Figure 6. Recyclability and reusability of the Cu-B nanocatalyst for the Ullmann amination.

Reaction conditions: 4-iodoanisole (1a, 1 mmol, 234 mg), methylamine (2a, 40 wt % aqueous solution, 2.5 mL, 28.9 mmol), Cs₂CO₃ (2 mmol, 651 mg), Cu-B (20 mg, 1.35 mol% for Cu), temperature 110°C, and time 3 h.