Patents by Inventor Paul J. Schmidt

Paul J. Schmidt 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).

  • 3-[4-(Disubstituted-amino)phenyl]-3-(diphenylamino)phthalides
    Patent number: 4187223
    Abstract: 3-[4-(Disubstituted-amino)phenyl] or (9-julolidinyl)-3-(diphenylamino)phthalides useful as color formers in pressure-sensitive and thermal marking systems are prepared by reaction of 2-[4-(disubstituted-amino)benzoyl] or (9-julolidinyl-carbonyl)benzoic acids with diphenylamines.
    Type: Grant
    Filed: September 18, 1978
    Date of Patent: February 5, 1980
    Assignee: Sterling Drug Inc.
    Inventors: Paul J. Schmidt, William M. Hung
  • Carbazole containing phthalides
    Patent number: 4182714
    Abstract: 3-Heteroaryl-3-(diphenylamino)phthalides useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems are prepared by reacting 2-(heteroarylcarbonyl)-benzoic acids with diphenylamines.
    Type: Grant
    Filed: August 4, 1977
    Date of Patent: January 8, 1980
    Assignee: Sterling Drug Inc.
    Inventors: Paul J. Schmidt, William M. Hung
  • 3-(9-Julolidinyl)-3-(diphenylamino)phthalides
    Patent number: 4168378
    Abstract: 3-[4-Disubstituted-amino)phenyl] or (9-julolidinyl)-3-(diphenylamino)phthalides useful as color formers in pressure-sensitive and thermal marking systems are prepared by reaction of 2-[4-disubstituted-amino)benzoyl] or (9-julolidinyl-carbonyl)benzoic acids with diphenylamines.
    Type: Grant
    Filed: August 4, 1977
    Date of Patent: September 18, 1979
    Assignee: Sterling Drug Inc.
    Inventors: Paul J. Schmidt, William M. Hung
  • Benzoylbenzoic acids
    Patent number: 4096176
    Abstract: Substituted 3,3-diphenylphthalides, useful as color precursors, particularly in the art of pressure-sensitive duplicating systems, are prepared by condensing substituted 2-benzoylbenzoic acids with substituted anilines.
    Type: Grant
    Filed: December 12, 1972
    Date of Patent: June 20, 1978
    Assignee: Sterling Drug Inc.
    Inventors: Nathan N. Crounse, Paul J. Schmidt
  • Tri- or tetrasubstituted diphenylphthalides
    Patent number: 4094877
    Abstract: Substituted 3,3-diphenylphthalides, useful as color precursors, particularly in the art of pressure-sensitive duplicating systems and heat-sensitive marking systems, are prepared by condensing substituted 2-benzoylbenzoic acids with substituted anilines.
    Type: Grant
    Filed: November 10, 1976
    Date of Patent: June 13, 1978
    Assignee: Sterling Drug Inc.
    Inventors: Nathan N. Crounse, Paul J. Schmidt
  • Phenyljulolidinylphthalides
    Patent number: 4032527
    Abstract: Substituted 3,3-diphenylphthalides, useful as color precursors, particularly in the art of pressure-sensitive duplicating systems, are prepared by condensing substituted 2-benzoylbenzoic acids with substituted anilines.
    Type: Grant
    Filed: November 27, 1974
    Date of Patent: June 28, 1977
    Assignee: Sterling Drug Inc.
    Inventors: Nathan N. Crounse, Paul J. Schmidt