Patents by Inventor Takeshi Tozawa

Takeshi Tozawa 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: 5607785
    Abstract: Disclosed herein are several aspects processes of preparing a polymer electrolyte electrochemical cell in which supply of a reaction gas and discharge of an obtained gas can be smoothly conducted. This can be achieved by forming through apertures in a cathode or by forming a gradient of ion exchange resin concentration of a catalyst particle cluster size.
    Type: Grant
    Filed: October 11, 1995
    Date of Patent: March 4, 1997
    Assignees: Tanaka Kikinzoku Kogyo K.K., M. Watanabe, Stonehart Associates Inc.
    Inventors: Takeshi Tozawa, Nobuhito Toshima
  • Patent number: 5338874
    Abstract: Disclosed herein is cis-oxalato (trans-1-1,2-cyclohexanediamine) Pt(II) optically high purity. Because of its complete optical purity, the compound is effective as raw material of such a medicine as a carcinostatic agent. The complete optical purity of the above compound may be proved by comparing the respective melting points of the cis-oxalato (trans-1-1,2-cyclohexanediamine).
    Type: Grant
    Filed: April 7, 1993
    Date of Patent: August 16, 1994
    Assignee: Tanaka Kikinzoku Kogyo K.K.
    Inventors: Chihiro Nakanishi, Yuko Ohnishi, Junji Ohnishi, Junichi Taniuchi, Koji Okamoto, Takeshi Tozawa
  • Patent number: 5298642
    Abstract: Disclosed herein is a process of optically resoluting optically active platinum complex compounds which comprises optically resoluting a d-isomer and an 1-isomer of a cis-Pt(II) complex of a 1,2-cyclohexanediamine isomer characterized in that the mixture of the d-isomer and the 1-isomer is optically resoluted by means of high performance liquid chromatography employing a column packed with a chiral filler.The chiral filler include, for example, a cellulose ester derivative, a cellulose carbamate derivative, an amylose carbamate derivative, a polymethacryl acid ester and .beta.- and .gamma.-cyclodextrin.According to the present invention, the optical resolution of a platinum complex compound essentially consisting of the mixture of two optical isomers which cannot be resoluted in accordance with a normal resolution method due to the small structural difference can be easily performed utilizing the characteristics of a chiral filler.
    Type: Grant
    Filed: April 7, 1993
    Date of Patent: March 29, 1994
    Assignee: Tanaka Kikinzoku Kogyo K.K.
    Inventors: Takeshi Tozawa, Yasunobu Komoda, Junji Ohnishi, Yukie Masuda, Junichi Taniuchi, Chihiro Nakanishi, Koji Okamoto