An
environmentally-friendly method for the clean preparation of
various quinolin-2-yl substituted ureas in water under mild and toxic
reagent-, base-, and organic solvent-free conditions was established.
In the large-scale synthesis, the products could be rapidly collected
via simple filtration and washing with ethanol. The usage of readily
available raw materials, 100% atom economy, high yield, and excellent
regioselectivity enhanced the practicability of this protocol.