Selective Fluorination of 4-Substituted 2-Aminopyridines and Pyridin-2(1 H)-ones in Aqueous Solution.

Fluorination of 2-aminopyridines and pyridin-2(1 H)-ones in the presence of Selectfluor, water, and chloroform under mild conditions has been realized. This method gives fluorinated pyridines in good to high yields with high regioselectivities. The electron-deficient pyridine system is activated by an amino or hydroxyl group at C2. The regioselectivity of the fluorination reaction is strongly dependent upon the substituent pattern in the 2-aminopyridine or pyridin-2(1 H)-one. The transformation of the 3-fluoro-substituted pyridine derivative into fluorinated zolimidine was achieved as well.