Patents by Inventor Tohru Yokozawa
Tohru Yokozawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9079931Abstract: The present invention provides a novel ruthenium complex which has an excellent catalytic activity in terms of reactivity for asymmetric reduction of a carbonyl compound and enantioselectivity, a catalyst using the ruthenium complex, and a method for preparing optically active alcohol compounds using the ruthenium complex. The present invention relates to a ruthenium complex having ruthenacycle structure, a catalyst for asymmetric reduction consisting of the ruthenium complex, and a method for preparing optically active alcohol using the ruthenium complex.Type: GrantFiled: December 14, 2010Date of Patent: July 14, 2015Assignee: Takasago International CorporationInventors: Hideki Nara, Tohru Yokozawa
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Publication number: 20130041151Abstract: The present invention provides a novel ruthenium complex which has an excellent catalytic activity in terms of reactivity for asymmetric reduction of a carbonyl compound and enantioselectivity, a catalyst using the ruthenium complex, and a method for preparing optically active alcohol compounds using the ruthenium complex. The present invention relates to a ruthenium complex having ruthenacycle structure, a catalyst for asymmetric reduction consisting of the ruthenium complex, and a method for preparing optically active alcohol using the ruthenium complex.Type: ApplicationFiled: December 14, 2010Publication date: February 14, 2013Applicant: TAKASAGO INTERNATIONAL CORPORATIONInventors: Hideki Nara, Tohru Yokozawa
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Patent number: 8222433Abstract: An optically active compound represented by the following formula (5): wherein, in the formula (5), R1 and R2 may be the same or different are an alkyl group optionally having a substituent group selected from the group consisting of an alkoxy group and a halogen atom, a cycloalkyl group optionally having a substituent group selected from the group consisting of an alkoxy group and a halogen atom, an aryl group optionally having a substituent group selected from the group consisting of an alkyl group, an alkoxy group and a halogen atom, an alkoxy group optionally having a substituent group selected from the group consisting of a halogen atom and an aryl group or an aryloxy group optionally having a substituent group selected from the group consisting of an alkyl group, an alkoxy group and a halogen atom; a1 and a2 independently are 0 or 1; and * is axial asymmetry.Type: GrantFiled: March 7, 2011Date of Patent: July 17, 2012Assignees: National University Corporation Tokyo University of Agriculture and Technology, Takasago International CorporationInventors: Ken Tanaka, Tohru Yokozawa, Tomohiko Hakamata
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Patent number: 8188307Abstract: Disclosed is an industrially advantageous production method of optically active ?-amino acid of formula (5a), which includes subjecting an enaminoester of formula (4a) to an asymmetric hydrogenation: wherein * shows an asymmetric carbon atom.Type: GrantFiled: August 31, 2009Date of Patent: May 29, 2012Assignee: Takasago International CorporationInventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
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Patent number: 8076503Abstract: The present invention is a process for producing optically active aminophosphinylbutanoic acids represented by the formula (2), comprising asymmetrically hydrogenating a compound represented by the formula (1) in the presence of a ruthenium-optically active phosphine complex, a process for the production thereof, and a compound useful in a herbicide such as L-AHPB that can be produced with good efficiency and high asymmetric yield.Type: GrantFiled: September 3, 2007Date of Patent: December 13, 2011Assignees: Meiji Seika Pharma Co., Ltd., Takasago International CorporationInventors: Nobuto Minowa, Nozomu Nakanishi, Masaaki Mitomi, Hideki Nara, Tohru Yokozawa
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Publication number: 20110218345Abstract: [Problem to be Solved] To provide an axially asymmetric optically active biarylphosphorus compound that can easily produced without the step of optical resolution which was almost indispensable in conventional methods. [Means for Solving the Problems] A method for producing an axially asymmetric phosphorus compound represented by the general formula (1), comprising a cycloaddition reaction of a compound having a triple bond with the use of a catalyst containing rhodium metal and an optically active bisphosphine. (In the formula (1), R1 and R2 may be the same or different and independently are an alkyl group optionally having a substituent group, a cycloalkyl group optionally having a substituent group, an aryl group optionally having a substituent group, an alkoxy group optionally having a substituent group or an aryloxy group optionally having a substituent group; * is axial asymmetry.Type: ApplicationFiled: March 7, 2011Publication date: September 8, 2011Inventors: Ken TANAKA, Tohru Yokozawa, Tomohiko Hakamata
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Publication number: 20100036149Abstract: The present invention provides an industrially advantageous production method of optically active tetrahydroquinolines of formula (1), which comprises: 1) a step of reacting a ?-ketoester of formula (2) with an amine of formula (3) to produce an enaminoester of formula (4); 2) a step of subjecting the enaminoester of formula (4) above obtained in 1) to asymmetric hydrogenation to produce an optically active ?-amino acid derivative of formula (5); 3) a step of amidating the optically active ?-amino acid derivative (5) above obtained in 2) to produce an amide of formula (6); 4) a step of alkoxycarbonylating the amide of formula (6) above obtained in 3) to produce a compound of formula (7); and 5) a step of subjecting the compound of formula (7) above to cyclization to produce the optically active tetrahydroquinoline of formula (1).Type: ApplicationFiled: August 31, 2009Publication date: February 11, 2010Applicant: TAKASAGO INTERNATIONAL COPORATIONInventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
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Patent number: 7601842Abstract: The present invention provides an industrially advantageous production method of optically active tetrahydroquinolines of formula (1), which comprises: 1) a step of reacting a ?-ketoester of formula (2) ?with an amine of formula (3) ?to produce an enaminoester of formula (4); 2) a step of subjecting the enaminoester of formula (4) above obtained in 1) to asymmetric hydrogenation to produce an optically active ?-amino acid derivative of formula (5); 3) a step of amidating the optically active ?-amino acid derivative (5) above obtained in 2) to produce an amide of formula (6); 4) a step of alkoxycarbonylating the amide of formula (6) above obtained in 3) to produce a compound of formula (7); ?and 5) a step of subjecting the compound of formula (7) above to cyclization to produce the optically active tetrahydroquinoline of formula (1).Type: GrantFiled: February 17, 2004Date of Patent: October 13, 2009Assignee: Takasago International CorporationInventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
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Publication number: 20090227805Abstract: Problem to be Solved: To provide an axially asymmetric optically active biarylphosphorus compound that can easily produced without the step of optical resolution which was almost indispensable in conventional methods. Solution: A method for producing an axially asymmetric phosphorus compound represented by the general formula (1), comprising a cycloaddition reaction of a compound having a triple bond with the use of a catalyst containing rhodium metal and an optically active bisphosphine. (In the formula, J is an oxygen atom, a sulfur atom or BH3; R1 and R2 independently are an alkyl, cycloalkyl, aryl, alkoxy and aryloxy group; a1 and a2 independently are 0 or 1; R3 to R10 independently are an alkyl, cycloalkyl, aryl, alkoxy and aryloxy group; two among R3 to R10 may form a ring; and * is axial asymmetry.Type: ApplicationFiled: March 3, 2009Publication date: September 10, 2009Inventors: Ken Tanaka, Goushi Nishida, Tohru Yokozawa, Yukinori Yusa
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Publication number: 20090221851Abstract: The present invention is a process for producing optically active aminophosphinylbutanoic acids represented by the formula (2) (in the formula (2), R1 represents an alkyl group having 1 to 4 carbon atom(s), R2 represents hydrogen atom or an alkyl group having 1 to 4 carbon atom(s), R3 represents an alkyl group having 1 to 4 carbon atom(s), an alkoxy group having 1 to 4 carbon atom(s), an aryl group, an aryloxy group, or a benzyloxy group, and R4 represents hydrogen atom or an alkyl group having 1 to 4 carbon atom(s); and * represents an asymmetric carbon atom), wherein a compound represented by the formula (1) (in the formula (1), R1 represents an alkyl group having 1 to 4 carbon atom(s), R2 represents hydrogen atom or an alkyl group having 1 to 4 carbon atom(s), R3 represents an alkyl group having 1 to 4 carbon atom(s), an alkoxy group having 1 to 4 carbon atom(s), an aryl group, an aryloxy group, or a benzyloxy group, and R4 represents hydrogen atom or an alkyl group having 1 to 4 carbon atom(s)) iType: ApplicationFiled: September 3, 2007Publication date: September 3, 2009Inventors: Nobuto Minowa, Nozomu Nakanishi, Masaaki Mitomi, Hideki Nara, Tohru Yokozawa
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Patent number: 7312347Abstract: Provided is a method for producing an optically active compound, in more detail, for producing an optically active compound by asymmetric hydrogenation in a high yield and asymmetric yield. The present invention also provides a catalyst for asymmetric synthesis for the above production method, especially a catalyst for asymmetric hydrogenation, containing a transition metal complex. Further, the present invention provides a new diphosphine compound useful as a ligand of the above transition metal complex and a new transition metal complex containing the above diphosphine compound. The present invention relates to a diphosphine compound represented by the following formula (1): a transition metal complex using the compound, a catalyst for asymmetric synthesis comprising the above transition metal complex and a method for producing an optically active compound using the above catalyst for asymmetric synthesis.Type: GrantFiled: September 22, 2006Date of Patent: December 25, 2007Assignee: Takasago International CorporationInventors: Takahiro Fujiwara, Tohru Yokozawa
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Publication number: 20070142472Abstract: The present invention relates to a process for producing an optically active 3-(4-hydroxyphenyl)propionic acid useful as intermediates for medicines, through short steps in good yield and with high optical purity.Type: ApplicationFiled: November 26, 2004Publication date: June 21, 2007Inventors: Tohru Yokozawa, Hideo Shimizu, Takahiro Fujiwara, Yasunori Ino
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Publication number: 20070073065Abstract: Provided is a method for producing an optically active compound, in more detail, for producing an optically active compound by asymmetric hydrogenation in a high yield and asymmetric yield. The present invention also provides a catalyst for asymmetric synthesis for the above production method, especially a catalyst for asymmetric hydrogenation, containing a transition metal complex. Further, the present invention provides a new diphosphine compound useful as a ligand of the above transition metal complex and a new transition metal complex containing the above diphosphine compound. The present invention relates to a diphosphine compound represented by the following formula (1): a transition metal complex using the compound, a catalyst for asymmetric synthesis comprising the above transition metal complex and a method for producing an optically active compound using the above catalyst for asymmetric synthesis.Type: ApplicationFiled: September 22, 2006Publication date: March 29, 2007Applicant: Takasago International CorporationInventors: Takahiro Fujiwara, Tohru Yokozawa
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Publication number: 20060122225Abstract: The present invention provides an industrially advantageous production method of optically active tetrahydroquinolines of formula (1), which comprises: 1) a step of reacting a ?-ketoester of formula (2) ?with an amine of formula (3) ?to produce an enaminoester of formula (4); 2) a step of subjecting the enaminoester of formula (4) above obtained in 1) to asymmetric hydrogenation to produce an optically active ?-amino acid derivative of formula (5); 3) a step of amidating the optically active ?-amino acid derivative (5) above obtained in 2) to produce an amide of formula (6); 4) a step of alkoxycarbonylating the amide of formula (6) above obtained in 3) to produce a compound of formula (7); ?and 5) a step of subjecting the compound of formula (7) above to cyclization to produce the optically active tetrahydroquinoline of formula (1).Type: ApplicationFiled: February 17, 2004Publication date: June 8, 2006Inventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
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Patent number: 6984738Abstract: The present invention is to provide a process for producing an optically active amino alcohol which is useful for the synthesis of natural substances and as an intermediate for drugs and agricultural chemicals in a high yield, a high selectivity and an economical manner with a good working efficiency and the present invention relates to a process for producing an optically active amino alcohol represented by the following formula (2) (in the formula, R1 is a hydrocarbon group, a substituted hydrocarbon group, an aromatic heterocyclic group, a substituted aromatic heterocyclic group, an aliphatic heterocyclic group or a substituted aliphatic heterocyclic group; R2 and R3 each independently is hydrogen atom, a hydrocarbon group, a substituted hydrocarbon group, an acyl group, an acyloxy group, an alkyloxycarbonyl group, an aralkyloxycarbonyl group, an aryloxycarbonyl group, an aromatic heterocyclic group, a substituted aromatic heterocyclic group, an aliphatic heterocyclic group or a substituted aliphatic hType: GrantFiled: October 17, 2003Date of Patent: January 10, 2006Inventors: Tohru Yokozawa, Kenji Yagi, Takao Saito
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Patent number: 6794328Abstract: The present invention provides a novel phosphine compound, specifically to provide a novel phosphine compound useful as a ligand for the above catalysts, in particular, a novel catalyst having an excellent performance (chemical selectivity, enantio-selectivity, catalytic activity) as a catalyst for asymmetric synthetic reactions, particularly asymmetric hydrogenation. A diphosphine compound represented by the general formula (1): wherein R1 and R2 each independently represents a lower alkyl group, a cycloalkyl group, an unsubstituted or substituted phenyl group, or a five-membered heteroaromatic ring residue.Type: GrantFiled: June 3, 2003Date of Patent: September 21, 2004Assignee: Takasago International CorporationInventors: Tohru Yokozawa, Takao Saito
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Publication number: 20040082794Abstract: The present invention is to provide a process for producing an optically active amino alcohol which is useful for the synthesis of natural substances and as an intermediate for drugs and agricultural chemicals in a high yield, a high selectivity and an economical manner with a good working efficiency and the present invention relates to a process for producing an optically active amino alcohol represented by the following formula (2) 1Type: ApplicationFiled: October 17, 2003Publication date: April 29, 2004Inventors: Tohru Yokozawa, Kenji Yagi, Takao Saito
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Publication number: 20030228977Abstract: The present invention provides a novel phosphine compound, specifically to provide a novel phosphine compound useful as a ligand for the above catalysts, in particular, a novel catalyst having an excellent performance (chemical selectivity, enantio-selectivity, catalytic activity) as a catalyst for asymmetric synthetic reactions, particularly asymmetric hydrogenation.Type: ApplicationFiled: June 3, 2003Publication date: December 11, 2003Applicant: TAKASAGO INTERNATIONAL CORPORATIONInventors: Tohru Yokozawa, Takao Saito
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Patent number: 6492545Abstract: A novel process in which an optically active alcohol compound having a desired absolute configuration and a high optical purity can be obtained by asymmetrically hydrogenating a &bgr;-keto acid compound through a simple operation. An optically active alcohol represented by general formula (III) as defined is obtained by asymmetrically hydrogenating a &bgr;-keto ester compound represented by general formula (I) as defined in the presence of at least one ruthenium complex having as a ligand an optically active tertiary diphosphine compound represented by general formula (II) as defined.Type: GrantFiled: July 23, 2001Date of Patent: December 10, 2002Assignee: Takasago International CorporationInventors: Takao Saito, Tohru Yokozawa, Kazuhiko Matsumura, Noboru Sayo
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Patent number: 6472539Abstract: A process for producing a diphosphine oxide or diphosphonate represented by formula (1) as defined, which comprises treating, with a base, a phosphine compound represented by formula (2) as defined and adding the thus-treated phosphine compound to a nonpolar solvent having an oxidative metal compound suspended therein so as to effect dimerization. The present invention makes it possible to produce, conveniently, in a high yield and safely, a diphosphine oxide or diphosphonate which is an intermediate for producing a diphosphine compound useful as a ligand of a metal complex serving as a catalyst for asymmetric synthesis reaction.Type: GrantFiled: July 6, 2001Date of Patent: October 29, 2002Assignee: Takasago International CorporationInventors: Tohru Yokozawa, Takao Saito, Noboru Sayo, Takero Ishizaki