Application of Bertagnini's Salts in a Mechanochemical Approach Toward Aza-Heterocycles and Reductive Aminations via Imine Formation

Our research has demonstrated that mechanochemical activation is more effective with solid reagents. We have showcased the practicality of Bertagnini's salts, also called aldehyde-bisulfite adducts, which are crystalline, simplifying preparation and storage. These salts are stable substitutes for liquid aldehydes and ketones that have been employed in reductive amination, synthesizing aza-heterocycles and hydrazones within mechanochemistry. The technique‘s effectiveness broadens the substrate scopes, simplifies purification, reduces reaction times, and yields the desired products ranging from 38–91%. Additionally, the thermal stability of the bisulfite adducts has been confirmed through TGA (Thermogravimetric analysis) analysis.