The reaction begins with hydrazone
formation (not shown). Hydrazone formation results from the reaction of
the ketone with 2HN-NH2 (hydrazine). This reaction
is like the formation of an oxime with the C=O except that 2HN-NH2
is used instead of 2HN-OH.
MAY REVIEW THE OXIME FORMATION MECHANISM HERE.
The hydrazone is deprotonated to give
a resonance stabilized intermediate.
The anion intermediate is
protonated by the water and then deprotonated.
The deprotonated intermediate then looses N2
gas to form a carbanion. The carbanion is protonated to give the reduction