2,2'-Bithiophene → 5-Iodo-2,2'-bithiophene

Participants

Reaction Steps

33.2 g of 2,2'-bithiophene was dissolved in 50 ml of ethanol and I2 /EtOH (20.3 g/220 ml) was added. Then HIO3 /H2O (12 g/20 ml) were added slowly during 2 hours with stirring. The mixture was stirred for further 3 hours and the ethanol was evaporated. The residue was extracted with dichloromethane and dried over anhydrous magnesium sulfate. After the solvent was removed, the crude product was vacuum distilled to give 5-iodo-2,2'-bithiophene 36.8 g (105°-110° C./0.1 mm-Hg). The yield is 65-70%. The residue was purified by silica column chromatography and yielded 5.36 g of 5,5'-diiodo-2,2'-bithiophene (6.4%) with melting point of 170° C.

Provenance & Evidence