Acetonitrile → 3-Iodoimidazo[1,2-a]pyridine

Participants

Reaction Steps

A solution of 11.61 g (98.27 mmol) of imidazopyridine in 100 mL of acetonitrile was placed in a 250 mL three-neck round-bottom flask equipped with a magnetic stirrer, thermocouple, nitrogen bleed, and cooling ice bath. A total of 24.32 g (108.1 mmol, 1.1 eq.) of solid N-iodosuccinimide was added portion-wise to the flask at 0° C., and the resulting yellow suspension was allowed to warm to room temperature overnight. The solvent was removed on rotavap to give the dark solid (39.2 g). This residue was re-dissolved in 0.5 L of dichloromethane and washed with 10% KOH (2×250 mL). The organic phase was separated, washed with water (200 mL), and dried over Na2SO4. The solvent was removed on rotavap, and the remaining dark material was re-crystallized from boiling ethyl acetate upon the addition of hexane. The precipitated solid was filtered, washed with 40 mL of hexane, and dried under nitrogen flow until constant weight. The yield was 20.8 g (86%) of white solid with Rf=0.42 (in EtOAc/hexane=1:1).

Provenance & Evidence