Potassium Iodide → 1-(4-chlorobenzyl)-3-hydroxypyridin-2(1H)-one

Participants

Reaction Steps

to a nitrogen purged 1-L round bottom flask equipped with a mechanical stirrer, upright condenser, and thermometer was charged 3-hydroxypyridin-2(1H)-one [2,3-dihydroxypyridine] (40.0 g, 0.36 mol, 1 equiv.) [CAS No. 16867-04-2], ammonium sulfate (2.4 g, 0.02 mol, 0.05 equiv.) and acetonitrile (200 mL, 5 parts v/w). The resulting suspension was stirred at room temperature. Hexamethyldisilazane (116.2 g, 0.72 mol, 2 equiv.) is added dropwise. The resulting suspension was heated to reflux for 4 hours. The solution was then cooled to room temperature followed by the addition of a solution of 4-chlorobenzyl chloride (63.8 g, 0.4 mol, 1.1 equiv.) in acetonitrile (40 mL, 1 part v/w). Potassium iodide (59.8 g, 0.36 mol, 1 equiv.) is then added. The solution was then brought to reflux for 16 hours. The solution was cooled to 5° C. and water (240 mL) was slowly added over 15 minutes. The reaction mixture was allowed to warm to room temperature and stirring was continued for 2 hours. The solution was filtered under vacuum and rinsed with water (360 mL). The filter cake is then washed with methyl tert-butyl ether (360 mL). The resulting green-brown solid is vacuum dried to afford 63.5 g (86.2%) of the desired product. 1H NMR (DMSO-d6) δ ppm 7.4 (d, 2H), 7.3 (d, 1H), 7.2 (d, 2H), 6.7 (d, 1H), 6.1 (t, 1H), and 5.1 (s, 2H).

Provenance & Evidence