Potassium Iodide → 2-Amino-5-chloro-3-iodopyridine

Participants

Reaction Conditions

Reaction Steps

A stirred solution of 5-chloro-pyridin-2-ylamine (51.4 g, 0.40 mol) in 2M sulfuric acid (700 mL) was treated portionwise with potassium iodate (43.7 g, 0.2 mol) and the mixture heated to 100° C. A solution of potassium iodide (36.5 g, 0.55 mol) in water (100 mL) was added dropwise over ca. 1 hour. The mixture was allowed to stir for a further 30 minutes then cooled to ambient temperature. The pH of the aqueous phase was adjusted to 8-9 and the mixture extracted with ethyl acetate (×3). The combined organic layer was washed with aqueous sodium thiosulfate solution, water and brine, dried (Na2SO4), filtered and evaporated to afford the title compound as a tan solid (86.3 g, 84%). LCMS (Method B): RT=3.76 min, M+H+=255/257. 1H NMR (400 MHz, CDCl3): 7.98 (d, J=2.3 Hz, 1H), 7.84 (d, J=2.3 Hz, 1H), 5.03 (s, 2H).

Provenance & Evidence