Process for the preparation of pyridine-2-3-dicarboxylic acid derivatives, and novel 1-amino-1,4-dihydropyridine-2-3-diarboxylic acid derivatives

Granted: May 31, 1988 Filed: May 3, 1985

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.