N-bromobutanimide → HCID 22227144, compound

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Reaction Steps

Using a 200 ml Erlenmeyer flask, 7.00 g (35.89 millimoles) of 7-bromoindene produced by the method described in J. Org. Chem. 49, 4226–4237(1984) was dissolved in a mixed solvent of 1.42 g (79.00 millimoles) of distilled water and 70 ml of dimethyl sulfoxide. To this reaction solution there was added 7.67 g (43.07 millimoles) of N-bromosuccinimide while cooling on ice, and the mixture was then stirred for one hour at room temperature. After hydrolysis with distilled water while cooling on ice, extraction was performed several times with diethyl ether, and the extract was washed with saturated saline and then dried over anhydrous magnesium sulfate. After filtration of the magnesium sulfate, the solvent was distilled off under reduced pressure. The obtained product was transferred to a 200 ml Erlenmeyer flask and dissolved in 100 ml of toluene. To this solution there was added 0.68 g (3.59 millimoles) of p-toluenesulfonic acid hydrate, and the mixture was heated to reflux for 4 hours. After reflux, hydrolysis was performed with distilled water while cooling on ice, and extraction was performed several times with diethyl ether. The extract was washed once with a saturated sodium bicarbonate aqueous solution, washed once with saturated saline, and then dried over anhydrous magnesium sulfate. After drying, the magnesium sulfate was filtered off, the solvent was distilled off under reduced pressure, and purification was performed with a silica gel column to obtain 6.6 g of 2,7-dibromoindene as white crystals (67% yield).

Provenance & Evidence