4a, 5a, 8a, 8b--tetrahydro-6H-ptrrolo [3,4':4,5]furo(3,2-b) pyridine-6,8[7H]-dione derivatives for use in controlling endoparasites and a method of producing said derivatives

Granted: Aug 29, 2000 Filed: Apr 15, 1998

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.