Granted Patent
Utility
US 4,535,172 · App. 06/338,008
3(Ether and thioether) 3-(4-dialkylaminophenyl) phthalides
Inventors:
Paul Schmidt, William M. Hung
Patented Case
View Patent ↗
Granted: Aug 13, 1985
Filed: Jan 8, 1982
Inventors
Paul Schmidt
William M. Hung
Assignee (at issue)
Hilton Davis Chemical Co.
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.