Patents by Inventor David M. Tschaen

David M. Tschaen 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).

  • Chiral auxilary for stereoselective alkylations
    Patent number: 5856519
    Abstract: This invention relates to a method for the stereoselective synthesis of a 2-aryloxycarboxylic acid using a chiral auxiliary to enhance the stereoselectivity of the alkylation of the .alpha.-halo acid with an aryloxy group.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: January 5, 1999
    Assignee: Merck & Co., Inc.
    Inventors: Paul N. Devine, Richard M. Heid, Jr., David M. Tschaen
  • Compounds formed by an asymmetric conjugate addition reaction
    Patent number: 5849914
    Abstract: This invention relates to a key intermediate in the synthesis of an endothelin antagonist and the synthesis of this key intermediate using an asymmetric conjugate addition reaction.
    Type: Grant
    Filed: August 4, 1997
    Date of Patent: December 15, 1998
    Assignee: Merck & Co., Inc.
    Inventors: Ulf H. Dolling, Lisa F. Frey, Richard D. Tillyer, David M. Tschaen
  • Process of preparing phenyl heterocycles useful as COX-2 inhibitors
    Patent number: 5840924
    Abstract: The invention encompasses a process for making compounds of Formula I useful in the treatment of inflammation and other cyclooxygenase-2 mediated diseases.
    Type: Grant
    Filed: June 16, 1997
    Date of Patent: November 24, 1998
    Assignee: Merck & Co., Inc.
    Inventors: Richard Desmond, Ulf H. Dolling, Lisa F. Frey, Richard D. Tillyer, David M. Tschaen
  • Synthesis of .alpha.-chloro or fluoro ketones
    Patent number: 5786515
    Abstract: A simple, high yielding synthesis of a-chloro ketones is described, involving acylation of Grignard and organolithium reagents with N-methoxy-N-methylchloroacetamide. The efficiency of the process is further enhanced by recycling N,O-dimethylhydroxylamine.
    Type: Grant
    Filed: August 30, 1996
    Date of Patent: July 28, 1998
    Assignee: Merck & Co., Inc.
    Inventors: Ulf H. Dolling, Lisa F. Frey, Richard D. Tillyer, David M. Tschaen
  • Stereoselective process
    Patent number: 5708186
    Abstract: This invention relates to a method for the stereoselective synthesis of a 2-aryloxycarboxylic acid using a chiral auxiliary to enhance the stereoselectivity of the alkylation of the .alpha.-halo acid with an aryloxy group.
    Type: Grant
    Filed: December 6, 1996
    Date of Patent: January 13, 1998
    Inventors: Paul N. Devine, David M. Tschaen, Richard M. Heid, Jr.
  • Process for the preparation of an endothelin antagonist
    Patent number: 5688974
    Abstract: The instant invention relates to a process for the stereoselective synthesis of a compounds of formula I: ##STR1##
    Type: Grant
    Filed: December 6, 1996
    Date of Patent: November 18, 1997
    Assignee: Merck & Co., Inc.
    Inventors: Paul N. Devine, David M. Tschaen
  • Enantioselective synthesis of cyclic amino alcohols
    Patent number: 5574186
    Abstract: There is disclosed a novel process for the enantioselective synthesis of chiral amino alcohols from keto oxime ethers, which are derived from cyclic ketones, via catalytic asymmetric reduction, employing oxazaborolidine-borane complex (OAB-BH.sub.3). In this catalytic reduction process two chiral centers are created in a single step with high levels of stereoselectivity.
    Type: Grant
    Filed: March 8, 1995
    Date of Patent: November 12, 1996
    Assignee: Merck & Co., Inc.
    Inventors: Charles Boudreau, Richard D. Tillyer, David M. Tschaen
  • Process of making spirocycles and analogs thereof
    Patent number: 5484923
    Abstract: The present invention is directed to a process of making spirocycles of general structural formula: ##STR1## where R.sub.1 is selected from the group consisting of CO--C.sub.1-3 alkyl, cyano, carboxy, carboxy C.sub.1-6 alkyl ester, carboxamide, C.sub.1-6 alkyl sulfinyl, C.sub.1-6 alkyl sulfonyl, C.sub.1-6 methanesulfonamide and halogen; R.sub.2 is selected from the group consisting of keto or alcohol, R.sub.3 is cyano, resulting in compounds which are Class III antiarrhythmic.
    Type: Grant
    Filed: May 31, 1994
    Date of Patent: January 16, 1996
    Assignee: Merck & Co., Inc.
    Inventors: Dongwei Cai, Richard Desmond, Yao-Jun Shi, David M. Tschaen, Thomas R. Verhoeven
  • Asymmetric bioreduction of 6-bromo-2-tetralone to (s)-6-bromo-2 tetraol by trichosporon capitatum
    Patent number: 5464762
    Abstract: Stereospecific (S)-6-bromo-2-tetraol is a key intermediate in the chemical synthesis of the chiral drug candidate, MK499, a ventricular arrythmias suppressant. The yeast strain Trichosporon capitatum (MY 1890) was employed for the bioconversion of 6-bromo-2-tetralone to the corresponding alcohol.
    Type: Grant
    Filed: June 24, 1994
    Date of Patent: November 7, 1995
    Assignee: Merck & Co., Inc.
    Inventors: Michel M. Chartrain, Jayanthi Reddy, David M. Tschaen
  • Process for synthesis of FK-506 and tricarbonyl intermediates
    Patent number: 5446158
    Abstract: A process is described for the total synthesis of the macrolide immunosuppressant, FK-506, and important tricarbonyl process intermediates thereof. The tricarbonyl intermediates can be produced by the mild oxidation of 2,3-dihydroxy carboxylate compounds containing olefin moieties.
    Type: Grant
    Filed: October 12, 1990
    Date of Patent: August 29, 1995
    Assignee: Merck & Co., Inc.
    Inventors: Todd K. Jones, Sander G. Mills, David Askin, Robert A. Reamer, Richard Desmond, David M. Tschaen, Ralph P. Volante, Ichiro Shinkai
  • In-situ preparation of diisopinocamphenyl chloroborane
    Patent number: 5292946
    Abstract: The present invention is directed to in-situ preparation of diisopinocamphenylchloroborane, and the use of same in the reduction of prochiral ketones to optically active alcohols such as those of formula B. ##STR1## The compound of Formula B is useful in the production 2,5-diaryltetrahydrofurans useful as PAF antagonists.
    Type: Grant
    Filed: March 23, 1992
    Date of Patent: March 8, 1994
    Assignee: Merck & Co., Inc.
    Inventors: Pamela M. Simpson, David M. Tschaen, Thomas R. Verhoeven
  • Stereoselective synthesis of a chiral cis 3-beta hydrogen (3R) 4-aroyloxy azetidinone
    Patent number: 5145957
    Abstract: A process is described for the stereocontrolled synthesis of (3R,4R)-3-[(1R)-1-hydroxyethyl]-4-benzoyloxyazetidin-2-ones and their derivatives by cycloaddition involving an imine and a ketone, generated from 3(S)-hydroxybutyrate which are useful intermediates in the synthesis of carbapenem antibiotics.
    Type: Grant
    Filed: January 9, 1992
    Date of Patent: September 8, 1992
    Assignee: Merck & Co., Inc.
    Inventors: David M. Tschaen, Joseph E. Lynch, William L. Laswell, Ralph P. Volante, Ichiro Shinkai
  • Deblocking process for allyl esters with regeneratable polymer supported Pd(O)
    Patent number: 5124448
    Abstract: A regeneratable polymer-supported Pd(O) catalytic deblocking process using a regeneratable polymer-supported Pd(O) catalyst in a biphasic system deblocks various allyl-protected ester, carbonates, carbamates and cinnamyl esters.
    Type: Grant
    Filed: November 7, 1990
    Date of Patent: June 23, 1992
    Assignee: Merck & Co., Inc.
    Inventors: David M. Tschaen, F. Edward Roberts, Thomas R. Verhoeven