Iodine → 5-Iodo-2,2'-bithiophene

Participants

Reaction Steps

To a solution of 2,2'-bithiophene (33.2 g) in ethanol (50 ml) was added iodine (20.3 g) in ethanol (200 ml). Then iodine (V) oxide (6.7 g) in ethanol (30 ml) was added dropwisely. The reaction mixture was further stirred at room temperature for 5 hours. Ethanol was removed and the residue was dissolved in dichloromethane. The solution was washed with sodium bicarbonate aqueous solution (10%, 150 ml×2) then water (200 ml×2). Dried over anhydrous magnesium sulfate and concentrated to give crude products. Distilled under vacuum (105°-110° C./0.1 mm Hg) to give 5-iodo-2,2'-bithiophene (36.8 g, 63%). The residue was then separated by silica gel chromatography eluted with n-hexane to give 5,5'-diiodo-2,2'-bithiophene (5.36 g, 6.4%), melting point 170° C.

Provenance & Evidence