Iodine → 7-Bromo-3-methyl-1H-indole

Participants

Reaction Conditions

Reaction Steps

Magnesium turnings (1.45 g) in dry THF (10 ml) were stirred at room temperature under nitrogen and an iodine crystal added, followed by a few milliliters of a solution of 1-bromo-1-propene (7.25 g, 0.06 mole) in dry THF (50 ml). After warming to initiate the reaction, the remaining bromopropene solution was added dropwise at a rate to maintain reflux. After addition, the reaction was heated at reflux for a further hour, cooled and added rapidly to a stirred solution of 2-bromonitrobenzene (4.04 g, 0.02 mole) in dry THF (70 ml) at -40° C. under nitrogen. The reaction mixture was stirred for a further 30 minutes at -40° C., then was quenched with saturated aqueous ammonium chloride and extracted into diethyl ether. The combined organic extracts were washed with water, dried, filtered and evaporated in vacuo. The crude product was purified by flash chromatography on silica, eluting with 25% diethyl ether in hexane, to yield a yellow-orange oil.

Provenance & Evidence