Patents by Inventor Noriyoshi Numoto

Noriyoshi Numoto 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).

  • Process for preparing valproic acid
    Patent number: 5101070
    Abstract: A process for preparing valproic acid which comprises:(I) producing a 2,2-dipropyl acetoacetic acid ester from an acetoacetic acid ester,(II) deacetylating the 2,2-dipropyl acetoacetic acid ester with an alcohol to give a valproic acid ester, and(III) hydrolyzing the valproic acid ester. In the process of the present invention, valproic acid can be prepared in a high yield as not less than 85% by mole and by-products such as .alpha.-propyl-.beta.-ethyl acrylic acid and its esters which cannot be easily separated from valproic acid, are not entirely produced.
    Type: Grant
    Filed: July 5, 1988
    Date of Patent: March 31, 1992
    Assignee: Nippon Gohsei Kagaku Kogyo Kabushiki Kaisha
    Inventors: Toshio Yamamoto, Akira Yamashita, Noriyoshi Numoto