Patents by Inventor Juergen Fleckenstein

Juergen Fleckenstein 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 biotin
    Patent number: 6291681
    Abstract: The present invention is directed to a process for the production of 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid and of 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid anhydride, starting from meso-2,3-bis(benzylamino)succinic acid dialkali metal salt. The process involves reacting meso-2,3-bis(benzylamino)succinic acid dialkali metal salt with phenyl chloroformate in a monophasic solvent system consisting of an about 2:1 to 1:1 mixture of a water-miscible ether and an aqueous alkali metal hydroxide solution, at a temperature not exceeding about 40° C.
    Type: Grant
    Filed: February 9, 2001
    Date of Patent: September 18, 2001
    Assignee: Roche Vitamins Inc.
    Inventors: Juergen Fleckenstein, Bernd Kraemer, Joachim Veits
  • Process for preparing biotin
    Publication number: 20010020101
    Abstract: The present invention is directed to a process for the production of 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid and of 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid anhydride, starting from meso-2,3-bis(benzylamino)succinic acid dialkali metal salt. The process involves reacting meso-2,3-bis(benzylamino)succinic acid dialkali metal salt with phenyl chloroformate in a monophasic solvent system consisting of an about 2:1 to 1:1 mixture of a water-miscible ether and an aqueous alkali metal hydroxide solution, at a temperature not exceeding about 40° C.
    Type: Application
    Filed: February 9, 2001
    Publication date: September 6, 2001
    Applicant: F. Hoffmann-La Roche AG
    Inventors: Juergen Fleckenstein, Bernd Kraemer, Joachim Veits