Patents by Inventor David R. Carver

David R. Carver 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).

  • Method of reducing vat dyes and the process of dyeing fabrics therein
    Patent number: 5350425
    Abstract: A process for reducing vat dyes, such as indigo, into their leuco form by placing a metal, such as aluminum, in water in the presence of a reduction facilitator to form a first solution after which a vat dye having the general structure O.dbd.C(--C.dbd.C--).sub.N C.dbd.O where N=1, 2 or 4 is mixed with the first solution to form a dye solution where substantially all of the vat dye is reduced to its soluble leuco form having the general structure HO--C.dbd.(C--C).sub.N .dbd.C--OH. The process includes dyeing fabric in the dye solution. the reduction facilitator may be a base, for example that produced hydroxide ions in water, and the first solution as well as the dye solution can be a basic solution. The soluble leuco can be isolated from the dye solution and dissolved in a non-aqueous solution. Prior to mixing the vat dye in water, it may first be dissolved in a solvent miscible with water.
    Type: Grant
    Filed: August 9, 1993
    Date of Patent: September 27, 1994
    Inventor: David R. Carver
  • Method of using ion exchange media to increase taxane yields
    Patent number: 5281727
    Abstract: The present invention is a method that uses an absorption column for the cleavage and recovery of taxanes, which are not normally detected as free taxanes. The method processes a first solution that contains standard detectable taxanes and other undetectable taxane compounds to generate a second solution that contains a higher percentage of detectable standard taxane then the first solution. The first step of this method is loading a column having a first opening and a second opening with an ion exchange media. The next step is placing the first solution in the first opening of the column so that the first solution passes through the ion exchange media in the column and flows to the second opening. Thus, the taxane compounds are converted to standard taxanes by an ion exchange reaction and the second solution is formed.
    Type: Grant
    Filed: November 27, 1992
    Date of Patent: January 25, 1994
    Assignee: NaPro BioTherapeutics, Inc.
    Inventors: David R. Carver, Timothy R. Prout, Christopher T. Workman, Donia L. Henderson, Charles L. Hughes
  • Processes of converting taxanes into 10-deacetylbaccatin III
    Patent number: 5256801
    Abstract: A process for the preparation of a compound of formula (I) ##STR1## comprising contacting a mixture containing at least one taxane compound having an ester linkage at the C-13 position with at least one borohydride reducing salt in a reaction solvent in the presence of a Lewis acid.
    Type: Grant
    Filed: December 4, 1992
    Date of Patent: October 26, 1993
    Assignee: NaPro BioTherapeutics, Inc.
    Inventors: David R. Carver, Timothy R. Prout, Hernita A. Ewald, Donia L. Henderson
  • Processes of converting taxanes into baccatin III
    Patent number: 5202448
    Abstract: The present invention relates to a process of converting partially purified taxane mixtures into Baccatin III. The process for the preparation of Baccatin III includes contacting a mixture containing at least one taxane compound having an ester linkage at the C-13 position with at least one borohydride reducing salt in a reaction solvent in the present of a Lewis acid.
    Type: Grant
    Filed: August 14, 1992
    Date of Patent: April 13, 1993
    Assignee: NaPro BioTherapeutics, Inc.
    Inventors: David R. Carver, Timothy R. Prout, Hernita A. Ewald, Donia L. Henderson