Granted Patent
Utility
US 4,952,706 · App. 07/417,089
Derivatives of 2-pyrrolidone-5-carboxylic acid and method of obtaining them
Inventors:
Hans-Peter Krimmer, Karlheinz Drauz
Patented Case
View Patent ↗
Granted: Aug 28, 1990
Filed: Oct 4, 1989
Inventors
Hans-Peter Krimmer
Karlheinz Drauz
Assignee (at issue)
Degussa AG
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.