Granted Patent
Utility
US 4,618,714 · App. 06/490,546
Process for preparation of 3,3'- or 3,4'-diaminobenzophenones
Inventors:
Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe, Saburo Kawashima, Akihiro Yamaguchi
Patented Case
View Patent ↗
Granted: Oct 21, 1986
Filed: May 2, 1983
Inventors
Keizaburo Yamaguchi
Kenichi Sugimoto
Yoshimitsu Tanabe
Saburo Kawashima
Akihiro Yamaguchi
Assignee (at issue)
Mitsui Toatsu Chemicals, Incorporated
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.