Granted Patent
Utility
US 4,985,554 · App. 07/337,525
Process for the preparation of 3-exomethylene cepham derivatives
Inventors:
Jan Verweij, Jan J. De Koning, Hendrik A. Witkamp
Patented Case
View Patent ↗
Granted: Jan 15, 1991
Filed: Feb 15, 1989
Inventors
Jan Verweij
Jan J. De Koning
Hendrik A. Witkamp
Assignee (at issue)
Gist-Brocades N.V.
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.