Patents by Inventor Randall A. Roehl

Randall A. Roehl 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 pyridine-2,3-dicarboxylic acids
    Patent number: 5166060
    Abstract: Pyridine-2,3-dicarboxylic acids are prepared by the action of 2,3-dihydroxybenzoate-3,4-dioxygenase on 2,3-dihydroxybenzoic acids in a liquid medium which lacks active decarboxylase and which has a pH from 4 to 9, an ionic strength below about 1 molar, and a low concentration of metal cations and complex anions. In close temporal proximity, the 2-hydroxy-3-carboxymuconic acid semialdehyde which forms is allowed to react with a source of ammonia or a primary amine, avoiding substantial decarboxylation.
    Type: Grant
    Filed: March 31, 1989
    Date of Patent: November 24, 1992
    Assignee: Celgene Corporation
    Inventors: Randall A. Roehl, George W. Matcham, David I. Stirling