Potassium Carbonate → 2-Bromo-1-cyclopentylethanone

Participants

Reaction Steps

To a solution of 16.1 g (0.143 mol) of acetylcyclopentane in 175 ml of methanol cooled in an ice bath was added 7.7 ml (0.15 mol) of bromine during 5 min. The reaction mixture was then allowed to warm to 10°-15° and held there by occasional application of the ice bath for 45 min until the reaction mixture became colorless. Then 100 ml of water was added and it was allowed to stir at room temperature for 0.5 hr. It was partially neutralized by the cautious addition of 10 g (72 mmol) of solid potassium carbonate, diluted with 200 ml of water and extracted with 4×150 ml of ether. The combined organic extracts were washed with 2×100 ml of saturated sodium bicarbonate solution and with 3×100 ml of water, dried over magnesium sulfate and concentrated in vacuo at room temperature to leave 30 g (110%) of bromoacetylcyclopentane as an oil whose nmr spectrum indicated that it was mainly the desired product.

Provenance & Evidence