Pyridazinones from maleic hydrazide: a new substrate for the Mitsunobu reaction.

The article discusses a study on a two-step route, which is Mitsunobu followed by Schiff base reactions, to asymmetrically substituted pyridazinones from maleic hydrazide with 2-, 3-, or 4-pyridinecarboxaldehyde. Highlights include the reaction of maleic hydrazide with ethanolamine under Mitsunobu conditions, the use of ethanolamine when performing the Mitsunobu step, and hydrogen bonded dimers and close stacking of pyridazinone moieties.