Patents by Inventor Randolph C. Wirsching

Randolph C. Wirsching 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 production of 2-fluoropurine derivatives
    Patent number: 5696255
    Abstract: This invention relates to a process for the production of 2-fluoropurine derivatives from 2-aminopurine derivatives, which are reacted in HF/pyridine or HF/pyridine/H.sub.2 O in the presence of a nitrite.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: December 9, 1997
    Assignee: Schering Aktiengesellschaft
    Inventors: Helmut Vorbruggen, Konrad Krolikiewicz, Randolph C. Wirsching, John G. Bauman
  • Process for the preparation of fludarabine or fludarabine phosphate from guanosine
    Patent number: 5668270
    Abstract: A process for the production of fludarabine or fludarabine phosphate is provided, wherein the nucleoside guanosine or a suitable derivative is employed as the starting material. The guanosine starting material is subjected to (a) conversion of the 6-keto group into a 6-amino group, (b) conversion of the 2-amino group to a 2-fluoro group, and (c) conversion of the ribofuranosyl moiety to an arabinofuranosyl moiety. Steps (a), (b), and (c) can be performed individually or concomitantly and in any sequence.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: September 16, 1997
    Assignee: Schering Aktiengesellschaft
    Inventors: John G. Bauman, Randolph C. Wirsching
  • Process for the preparation of fludarabine or fludarabine phosphate from guanosine
    Patent number: 5602246
    Abstract: A process for the production of fludarabine or fludarabine phosphate is provided, wherein the nucleoside guanosine or a suitable derivative is employed as the starting material. The guanosine starting material is subjected to (a) conversion of the 6-keto group into a 6-amino group, (b) conversion of the 2-amino group to a 2-fluoro group, and (c) conversion of the ribofuranosyl moiety to an arabinofuranosyl moiety. Steps (a), (b), and (c) can be performed individually or concomitantly and in any sequence.
    Type: Grant
    Filed: November 25, 1992
    Date of Patent: February 11, 1997
    Assignee: Schering Aktiengesellschaft
    Inventors: John G. Bauman, Randolph C. Wirsching
  • 6-azido-2-fluoropurine, useful in the synthesis of nucleosides
    Patent number: 5180824
    Abstract: This invention pertains to novel methods of synthesizing fludarabine, fludarabine phosphate and related nucleoside pharmacologic agents utilizing 6-azido-2-fluoropurine as a novel intermediate.In particular this invention pertains to a synthesis of fludarabine where the relatively low yield fluorination step is done before the costly coupling step.
    Type: Grant
    Filed: November 29, 1990
    Date of Patent: January 19, 1993
    Assignee: Berlex Biosciences Inc.
    Inventors: John G. Bauman, Randolph C. Wirsching