Granted Patent
Utility
US 4,831,265 · App. 07/033,864
Method of producing quinone derivatives
Inventors:
Masazumi Watanabe, Isuke Imada
Patented Case
View Patent ↗
Granted: May 16, 1989
Filed: Apr 3, 1987
Inventors
Masazumi Watanabe
Isuke Imada
Assignee (at issue)
Takeda Chemical Industries Ltd.
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.