Solvent-free synthesis of hydrazones and their subsequent N-alkylation in a Ball-mill

A large variety of Boc-, Bz-, Ts-, and Fmoc- protected hydrazones were prepared via condensation of an equimolar amount of carbonyl-compound and the corresponding hydrazine using a ball-mill. Hydrazones were always obtained in a quantitative yield and no solvents were used at any step. In a second step, we realized the first solvent-free N-allylation and N-benzylation of these hydrazones.