Patents Assigned to Aktiengesellschaft Wella
  • Patent number: 4900869
    Abstract: A process is disclosed for the production of 4-[ethyl-(2'-hydroxyethyl)-amino]-1-[(2'-hydroxyethyl)-amino]-2-nitrobenze ne, by means of a two-stage technique proceeding from the reaction product of 1,4-diamino-2-nitrobenzene with chloroformic acid chloroethyl ester, or by means of a multiple-stage technique which is based upon an improved process for the production of the pre-stage 4-ethylamino-1-[(2'-hydroxyethyl)-amino]-2-nitrobenzene through sulfuric acid splitting off of 4-(N-ethylarylsulfonamido)-1-[(2'-hydroxyethyl)-amino]-2-nitrobenzene.
    Type: Grant
    Filed: November 6, 1987
    Date of Patent: February 13, 1990
    Assignee: Aktiengesellschaft Wella
    Inventors: Thomas Clausen, Isolde Lowe