsuda, Tadao HaradaAbstract:Chiral synthesis of secondary alcohols of both the (S)- and (R)-enantiomer with extremely high enantioselectivities (up to >99% ee) using a biocatalyst, Geotrichum candidum, is reviewed. Resting cell and dried-cell preparation using acetone were applied to oxidation, reduction, and deracemization reactions. Many methods to improve the reactivity and enantioselectivity of the reactions were developed. For example, additives such as secondary alcohols and hydrophobic resin (Amberlite XAD) were used in nonaqueous reaction media such as organic and supercritical solvents as well as in aqueous ones. As a result, optically pure alcohols of both enantiomers were synthesized on a gram scale.
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Asymmetric reduction of simple aliphatic ketones with dried cells of Geotrichum candidum
Tetrahedron-asymmetry, 2002Co-Authors: Tomoko Matsuda, Yuta Nakajima, Tadao Harada, Kaoru NakamuraAbstract:Simple aliphatic ketones such as 2-pentanone, 2-butanone, 3-hexanone, etc., were reduced with high yield and excellent enantioselectivity to the corresponding (S)-alcohols using dried cells of Geotrichum candidum.
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Chiral synthesis of secondary alcohols using Geotrichum candidum
Chirality, 2002Co-Authors: Kaoru Nakamura, Tomoko Matsuda, Tadao HaradaAbstract:Chiral synthesis of secondary alcohols of both the (S)- and (R)-enantiomer with extremely high enantioselectivities (up to >99% ee) using a biocatalyst, Geotrichum candidum, is reviewed. Resting cell and dried-cell preparation using acetone were applied to oxidation, reduction, and deracemization reactions. Many methods to improve the reactivity and enantioselectivity of the reactions were developed. For example, additives such as secondary alcohols and hydrophobic resin (Amberlite™ XAD) were used in nonaqueous reaction media such as organic and supercritical solvents as well as in aqueous ones. As a result, optically pure alcohols of both enantiomers were synthesized on a gram scale. Chirality 14:703–708, 2002. © 2002 Wiley-Liss, Inc.
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asymmetric synthesis of r 2 chloro 1 m chlorophenyl ethanol using acetone powder of Geotrichum candidum
Biotechnology Letters, 2001Co-Authors: Hiroki Hamada, Tomoko Matsuda, Tadao Harada, Takashi Miura, Hidenori Kumobayashi, Kaoru NakamuraAbstract:The asymmetric synthesis of (R)-2-chloro-1-(m-chlorophenyl)ethanol, a precursor for a key intermediate of an important class of drugs, was achieved by reduction of the corresponding ketone using an acetone powder of Geotrichum candidum with 98% ee and 94% yield based on the starting amount of ketone.
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enantioselective oxidation and reduction by Geotrichum candidum
Journal of Synthetic Organic Chemistry Japan, 2001Co-Authors: Tomoko Matsuda, Tadao Harada, Kaoru NakamuraAbstract:Biocatalyst has been attracted increasing attention for asymmetric synthesis due to the high enantioselectivities and environmentally friendliness. We have been developing methods using a fungus, Geotrichum candidum, which has many enzymes catalyzing the enantioselective oxidation and reduction reactions of non-natural substrates. These enzymes in the resting or dried cells were used in an organic solvent, supercritical carbon dioxide, or aqueous media for oxidation, reduction or deracemization reactions. The usefulness of these methods was also demonstrated in the preparation, on a multi-gram scale, of optically pure alcohols.The effect of fluorine substituents on the enantioselectivity of the reduction using the dried cell was also investigated thoroughly, and it was found that the reduction of trifluoromethyl ketones affords (S) -trifluoromethyl carbinols in excellent ee, whereas the reduction of methyl ketones gives the corresponding alcohols of the opposite configuration in excellent ee. The enzymes in the cells were separated to investigate the origin of different enantioselectivities between the methyl and trifluoromethyl ketones.
Tadao Harada - One of the best experts on this subject based on the ideXlab platform.
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Chiral synthesis of secondary alcohols using Geotrichum candidum.
Chirality, 2002Co-Authors: Kaoru Nakamura, Tomoko Matsuda, Tadao HaradaAbstract:Chiral synthesis of secondary alcohols of both the (S)- and (R)-enantiomer with extremely high enantioselectivities (up to >99% ee) using a biocatalyst, Geotrichum candidum, is reviewed. Resting cell and dried-cell preparation using acetone were applied to oxidation, reduction, and deracemization reactions. Many methods to improve the reactivity and enantioselectivity of the reactions were developed. For example, additives such as secondary alcohols and hydrophobic resin (Amberlite XAD) were used in nonaqueous reaction media such as organic and supercritical solvents as well as in aqueous ones. As a result, optically pure alcohols of both enantiomers were synthesized on a gram scale.
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Asymmetric reduction of simple aliphatic ketones with dried cells of Geotrichum candidum
Tetrahedron-asymmetry, 2002Co-Authors: Tomoko Matsuda, Yuta Nakajima, Tadao Harada, Kaoru NakamuraAbstract:Simple aliphatic ketones such as 2-pentanone, 2-butanone, 3-hexanone, etc., were reduced with high yield and excellent enantioselectivity to the corresponding (S)-alcohols using dried cells of Geotrichum candidum.
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Chiral synthesis of secondary alcohols using Geotrichum candidum
Chirality, 2002Co-Authors: Kaoru Nakamura, Tomoko Matsuda, Tadao HaradaAbstract:Chiral synthesis of secondary alcohols of both the (S)- and (R)-enantiomer with extremely high enantioselectivities (up to >99% ee) using a biocatalyst, Geotrichum candidum, is reviewed. Resting cell and dried-cell preparation using acetone were applied to oxidation, reduction, and deracemization reactions. Many methods to improve the reactivity and enantioselectivity of the reactions were developed. For example, additives such as secondary alcohols and hydrophobic resin (Amberlite™ XAD) were used in nonaqueous reaction media such as organic and supercritical solvents as well as in aqueous ones. As a result, optically pure alcohols of both enantiomers were synthesized on a gram scale. Chirality 14:703–708, 2002. © 2002 Wiley-Liss, Inc.
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asymmetric synthesis of r 2 chloro 1 m chlorophenyl ethanol using acetone powder of Geotrichum candidum
Biotechnology Letters, 2001Co-Authors: Hiroki Hamada, Tomoko Matsuda, Tadao Harada, Takashi Miura, Hidenori Kumobayashi, Kaoru NakamuraAbstract:The asymmetric synthesis of (R)-2-chloro-1-(m-chlorophenyl)ethanol, a precursor for a key intermediate of an important class of drugs, was achieved by reduction of the corresponding ketone using an acetone powder of Geotrichum candidum with 98% ee and 94% yield based on the starting amount of ketone.
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enantioselective oxidation and reduction by Geotrichum candidum
Journal of Synthetic Organic Chemistry Japan, 2001Co-Authors: Tomoko Matsuda, Tadao Harada, Kaoru NakamuraAbstract:Biocatalyst has been attracted increasing attention for asymmetric synthesis due to the high enantioselectivities and environmentally friendliness. We have been developing methods using a fungus, Geotrichum candidum, which has many enzymes catalyzing the enantioselective oxidation and reduction reactions of non-natural substrates. These enzymes in the resting or dried cells were used in an organic solvent, supercritical carbon dioxide, or aqueous media for oxidation, reduction or deracemization reactions. The usefulness of these methods was also demonstrated in the preparation, on a multi-gram scale, of optically pure alcohols.The effect of fluorine substituents on the enantioselectivity of the reduction using the dried cell was also investigated thoroughly, and it was found that the reduction of trifluoromethyl ketones affords (S) -trifluoromethyl carbinols in excellent ee, whereas the reduction of methyl ketones gives the corresponding alcohols of the opposite configuration in excellent ee. The enzymes in the cells were separated to investigate the origin of different enantioselectivities between the methyl and trifluoromethyl ketones.
Tomoko Matsuda - One of the best experts on this subject based on the ideXlab platform.
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Oxidation of aromatic and aliphatic aldehydes to carboxylic acids by Geotrichum candidum aldehyde dehydrogenase
Tetrahedron, 2020Co-Authors: Tomoyasu Hoshino, Emi Yamabe, Muhammad Arisyi Hawari, Mayumi Tamura, Shuji Kanamaru, Keisuke Yoshida, Afifa Ayu Koesoema, Tomoko MatsudaAbstract:Abstract Oxidation reaction is one of the most important and indispensable organic reactions, so that green and sustainable catalysts for oxidation are necessary to be developed. Herein, biocatalytic oxidation of aldehydes was investigated, resulted in the synthesis of both aromatic and aliphatic carboxylic acids using a Geotrichum candidum aldehyde dehydrogenase (GcALDH). Moreover, selective oxidation of dialdehydes to aldehydic acids by GcALDH was also successful.
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Utility of ionic liquid for Geotrichum candidum-catalyzed synthesis of optically active alcohols
Journal of Molecular Catalysis B-enzymatic, 2008Co-Authors: Takamasa Tanaka, Noritaka Iwai, Tomoko Matsuda, Tomoya KitazumeAbstract:Abstract Ionic liquids have recognized as a solvent for Geotrichum candidum -catalyzed optical resolution and/or deracemization of racemic secondary alcohols, giving optically active alcohols. The immobilized Geotrichum candidum proceeded the enantioselective oxidation of alcohols, producing chiral alcohols in an ionic liquid. Further, deracemization of racemic alcohols was proceeded to give the corresponding chiral alcohols in high yield with excellent stereoselectivity by the Geotrichum candidum –NaBH 4 system in the mixture of MES buffer solution and ionic liquid.
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An effective method to use ionic liquids as reaction media for asymmetric reduction by Geotrichum candidum
Tetrahedron Letters, 2006Co-Authors: Tomoko Matsuda, Noritaka Iwai, Yusuke Yamagishi, Shinichi Koguchi, Tomoya KitazumeAbstract:An effective method was developed to use an enzyme in ionic liquids; the asymmetric reduction of ketones by Geotrichum candidum in ionic liquids proceeded smoothly with excellent enantioselectivity when the cell was immobilized on water-absorbing polymer containing water, while the reaction without the polymer did not proceed.
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Chiral synthesis of secondary alcohols using Geotrichum candidum.
Chirality, 2002Co-Authors: Kaoru Nakamura, Tomoko Matsuda, Tadao HaradaAbstract:Chiral synthesis of secondary alcohols of both the (S)- and (R)-enantiomer with extremely high enantioselectivities (up to >99% ee) using a biocatalyst, Geotrichum candidum, is reviewed. Resting cell and dried-cell preparation using acetone were applied to oxidation, reduction, and deracemization reactions. Many methods to improve the reactivity and enantioselectivity of the reactions were developed. For example, additives such as secondary alcohols and hydrophobic resin (Amberlite XAD) were used in nonaqueous reaction media such as organic and supercritical solvents as well as in aqueous ones. As a result, optically pure alcohols of both enantiomers were synthesized on a gram scale.
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Asymmetric reduction of simple aliphatic ketones with dried cells of Geotrichum candidum
Tetrahedron-asymmetry, 2002Co-Authors: Tomoko Matsuda, Yuta Nakajima, Tadao Harada, Kaoru NakamuraAbstract:Simple aliphatic ketones such as 2-pentanone, 2-butanone, 3-hexanone, etc., were reduced with high yield and excellent enantioselectivity to the corresponding (S)-alcohols using dried cells of Geotrichum candidum.
Paulo J. S. Moran - One of the best experts on this subject based on the ideXlab platform.
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Bioreduction of 2-azido-1-arylethanones mediated by Geotrichum candidum and Rhodotorula glutinis
Journal of Molecular Catalysis B-enzymatic, 2006Co-Authors: Lucidio Cristovão Fardelone, J. Augusto R. Rodrigues, Paulo J. S. MoranAbstract:Abstract Enantioselective reductions of p -X-C 6 H 4 C( O)CH 2 N 3 (X = H, Cl, Br, CH 3 , OCH 3 ) mediated by Rhodotorula glutinis and Geotrichum candidum afforded the corresponding alcohols with complementary R and S configurations, respectively, in excellent yield and enantiomeric excesses. The obtained ( R )-azidoalcohols are important starting materials for preparation of natural products and valuable pharmaceutical compounds such as ( R )-Tembamide and ( R )-Aegeline.
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Bioreduction of α-haloacetophenones by Rhodotorula glutinis and Geotrichum candidum
Arkivoc, 2003Co-Authors: Lucidio Cristovão Fardelone, J. Augusto R. Rodrigues, Paulo J. S. MoranAbstract:Enantioselective reductions with enantiocomplementarity of α-haloacetophenones by Rhodotorula glutinis CCT 2182 and Geotrichum candidum CCT 1205 afforded the corresponding (R)and (S)-halohydrins (halo = Cl, Br and I), respectively, in high chemical yields (89-99%) and enantiomeric excesses (92-99%). These halohydrins are potential chiral building blocks for the stereoselective syntheses of valuable compounds.
Juliana A. Vale - One of the best experts on this subject based on the ideXlab platform.
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Biocatalytic production of Ɛ-caprolactone using Geotrichum candidum cells immobilized on functionalized silica.
Applied microbiology and biotechnology, 2020Co-Authors: André Leonardo P. Silva, Taiza Nayara Da Silva Caridade, Renata Rodrigues Magalhães, Kelly Teotonio De Sousa, Christian Carlos De Sousa, Juliana A. ValeAbstract:Immobilization of the Geotrichum candidum (CCT 1205) cell with functionalized silica creates promising biocatalysts for production of ɛ-caprolactone. The results obtained by immobilization of the whole cell on SiO2-NH2 and SiO2-SH supports indicate that the presence of reactive functional groups on the support may promote effective chemical bonds with the cell walls resulting the decreased dehydrogenases enzyme activity (5% yield in less than 2h) and consequently, increased Baeyer-Villiger monooxygenases enzyme activity with redacting of 25% of time reaction when is used SiO2-NH2 as support and 50% through use of SiO2-SH as support relative to free cells when cyclohexanone is used as a substrate. The catalysts SiO2–NH2–Geotrichum candidum and SiO2–SH–Geotrichum candidum were recycling and reused in the ɛ-caprolactone synthesis from cyclohexanone, and the biocatalysts promoted a quantitative conversion up to the eighth reaction cycle. • Immobilized microorganism is more efficient than free cell in the caprolactone synthesis. • The reaction times for amino and thiol groups in support were 3 h and 2 h, respectively. • These catalysts showed higher ɛ-caprolactone conversion at higher concentrations.
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Biocatalytic production of Ɛ-caprolactone using Geotrichum candidum cells immobilized on functionalized silica
Applied Microbiology and Biotechnology, 2020Co-Authors: André Leonardo Patrício Silva, Taiza Nayara Da Silva Caridade, Renata Rodrigues Magalhães, Kelly Teotonio De Sousa, Christian Carlos De Sousa, Juliana A. ValeAbstract:Immobilization of the Geotrichum candidum (CCT 1205) cell with functionalized silica creates promising biocatalysts for production of ɛ-caprolactone. The results obtained by immobilization of the whole cell on SiO_2-NH_2 and SiO_2-SH supports indicate that the presence of reactive functional groups on the support may promote effective chemical bonds with the cell walls resulting the decreased dehydrogenases enzyme activity (5% yield in less than 2h) and consequently, increased Baeyer-Villiger monooxygenases enzyme activity with redacting of 25% of time reaction when is used SiO_2-NH_2 as support and 50% through use of SiO_2-SH as support relative to free cells when cyclohexanone is used as a substrate. The catalysts SiO_2–NH_2 –Geotrichum candidum and SiO_2–SH –Geotrichum candidum were recycling and reused in the ɛ-caprolactone synthesis from cyclohexanone, and the biocatalysts promoted a quantitative conversion up to the eighth reaction cycle. Key points • Immobilized microorganism is more efficient than free cell in the caprolactone synthesis. • The reaction times for amino and thiol groups in support were 3 h and 2 h, respectively. • These catalysts showed higher ɛ-caprolactone conversion at higher concentrations.