Reduction of Different Electron‐Poor N ‐Heteroarylhydrazines in Strong Basic Conditions

The first application of the Wolff–Kishner reduction methodology to electron‐poor heteroaromatic compounds is reported. Hydrazino‐containing heterocycles with hydrazone‐type tautomery have been reduced under basic conditions. This novel chemistry was successfully applied to mono‐dehalogenate a number of electron‐poor heterocycles in a regioselective manner. According to the experimental results, this reductive process is a base‐catalyzed reaction that takes only place in the presence of air, probably through an oxygen‐assisted mechanism. As consequence of the specific features of this kind of hydrazone/enehydrazine tautomers, the overall outcome of the process is the synthesis of a Shapiro‐type reduction product by simply using a milder version of the Huang–Minlon methodology.