Patents by Inventor Dae Il Hwang

Dae Il Hwang 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 optically pure(S)-3,4-dihydroxybutyric acid derivatives
    Patent number: 6221639
    Abstract: The present invention relates to a process for preparing optically pure (S)-3,4-dihydroxybutyric acid derivatives expressed by the following Formula 1 and more particularly, to a process that enables preparing optically pure (S)-3,4-dihydroxybutyric acid derivatives economically in large quantities, by: (a) Preparing &agr;-(1,4)-linked oligosaccharide with adequate sugar distribution by reacting amylopectin which is easily available from natural product with enzyme under a specific condition; and (b) Performing oxidation and esterification sequentially under a specific condition. wherein, R represents linear or branched alkyl group with 1˜5 carbon atoms.
    Type: Grant
    Filed: July 23, 1999
    Date of Patent: April 24, 2001
    Assignee: Samsung Fine Chemicals Co., Ltd.
    Inventors: Yik-haeng Cho, Jongpil Chun, Young Mi Park, Kyoung Rok Roh, Hosung Yu, Dae Il Hwang
  • Process for preparing optically pure (S)-3-hydroxy-.gamma.-butyrolactone
    Patent number: 6124122
    Abstract: The present invention relates to a process for preparing optically pure (S)-3-hydroxy-.gamma.-butyrolactone expressed by the following Formula 1 and more particularly, to a process that enables preparing optically pure (S)-3-hydroxy-.gamma.-butyrolactone economically in large quantities, by:(a) Preparing .alpha.-(1,4) linked oligosaccharide with adequate sugar distribution by reacting amylopectin which is easily available from natural product with enzyme under a specific condition; and(b) Performing oxidation, esterification and cyclization sequentially under a specific condition.
    Type: Grant
    Filed: July 23, 1999
    Date of Patent: September 26, 2000
    Assignee: Samsung Fine Chemicals Co., Ltd.
    Inventors: Jongpil Chun, Yik-haeng Cho, Young Mi Park, Kyoung Rok Roh, Hosung Yu, Dae Il Hwang