Patents by Inventor George S. K. Wong

George S. K. Wong 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).

  • Patent number: 5870483
    Abstract: A sound-insulating cap is designed for conventional microphones without EMI protection. In an environment where EMI is likely to affect the performance of a conventional microphone, the cap is used to eliminate a substantial part of the acoustic noise and thus assess whether EMI is present during the measurements using the microphone. The cap has a member snugly fitting over the receptor of a microphone, the member made of a number of layers of acoustically different materials. Venting is provided to prevent a damage to the membrane of the microphone during the installation and removal of the cap.
    Type: Grant
    Filed: February 24, 1997
    Date of Patent: February 9, 1999
    Assignee: National Research Council of Canada
    Inventors: George S. K. Wong, Noland L. Lewis
  • Patent number: 5521320
    Abstract: This invention relates to a process of obtaining optically pure enantiomers of an alkylated oxindole selected from ##STR1## where R is methyl, ethyl or benzyl.
    Type: Grant
    Filed: May 27, 1993
    Date of Patent: May 28, 1996
    Assignee: Hoechst-Roussel Pharmaceuticals Incorporated
    Inventors: Thomas B. K. Lee, George S. K. Wong
  • Patent number: 5455354
    Abstract: This invention relates to a process for the preparation of a product of the formula ##STR1## wherein R, R.sup.1, R.sup.2, X and m are defined within which process comprises(a) contacting a compound of Formula II ##STR2## wherein R.sup.3 is loweralkyl, with a reagent selective from the group consisting of aluminum chloride, hydrobromic acid and boron tribromide followed by tartaric acid to afford a compound of Formula III ##STR3## wherein R, X and m are as defined above; (b) contacting the reaction mixture containing compound of Formula IV ##STR4## wherein R.sup.4 is hydrogen or loweralkyl in the presence of a carboxylic acid of the formulaR.sup.5 COOHwherein R.sup.5 is loweralkyl to afford a compound of formula V ##STR5## wherein R, R.sup.4, X and m are as above; contacting the reaction mixture containing the compound of Formula V obtained in step(b) with a compound of the formulaR.sup.1 R.sup.2 NHwherein R.sup.1 and R.sup.2 are as above; and isolating the product of Formula I.
    Type: Grant
    Filed: February 17, 1994
    Date of Patent: October 3, 1995
    Assignee: Hoechst-Roussel Pharmaceuticals Incorporated
    Inventors: George S. K. Wong, Thomas B. K. Lee, Franz J. Weiberth
  • Patent number: 5387695
    Abstract: A process for chemically resolving a mixture of enantiomers of primary amines, such as enantiomers of 1,3-dimethyl-5-methoxyoxindolylethylamine, provides one of the enantiomers in the form of a tartaric acid salt. In carrying out the process, an enantiomeric mixture is contacted with a chiral acid in an amount sufficient to preferentially precipitate a salt of the chiral acid and one of the enantiomers. The resulting precipitate can then be recovered. The chiral acid is selected from the group consisting of dibenzoyl-D-tartaric acid, dibenzoyl-L-tartaric acid, ditoluoyl-D-tartaric acid, and ditoluoyl-L-tartaric acid. The precipitates can be used in the synthesis of stereospecific forms of physostigmine.
    Type: Grant
    Filed: February 17, 1993
    Date of Patent: February 7, 1995
    Assignee: Hoechst-Roussel Pharmaceuticals, Inc.
    Inventors: Thomas B. K. Lee, George S. K. Wong
  • Patent number: 5302721
    Abstract: This application relates to a new process for the preparation of a product of the formula ##STR1## wherein R is loweralkyl;R.sup.1 is hydrogen, loweralkyl, lowercycloalkyl, lowercycloalkylloweralkyl, lowerbicycloalkyl, aryl or arylloweralkyl;R.sup.2 is loweralkyl, lowercycloalkyl, lowercycloalkylloweralkyl, lowerbicycloalkyl, aryl or arylloweralkyl; orR.sup.1 and R.sup.2 taken together with the nitrogen atom to which they are attached from a 3,4-dihydro-2H(1H)-isoquinoline group;X is loweralkyl, loweralkoxy, halogen or trifluoromethyl; andm is 0, 1 or 2;which process comprises(a) contacting a compound of formula II ##STR2## wherein R, X and m are as defined above and R.sup.3 is loweralkyl, with aluminum chloride followed by tartaric acidto afford a compound of formula III ##STR3## wherein R, X and m are as defined above; (b) contacting the reaction mixture containing the compound of Formula III either(1) with an isocyanate of the formula R.sup.1 NCO and obtaining a product of the formula I wherein R.sup.
    Type: Grant
    Filed: July 21, 1992
    Date of Patent: April 12, 1994
    Assignee: Hoechst-Roussel Pharmaceuticals Incorporated
    Inventors: George S. K. Wong, Thomas B. K. Lee, Franz J. Weiberth
  • Patent number: 5274117
    Abstract: A process for the stereoselective synthesis of [R]- and [S]-2,3-dihydro-1,3-dimethyl-2-oxo-1H-indole-3-acetonitriles comprises reacting racemic and 5-alkoxy-substituted (.+-.)-1,3-dimethyloxindoles with a halogenated acetonitrile in the presence of a substituted N-benzyl cinchoninium, quinidinium, cinchonidinium, or quininium catalyst. The resulting alkylated oxindoles can be converted to primary amines by catalytic reduction in the presence of hydrogen gas. One of the primary amines, such as enantiomers of 3-(2-aminoethyl)-1,3-dihydro-1,3-dimethyl-5-methoxy-2H-indol-2-one, can be enriched by contact with a chiral tartaric acid in an amount sufficient to preferentially precipitate a salt of the chiral acid and one of the enantiomers. The product can be used in the synthesis of stereospecific forms of physostigmine and related compounds having pharmaceutical activity.
    Type: Grant
    Filed: February 12, 1992
    Date of Patent: December 28, 1993
    Assignee: Hoechst-Roussel Pharmaceuticals, Inc.
    Inventors: Thomas B. K. Lee, George S. K. Wong
  • Patent number: 5053513
    Abstract: A method of reducing a carbonyl containing acridine of the formula ##STR1## where n is 1, 2 or 3; X is hydrogen, loweralkyl, loweralkoxy, halogen, hydroxy, trifluoromethyl, or NR.sub.3 R.sub.4 where R.sub.3 and R.sub.4 are independently hydrogen or loweralkyl; R is hydrogen or loweralkyl and R.sub.1 is hydrogen, loweralkyl, diloweralkylaminoloweralkyl, arylloweralkyl, diarylloweralkyl, furylloweralkyl, thienylloweralkyl, oxygen-bridged arylloweralkyl, oxygen-bridged diarylloweralkyl, oxygen-bridged furylloweralkyl or oxygen-bridged thienylloweralkyl, is disclosed.
    Type: Grant
    Filed: March 29, 1990
    Date of Patent: October 1, 1991
    Assignee: Hoechst-Roussel Pharmaceuticals Incorporated
    Inventors: Thomas B. K. Lee, George E. Lee, George S. K. Wong, Donna M. Borek, Keith E. Goehring
  • Patent number: 4988813
    Abstract: 2-Amino-4-hydroxy-6-[2-(4-carboxyphenyl)alk-1-en-1-yl]pyrido[2,3,-d]pyrimid ines and 2-amino-4-hydroxy-6-[2-(4-carboxyphenyl)alk-1-yn-1-yl]pyrido[2,3-d]pyrimid ines are prepared through through the reaction of a haloaromatic compound and an unsaturated compound in the presence of a palladium catalyst. The products are chemical intermediates for the preparation of antineoplastic agents.A typical embodiment is the reaction of a protected 2-amino-4-hydroxy-6-ethynylpyrido[2,3-d]pyrimidine and an ester of 4-iodobenzoic acid.
    Type: Grant
    Filed: August 8, 1988
    Date of Patent: January 29, 1991
    Assignee: The Trustees of Princeton University
    Inventors: Edward C. Taylor, George S. K. Wong
  • Patent number: 4902796
    Abstract: 2-Amino-4-hydroxy-6-[2-(4-carboxyphenyl)alk-1-en-1-yl]pyrido[2,3,-d]pyrimid ines and 2-amino-4-hydroxy-6-[2-(4-carboxyphenyl)alk-1-yn-1-yl]pyrido[2,3-d]pyrimid ines are prepared through the reaction of a halo-aromatic compound and an unsaturated compound in the prosence of a palladium catalyst. The products are chemical intermediates for the preparation of antineo-plastic agents.A typical embodiment is the reaction of a protected 2-amino-4-hydroxy-6-ethynylpyrido[2,3-d]pyrimidine and an ester of 4-iodobenzoic acid.
    Type: Grant
    Filed: August 8, 1988
    Date of Patent: February 20, 1990
    Assignee: The Trustees of Princeton University
    Inventors: Edward C. Taylor, George S. K. Wong
  • Patent number: 4877697
    Abstract: A liquid crystal display having display filter elements in registration with display electrodes. The filters are produced using color proofing films which are imaged to produce a regular pattern of dots. Filter elements are illuminated by electrodes selection to produce changeable images.
    Type: Grant
    Filed: May 26, 1988
    Date of Patent: October 31, 1989
    Assignees: Hoechst Aktiengesellschaft, Hiechst Celanese Corporation
    Inventors: Hansjoerg W. Vollmann, George S. K. Wong, Dennis Bellville
  • Patent number: 4818819
    Abstract: 2-Amino-4-hydroxy-6-[2-(4-carboxyphenyl)alk-1-en-1-yl]pyrido[2,3,-d]pyrimid ines and 2-amino-4-hydroxy-6-[2-(4-carboxyphenyl)alk-1-yn-1-yl]pyrido[2,3-d]pyrimid ines are prepared through the reaction of a haloaromatic compound and an unsaturated compound in the presence of a palladium catalyst. The products are chemical intermediates for the preparation of antineoplastic agents.A typical embodiment is the reaction of a protected 2-amino-4-hydroxy-6-ethynylpyrido[2,3-d]pyrimidine and an ester of 4-iodobenzoic acid.
    Type: Grant
    Filed: October 20, 1986
    Date of Patent: April 4, 1989
    Assignee: The Trustees of Princeton University
    Inventors: Edward C. Taylor, George S. K. Wong
  • Patent number: 4145661
    Abstract: The precision measuring amplifier includes one or more amplifiers, a number of fixed attenuators, a RMS detector and a logarithmic converter for converting the output of the RMS detector to a logarithmic value. A number of fixed voltage sources each providing a voltage precisely related to the attenuation of a corresponding attenuator, are selectively coupled to a summing amplifier to which the logarithmic converter output is also connected. The number of attenuators connected either manually or automatically into amplifier apparatus at one time is dependent on the input signal level, and for every attenuator connected into the amplifier apparatus, a voltage source is connected to the summing amplifier to provide an output signal proportional to the logarithm of the RMS value of the input signal.
    Type: Grant
    Filed: December 28, 1977
    Date of Patent: March 20, 1979
    Assignee: Canadian Patents and Development Limited
    Inventor: George S. K. Wong