Methods for selectively protecting one of the degenerate nitrogen atoms of the cyclic urea derivatives 1, 3-dihydro-W-benzimidazol-2-one (6a), 1, 3-dihydro-W-imidazo [4, 5-b] pyridin- 2-one (ll), 1, 3-dihydro-W-imidazo [4, 5-blquinolin-2-ones (20), 1, 3-dihydro-W-imidazo~ 4, 5clpyridin-2-one (22), and 1, 3-dihydro-4-phenyl-W-imidazol-2-one (27) were developed. Heating these cyclic ureas with ethyl 2-pyridyl carbonate in the presence of a base in ...