Patents by Inventor David J. S. Tsai

David J. S. Tsai 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).

  • Stereoselective Alkylation of Chiral 2-Methly-4 Protected Piperazines
    Publication number: 20100249411
    Abstract: In an illustrative embodiment, the present invention describes the synthesis of the following compound and similar compounds, in high stereochemical purity by a novel stereoselective alkylation process:
    Type: Application
    Filed: March 29, 2010
    Publication date: September 30, 2010
    Inventors: Wenxue Wu, Hongbiao Liao, David J.S. Tsai, David R. Andrews, Dinesh Gala, Gary M. Lee, Martin Lawrence Schwartz, Timothy L. McAllister, Xiaoyong Fu, Donal Maloney, Tiruvettipuram K. Thiruvengadam, Chou-Hang Tann
  • Synthesis of himbacine analogs
    Patent number: 7626045
    Abstract: The present invention relates to an improved process for preparing himbacine analogs. The compounds are useful as thrombin receptor antagonists. The improved process may allow for at least one of easier purification by crystallization, easier scalability, and improved process yield on the desired enantiomer.
    Type: Grant
    Filed: April 23, 2009
    Date of Patent: December 1, 2009
    Assignee: Schering Corporation
    Inventors: Tiruvettipuram K. Thiruvengadam, Tao Wang, Jing Liao, John S. Chiu, David J. S. Tsai, Hong-Chang Lee, Wenxue Wu, Xiaoyong Fu
  • Preparation of pharmaceutical salts
    Patent number: 7534884
    Abstract: In one embodiment, the present invention discloses a process to directly prepare an unequal ratio of rotamers of an acid salt from a basic compound, by creative choice of a solvent medium. The process is particularly useful in preparing specific rotamers of pharmaceutically useful salts in desired preponderance.
    Type: Grant
    Filed: March 30, 2005
    Date of Patent: May 19, 2009
    Assignee: Schering Corporation
    Inventors: Dinesh Gala, Andrew J. Goodman, Gary Lee, Hongbiao Liao, Martin L. Schwartz, Suhan Tang, David J. S. Tsai, Wenxue Wu
  • Stereoselective alkylation of chiral 2-methyl-4-protected piperazines
    Patent number: 6872826
    Abstract: In an illustrative embodiment, the present invention describes the synthesis of the following compound and similar compounds, in high stereochemical purity by a novel stereoselective alkylation process:
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: March 29, 2005
    Assignee: Schering Corporation
    Inventors: Wenxue Wu, Hongbiao Liao, David J. S. Tsai, David R. Andrews, Dinesh Gala, Gary M. Lee, Martin Lawrence Schwartz, Timothy L. McAllister, Xiaoyong Fu, Donal Maloney, Tiruvettipuram K. Thiruvengadam, Chou-Hang Tann
  • Stereoselective alkylation of chiral 2-methyl-4-protected piperazines
    Publication number: 20030208074
    Abstract: In an illustrative embodiment, the present invention describes the synthesis of the following compound and similar compounds, in high stereochemical purity by a novel stereoselective alkylation process: 1
    Type: Application
    Filed: March 27, 2003
    Publication date: November 6, 2003
    Applicant: Schering Corporation
    Inventors: Wenxue Wu, Hongbiao Liao, David J. S. Tsai, David R. Andrews, Dinesh Gala, Gary M. Lee, Martin Lawrence Schwartz, Timothy L. McAllister, Xiaoyong Fu, Donal Maloney, Tiruvettipuram K. Thiruvengadam, Chou-Hang Tann
  • Synthesis of 4-(piperidyl)(2-pyridyl)methanone-(E)-O-methyloxime and salts
    Publication number: 20030105136
    Abstract: In one embodiment, the present invention describes the synthesis of 4-(piperidyl) (2-pyridyl)methanone-(E)-O-methyloxime dihydrochloride, monohydrochloride and free base, and similar compounds, in high stereochemical purity.
    Type: Application
    Filed: October 11, 2002
    Publication date: June 5, 2003
    Applicant: SCHERING CORPORATION
    Inventors: Wenxue Wu, Hongbiao Liao, David J.S. Tsai
  • Process for the preparation of 17-esters of 9 .alpha., 21-dihalo-pregnane-11 .beta., 17 .alpha.-diol-20-ones
    Patent number: 5886200
    Abstract: The invention provides an improved process for the preparation of 17-esters of 9.alpha.,21 -dihalo-pregnane-11.beta.,17.alpha.-diol-20-ones, and in particular for the preparation of 17-esters of anti-inflammatory steroids according to the following scheme: ##STR1## wherein RCO, R.sup.1, X, Y and the dotted line are as defined in the specification. The novel process is especially suitable for the preparation of Mometasone Furoate.
    Type: Grant
    Filed: June 25, 1997
    Date of Patent: March 23, 1999
    Assignee: Schering Corporation
    Inventors: Daw-Iong Albert Kwok, David J. S. Tsai, Chou-Hong Tann, Xiaoyong Fu