Granted Patent
Utility
US 5,478,963 · App. 08/184,039
2,3-difluoro-6-nitrobenzonitrile and 2-chloro-5,6-difluorobenzonitrile-(2,3-difluoro-6-chlorobenzonitrile), process for their preparation and their use for the preparation of 2,3,6-trifluorobenzoic acid
Inventors:
Ralf Pfirmann, Theodor Papenfuhs
Patented Case
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Granted: Dec 26, 1995
Filed: Jan 21, 1994
Inventors
Ralf Pfirmann
Theodor Papenfuhs
Assignee (at issue)
Hoechst GmbH
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.