Patents Represented by Attorney Portia Chen

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  • 6-O-alkyl derivatives of erythronolide B
    Patent number: 5919916
    Abstract: Novel 6-O-alkyl derivatives of erythronolide B are provided. A process for the preparation of 6-O-alkyl derivatives of erythronolide B using erythromycin B is also provided. A process for preparing 6-O-alkyl derivatives of erythromycin C using novel 6-O-alkyl derivatives of erythronolide B is further provided.
    Type: Grant
    Filed: December 1, 1997
    Date of Patent: July 6, 1999
    Assignee: Abbott Laboratories
    Inventors: H. Eugene Gracey, Stephen H. Montgomery, David A. Riley, Jih-Hua Liu
  • Process for the preparation of 6-O-methyl erythromycin a using 9-hydroxy erythromycin derivatives
    Patent number: 5892008
    Abstract: The claimed invention provides a novel method of preparing 6-O-methyl erythromycin A. The process comprises the steps of reducing the 9-keto group of erythromycin A to form a 9-hydroxy erythromycin A, protecting the 9-, 2'-, and/or 4"-hydroxyl groups of erythromycin A, selectively methylating the 6-position of the 9-hydroxy erythromycin A derivative, deprotecting the hydroxyl groups and oxidizing the 9-hydroxyl to afford 6-O-methyl erythromycin A.
    Type: Grant
    Filed: December 16, 1997
    Date of Patent: April 6, 1999
    Assignee: Abbott Laboratories
    Inventors: Yi-Yin Ku, David A. Riley, Elaine C. Lee, Jien-Heh Tien
  • Process for N-desmethylating erythromycins and derivatives thereof
    Patent number: 5883236
    Abstract: Disclosed is an improved and efficient process for N-desmethylating the 3'-amino nitrogen of erythromycins and for converting the 3'-N-desmethylated erythromycins into 3'-N-substituted derivatives of 8,9-anhydro-erythromycin 6,9-hemiketals.
    Type: Grant
    Filed: November 19, 1997
    Date of Patent: March 16, 1999
    Assignee: Abbott Laboratories
    Inventors: John E. Hengeveld, Xiaoxing Dong, Ashok K. Gupta, Richard R. Copp, Jr., Ramiya H. Premchandran