Patents by Inventor Myeong S. Yoon

Myeong S. Yoon 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 the preparation of cephem derivatives
    Patent number: 5317099
    Abstract: A process for preparing B-lactam derivatives of the formula (I): ##STR1## wherein R.sup.1 represents hydrogen or a metal salt; and R.sup.2 represents hydrogen, acetoxy methyl, (2,5-dihydro-2-methyl-6-hydroxy-5-oxo-as-triazin-3-yl)thiomethyl or (1-methyl-1-H-tetrazol-5-yl)thiomethyl is disclosed. This process comprises the steps of (a) reacting triphenylphosphine and hexachloroethane or carbon tetrachloride with 2-(2-aminothiazol-4-yl)-2-syn-methoxyimino acetic acid in an organic solvent to give the corresponding acyloxyphosphonium chloride derivative of the formula: ##STR2## (b) acylating a previously silylated derivative of 7-ACA with this acyloxyphosphonium chloride derivative without its isolation.
    Type: Grant
    Filed: October 13, 1992
    Date of Patent: May 31, 1994
    Assignee: Cheil Foods & Chemicals, Inc.
    Inventors: Kwang H. Lee, Dong H. Ko, Young J. Kim, Myung X. Xiang, Myeong S. Yoon