Substituted derivatives of 20,21-dinoreburnamenine, their preparation process and the new intermediates thus obtained, their use as medicaments and the pharmaceutical compositions containing them

Granted: Jul 26, 1994 Filed: Jan 19, 1993

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.