Patents by Inventor David Daqiang Xu

David Daqiang Xu 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 certain substituted caprolactams
    Patent number: 6545148
    Abstract: The present invention relates to an improved process for preparing certain substituted caprolactam compounds which comprises acylating an aminocaprolactam compound with a lactone compound in the presence of a weak base and a polar, organic solvent, and hydrolyzing the resultant diamide compound in a mixture of solvents to obtain the desired caprolactam compound.
    Type: Grant
    Filed: March 11, 2002
    Date of Patent: April 8, 2003
    Assignee: Novartis AG
    Inventors: David Daqiang Xu, Wenming Liu
  • Process for preparing certain substituted caprolactams
    Publication number: 20020128474
    Abstract: The present invention relates to an improved process for preparing certain substituted caprolactam compounds which comprises acylating an aminocaprolactam compound with a lactone compound in the presence of a weak base and a polar, organic solvent, and hydrolyzing the resultant diamide compound in a mixture of solvents to obtain the desired caprolactam compound.
    Type: Application
    Filed: March 11, 2002
    Publication date: September 12, 2002
    Inventors: David Daqiang Xu, Wenming Liu