Iodine → 2-Iodo-6-methoxynaphthalene

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (2.5 M in hexanes, 92 mL, 230 mmol) is added via dropping funnel to a solution of 2-bromo-6-methoxy-naphthalene (49.5 g, 209 mmol) in anhydrous THF (2 L) at −75° C. at such a rate that the temperature is kept below −70° C. (over 45 min). The resulting yellow solution is stirred for 15 min at −75° C. A solution of iodine (58.3 g, 230 mmol) in anhydrous THF (100 mL) is added via a fresh dropping funnel until the red iodine colour persists (addition over 45 min, max. temp. −68° C.). The mixture is warmed to rt. and water (1.3 L) is added. The mixture is extracted with dichloromethane (2 L) with brine (500 mL) being added to aid the separation. The aqueous fraction is back-extracted with dichloromethane (1 L). The combined organic fractions are reduced in vacuo to approx. 1 L, washed with saturated aqueous sodium metabisulphite (100 mL), then brine (200 mL), dried (Na2SO4), filtered and solvent removed in vacuo. The crude residue is recrystalised from IMS (1.9 l) washing with ice-cold IMS (2×150 mL) and dried in a vacuum oven at 70, ° C. to give a light cream crystalline solid. 46.45 g, 78%.

Provenance & Evidence