Eco-Friendly Amide Synthesis Using a Metal and Halogen-Free Deep Eutectic Solvent.

A halogen- and metal-free deep eutectic solvent (DES) consisting of choline hydroxide (ChOH) and urea (1:2) was employed as a green, reusable, and cost-effective medium for the one-pot synthesis of amide derivatives from aldehydes and hydroxylamines. The DES served simultaneously as solvent and catalyst, enabling the efficient formation of a wide variety of amides. The protocol afforded biologically and medicinally relevant compounds, including nicotinamide and bebenil, in excellent yields under mild conditions.