Patents by Inventor Teruo Yonekawa

Teruo Yonekawa 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).

  • Adduct salts of novel substituted benzylamines and a process for optically resolving them
    Patent number: 5856579
    Abstract: A process for optical resolution of a racemic substituted benzylamine is provided that involves reacting the racemic substituted benzylamine in a solvent with an optically active N-acyl-phenylalanine, -aspartic acid, or -glutamic acid, and separating the diastereomers formed by making use of the difference in the mutual solubilities of the two diastereomer salts which are generated therein.
    Type: Grant
    Filed: October 15, 1996
    Date of Patent: January 5, 1999
    Assignee: Ajinomoto Co., Inc.
    Inventors: Tadashi Takemoto, Toyoto Hijiya, Teruo Yonekawa
  • Addition salt of acyl-amino acid and .alpha.-aryl amine and process for optical resolution of .alpha.-arylamine
    Patent number: 5629450
    Abstract: To produce optically active .alpha.-arylalkylamine from optically impure .alpha.-arylalkylamine.Optically impure .alpha.-arylalkylamine is mixed with optically active N-acyl-aspartic acid or glutamic acid in a solvent and the resulting two types of diastereomer salts are optically resolved utilizing difference in solubility.
    Type: Grant
    Filed: March 21, 1995
    Date of Patent: May 13, 1997
    Assignee: Ajinomoto Co., Inc.
    Inventors: Toyoto Hijiya, Teruo Yonekawa, Tadashi Takemoto
  • Method for recovering L-phenylalanine
    Patent number: 5616766
    Abstract: The present invention provides crystals of L-phenylalanine monomethyl sulfate which have low solubility compared to L-tyrosine and D-phenylalanine. The L-phenylalanine monomethylsulfate crystals are obtained by subjecting a solution containing monomethyl sulfuric acid and phenylalanine to crystallization.Further, the present invention also provides a process for recovering L-phenylalanine from a water layer by neutralizing the esterified reaction, extracting an ester of L-phenylalanine therefrom with an organic solvent, and recovering remaining L-phenylalanine in the water layer as L-phenylalanine monomethylsulfate. L-phenylalanine monomethyl sulfate is obtained by esterifying L-phenylalanine and methanol in the presence of sulfuric acid, neutralizing the esterified solution with a base in the presence of water, extracting the produced L-phenylalanine methyl ester from the neutralized solution with an organic solvent, and then crystallized the resultant water layer under acidic condition.
    Type: Grant
    Filed: May 16, 1995
    Date of Patent: April 1, 1997
    Assignee: Ajinomoto Co., Inc.
    Inventors: Tadashi Takemoto, Toyoto Hijiya, Teruo Yonekawa, Chiaki Mochizuki
  • Method for recovering L-phenylalanine
    Patent number: 5466864
    Abstract: The present invention provides crystals of L-phenylalanine monomethyl sulfate which have low solubility compared to L-tyrosine and D-phenylalanine. The L-phenylalanine monomethylsulfate crystals are obtained by subjecting a solution containing monomethyl sulfuric acid and phenylalanine to crystallization.Further, the present invention also provides a process for recovering L-phenylalanine from a water layer by neutralizing the esterified reaction, extracting an ester of L-phenylalanine therefrom with an organic solvent, and recovering remaining L-phenylalanine in the water layer as L-phenylalanine monomethylsulfate. L-phenylalanine monomethyl sulfate is obtained by esterifying L-phenylalanine and methanol in the presence of sulfuric acid, neutralizing the esterified solution with a base in the presence of water, extracting the produced L-phenylalanine methyl ester from the neutralized solution with an organic solvent, and then crystallized the resultant water layer under acidic condition.
    Type: Grant
    Filed: February 2, 1994
    Date of Patent: November 14, 1995
    Assignee: Ajinomoto Co., Inc.
    Inventors: Tadashi Takemoto, Toyoto Hijiya, Teruo Yonekawa, Chiaki Mochizuki