Granted Patent
Utility
US 4,921,971 · App. 07/258,739
Method of preparing alkaline earth metal salts of 2-pyrrolidone-5-carboxylic acid
Inventors:
Hans-Peter Krimmer, Karlheinz Drauz, Silvia Werner
Patented Case
View Patent ↗
Granted: May 1, 1990
Filed: Oct 17, 1988
Inventors
Hans-Peter Krimmer
Karlheinz Drauz
Silvia Werner
Assignee (at issue)
Dequssa 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.