Facile Biphasic Deprotection of Aldehyde Dimethylhydrazones with Aqueous Hydrochloric Acid

Deprotection of aldehyde dimethylhydrazones was accomplished by stirring a biphasic mixture of the aldehyde dimethylhydrazone, 1M hydrochloric acid, and petroleum ether at room temperature for three to seven hours. The method works with α,β-unsaturated- and diene-aldehyde dimethylhydrazones, which are often difficult compounds to deprotect. Isolated yields ranged from 85% to 97%.