Halogenation reactions in biodegradable solvent: Efficient bromination of substituted 1-aminoanthra-9,10-quinone in deep eutectic solvent (choline chloride : urea)

A simple ammonium deep eutectic solvent was used as a dual catalyst and environmentally benign reaction medium for the bromination of 1-aminoanthra-9,10-quinone, eliminating the need for volatile organic solvents and concentrated acids like H2SO4 as solvents or catalysts. This simple ammonium deep eutectic solvent, easily synthesized from choline chloride and urea, is relatively inexpensive and biodegradable, making it applicable for industrial applications. The deep eutectic solvent was easily separated and reused without loss of activity, and thus provides a good alternative for industrial bromination of 1-aminoanthra-9,10-quinone.