Patents by Inventor Helmut Karn

Helmut Karn 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: 5008398
    Abstract: A process for the preparation of imidazoles which are substituted with p-nitrophenyl in the 2- and/or 4- and/or 5-position and may carry additional substituents, by reacting imidazoles which are substituted by phenyl in the 2- and/or 4- and/or 5-position and may carry additional substituents with mixtures of sulfuric acid and nitric acid, wherein the reaction is carried out in the presence of urea.
    Type: Grant
    Filed: October 2, 1989
    Date of Patent: April 16, 1991
    Assignee: BASF Aktiengesellschaft
    Inventors: Hermann Koehler, Klaus Ebel, Helmut Karn, Christof Taubitz
  • Patent number: 4866183
    Abstract: Hexaarylbisimidazoles I ##STR1## where Ar.sup.1, Ar.sup.2 and Ar.sup.3 are each aryl, of which Ar.sup.2 and Ar.sup.3 can be linked to form an anellated ring system, are prepared by oxidizing the corresponding triarylimidazoles II in an aqueous/organic two-phase system in the presence of active amounts of an onium salt III.
    Type: Grant
    Filed: June 9, 1987
    Date of Patent: September 12, 1989
    Assignee: BASF Aktiengesellschaft
    Inventors: Uwe Kempe, Toni Dockner, Helmut Karn, Thomas Bluemel, Reinhold J. Leyrer, Thomas Loerzer
  • Patent number: 4864030
    Abstract: Process for the preparation of 1-alkylimidazoles of the general formula (I) ##STR1## where R.sup.1 is alkyl, R.sup.2 and R.sup.3 are hydrogen, alkyl, aryl, arylalkyl, or alkylaryl, R.sup.4 is carboxy, alkoxycarbonyl R.sup.5 OCC--, carbamoyl, or cyano, and R.sup.5 is an alkyl of from 1 to 8 carbon atoms--by the reaction of imidazoles of the general formula (II) ##STR2## with dialkyl sulfates of the general formula (III)(R.sup.1 O).sub.2 SO.sub.2 (III)at elevated temperatures in the presence of a carboxylic acid or anhydride or of both acid and anhydride.
    Type: Grant
    Filed: August 30, 1988
    Date of Patent: September 5, 1989
    Assignee: BASF Aktiengesellschaft
    Inventors: Hermann Koehler, Toni Dockner, Helmut Karn
  • Patent number: 4278801
    Abstract: A process for the manufacture of 5-hydroxymethylimidazoles by reaction of an imidazole with formaldehyde or an oligomer of formaldehyde in aqueous hydrochloric acid solution containing from 5 to 18% by weight of hydrogen chloride, at from 80.degree. to 160.degree. C., if desired in a closed system under pressure, followed by isolation in the form of its hydrochloride of the 5-hydroxymethylimidazole obtained.
    Type: Grant
    Filed: February 8, 1980
    Date of Patent: July 14, 1981
    Assignee: BASF Aktiengesellschaft
    Inventors: Uwe Kempe, Toni Dockner, Anton Frank, Helmut Karn
  • Patent number: 4242517
    Abstract: 1-Hydroxymethylimidazoles which are unsubstituted or alkyl-substituted in the 2-position, their manufacture and their use as chemical intermediates, e.g. for other imidazole derivatives or for the drug cimetidine.
    Type: Grant
    Filed: August 8, 1979
    Date of Patent: December 30, 1980
    Assignee: BASF Aktiengesellschaft
    Inventors: Toni Dockner, Anton Frank, Uwe Kempe, Matthias Wetzler, Helmut Karn
  • Patent number: 4239895
    Abstract: 1-Hydroxymethylimidazoles which are unsubstituted or alkyl-substituted in the 2-position, their manufacture and their use as chemical intermediates, e.g. for other imidazole derivatives or for the drug cimetidine.
    Type: Grant
    Filed: August 8, 1979
    Date of Patent: December 16, 1980
    Assignee: BASF Aktiengesellschaft
    Inventors: Toni Dockner, Anton Frank, Uwe Kempe, Matthias Wetzler, Helmut Karn
  • Patent number: 4021442
    Abstract: 1-Alkyl-5-nitroimidazoles are prepared by reacting a 5-nitroimidazole with an alkylating agent in the presence of an aliphatic carboxylic acid. The products are intermediates for the production of dyes, textiles auxiliaries and insecticides.
    Type: Grant
    Filed: March 11, 1975
    Date of Patent: May 3, 1977
    Assignee: BASF Aktiengesellschaft
    Inventors: Anton Frank, Helmut Karn, Toni Dockner