Iodine → 7-iodo-2-(3,4,5-trimethoxy-phenyl)-5H-pyrrolo[2,3-b]pyrazine

Participants

Reaction Steps

To a 0° C. mixture of 2-(3,4,5-trimethoxy-phenyl)-5H-pyrrolo[2,3-b]pyrazine (2.4 g, 8.4 mmol) in dimethylformamide (30 ml) was added KOH (2 g, 36 mmol). After 20 min, iodine (3.2 g, 13 mmol) was added portionwise over 10 min and the reaction mixture was stirred for 4 h and poured into 0° C. saturated aqueous sodium thiosulfate (˜300 mL). Ice cold water (˜100 mL) was added and the resultant precipitate was collected, washed with water and dried in vacuo at 60° C. to afford 3.1 g (89%) of 7-iodo-2-(3,4,5-trimethoxy-phenyl)-5H-pyrrolo[2,3-b]pyrazine as a brown solid. MP 230-232° C., M+H=412.

Provenance & Evidence