Patents Examined by R. W. Romsuer
  • Process for the preparation of derivatives of 3-(4-hydroxy-anilino)carbazole
    Patent number: 4320060
    Abstract: The process for the preparation of a 3-(4-hydroxyanilino)carbazole of the formula ##STR1## wherein R is hydrogen, alkyl having 1 to 8 carbon atoms or halogenoalkyl having 1 to 8 carbon atoms, comprising reacting a 3-aminocarbazole of the formula ##STR2## with p-hydroquinone or p-aminophenol or a mixture of p-hydroquinone and p-aminophenol in at least stoichiometric amounts by heating to a temperature of 150.degree. to 300.degree. C. with exclusion of oxygen.
    Type: Grant
    Filed: December 31, 1979
    Date of Patent: March 16, 1982
    Assignee: Cassella Aktiengesellschaft
    Inventors: Steffen Piesch, Friedrich Engelhardt, Herbert Wille, Wolf Weidemuller, Artur Meyer