Patents by Inventor Herbert Nagel

Herbert Nagel 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).

  • Resolution of racemic verapamil
    Patent number: 5457224
    Abstract: A process for the resolution of racemic verapamil which comprises reacting the free base of the compound with optically active dibenzoyltartaric acid or ditoluoyltartaric acid in the molar ratio from 1:1 to 1:2 in a methanol/water mixture in the ratio from 1:1 to 3:1 or acetone/water mixture in the ratio from 0.5:1 to 2:1, separating the mixture of diastereomers obtained in this way by crystallization, and then converting the diastereomers into the free bases and these into their salts, if required, with physiologically tolerated acids.
    Type: Grant
    Filed: June 7, 1994
    Date of Patent: October 10, 1995
    Assignee: Knoll Aktiengesellschaft
    Inventors: Oskar Ehrmann, Herbert Nagel