Granted Patent
Utility
US 4,555,569 · App. 06/623,687
Chromogenic quinazolines
Inventors:
Rudolf Zink, Ian J. Fletcher
Patented Case
View Patent ↗
Granted: Nov 26, 1985
Filed: Jun 22, 1984
Inventors
Rudolf Zink
Ian J. Fletcher
Assignee (at issue)
Ciba-Geigy
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.