Patents by Inventor Zhisong Cao

Zhisong Cao 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).

  • Derivatives of camptothecin and methods of treating cancer using these derivatives
    Patent number: 5968943
    Abstract: Derivatives of camptothecin are disclosed and are represented by the general formula: ##STR1## wherein when R.sub.2 is H, R.sub.1 is a C.sub.2 -C.sub.4 alkyl group, a C.sub.6 -C.sub.15 alkl group, a C.sub.3 -C.sub.8 cycloalkyl group, a C.sub.2 -C.sub.15 alkenyl group or a C.sub.2 -C.sub.15 epoxy group; and when R.sub.2 is a nitro group, R.sub.1 is a C.sub.1 -C.sub.15 alkyl group, a C.sub.2 -C.sub.15 alkenyl group, a C.sub.3 -C.sub.8 cycloalkyl group, or an epoxy group. Processes for mailing these derivatives and for using them in cancer treatment are also disclosed.
    Type: Grant
    Filed: February 25, 1998
    Date of Patent: October 19, 1999
    Assignee: The Stehlin Foundation for Cancer Research
    Inventors: Zhisong Cao, Beppino C. Giovanella
  • Methods of preparing and purifying 9-nitro-20-camptothecin
    Patent number: 5922877
    Abstract: A method is disclosed for the preparation of 9-nitrocamptothecin which involves reacting 20-camptothecin with at least one inorganic nitrate salt and at least one acid effective in catalyzing the formation of a nitronium ion, where the reaction occurs at a temperature and for a time sufficient to form the 9-nitrocamptothecin. Also, methods of further purifying the 9-nitrocamptothecin by column chromatography or by reprecipatation is also disclosed.
    Type: Grant
    Filed: August 5, 1997
    Date of Patent: July 13, 1999
    Assignee: The Stehlin Foundation for Cancer Research
    Inventor: Zhisong Cao
  • Derivatives of camptothecin and methods of treating cancer using these derivatives
    Patent number: 5731316
    Abstract: Derivatives of camptothecin are disclosed and are represented by the general formula: ##STR1## wherein when R.sub.2 is H, R.sub.1 is a C.sub.2 -C.sub.15 alkyl group, a C.sub.2 -C.sub.15 alkenyl group or an epoxy group; and when R.sub.2 is a nitro group, R.sub.1 is a C.sub.1 -C.sub.15 alkyl group, a C.sub.1 -C.sub.15 alkenyl group or an epoxy group. Processes for making these derivatives and for using them in cancer treatment are also disclosed.
    Type: Grant
    Filed: January 30, 1996
    Date of Patent: March 24, 1998
    Assignee: The Stehlin Foundation for Cancer Research
    Inventors: Zhisong Cao, Beppino C. Giovanella