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).

  • Patent number: 9079931
    Abstract: 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: Grant
    Filed: December 14, 2010
    Date of Patent: July 14, 2015
    Assignee: Takasago International Corporation
    Inventors: Hideki Nara, Tohru Yokozawa
  • Publication number: 20130041151
    Abstract: 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: Application
    Filed: December 14, 2010
    Publication date: February 14, 2013
    Applicant: TAKASAGO INTERNATIONAL CORPORATION
    Inventors: Hideki Nara, Tohru Yokozawa
  • Patent number: 8222433
    Abstract: 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: Grant
    Filed: March 7, 2011
    Date of Patent: July 17, 2012
    Assignees: National University Corporation Tokyo University of Agriculture and Technology, Takasago International Corporation
    Inventors: Ken Tanaka, Tohru Yokozawa, Tomohiko Hakamata
  • Patent number: 8188307
    Abstract: 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: Grant
    Filed: August 31, 2009
    Date of Patent: May 29, 2012
    Assignee: Takasago International Corporation
    Inventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
  • Patent number: 8076503
    Abstract: 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: Grant
    Filed: September 3, 2007
    Date of Patent: December 13, 2011
    Assignees: Meiji Seika Pharma Co., Ltd., Takasago International Corporation
    Inventors: Nobuto Minowa, Nozomu Nakanishi, Masaaki Mitomi, Hideki Nara, Tohru Yokozawa
  • Publication number: 20110218345
    Abstract: [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: Application
    Filed: March 7, 2011
    Publication date: September 8, 2011
    Inventors: Ken TANAKA, Tohru Yokozawa, Tomohiko Hakamata
  • Publication number: 20100036149
    Abstract: 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: Application
    Filed: August 31, 2009
    Publication date: February 11, 2010
    Applicant: TAKASAGO INTERNATIONAL COPORATION
    Inventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
  • Patent number: 7601842
    Abstract: 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: Grant
    Filed: February 17, 2004
    Date of Patent: October 13, 2009
    Assignee: Takasago International Corporation
    Inventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
  • Publication number: 20090227805
    Abstract: 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: Application
    Filed: March 3, 2009
    Publication date: September 10, 2009
    Inventors: Ken Tanaka, Goushi Nishida, Tohru Yokozawa, Yukinori Yusa
  • Publication number: 20090221851
    Abstract: 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)) i
    Type: Application
    Filed: September 3, 2007
    Publication date: September 3, 2009
    Inventors: Nobuto Minowa, Nozomu Nakanishi, Masaaki Mitomi, Hideki Nara, Tohru Yokozawa
  • Patent number: 7312347
    Abstract: 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: Grant
    Filed: September 22, 2006
    Date of Patent: December 25, 2007
    Assignee: Takasago International Corporation
    Inventors: Takahiro Fujiwara, Tohru Yokozawa
  • Publication number: 20070142472
    Abstract: 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: Application
    Filed: November 26, 2004
    Publication date: June 21, 2007
    Inventors: Tohru Yokozawa, Hideo Shimizu, Takahiro Fujiwara, Yasunori Ino
  • Publication number: 20070073065
    Abstract: 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: Application
    Filed: September 22, 2006
    Publication date: March 29, 2007
    Applicant: Takasago International Corporation
    Inventors: Takahiro Fujiwara, Tohru Yokozawa
  • Publication number: 20060122225
    Abstract: 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: Application
    Filed: February 17, 2004
    Publication date: June 8, 2006
    Inventors: Takashi Moroi, Tsukasa Sotoguchi, Kazuhiko Matsumura, Motonobu Takenaka, Wataru Kuriyama, Toshiyuki Murayama, Hideki Nara, Tohru Yokozawa, Kenji Yagi
  • Patent number: 6984738
    Abstract: 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 h
    Type: Grant
    Filed: October 17, 2003
    Date of Patent: January 10, 2006
    Inventors: Tohru Yokozawa, Kenji Yagi, Takao Saito
  • Patent number: 6794328
    Abstract: 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: Grant
    Filed: June 3, 2003
    Date of Patent: September 21, 2004
    Assignee: Takasago International Corporation
    Inventors: Tohru Yokozawa, Takao Saito
  • Publication number: 20040082794
    Abstract: 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) 1
    Type: Application
    Filed: October 17, 2003
    Publication date: April 29, 2004
    Inventors: Tohru Yokozawa, Kenji Yagi, Takao Saito
  • Publication number: 20030228977
    Abstract: 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: Application
    Filed: June 3, 2003
    Publication date: December 11, 2003
    Applicant: TAKASAGO INTERNATIONAL CORPORATION
    Inventors: Tohru Yokozawa, Takao Saito
  • Patent number: 6492545
    Abstract: 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: Grant
    Filed: July 23, 2001
    Date of Patent: December 10, 2002
    Assignee: Takasago International Corporation
    Inventors: Takao Saito, Tohru Yokozawa, Kazuhiko Matsumura, Noboru Sayo
  • Patent number: 6472539
    Abstract: 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: Grant
    Filed: July 6, 2001
    Date of Patent: October 29, 2002
    Assignee: Takasago International Corporation
    Inventors: Tohru Yokozawa, Takao Saito, Noboru Sayo, Takero Ishizaki