1-(benzo[d][1,3]dioxol-5-yl)-2-bromobutan-1-one synthesis

Yield:1266804-81-2 84%

Reaction Conditions:

with bromine;acetic acid at 20; for 2 h;

Steps:

1 Example 1: Synthesis of (RS)-1-(benzo[d][1,3]dioxol-5-yl)-2-bromobutanone

To a solution of 1-(benzo[d][1,3]dioxol-5-yl)butanone (25g, 0.13 mole) in acetic acid (100ml) was added dropwise a solution of bromine (21.8g, 0.137 mole) in acetic acid (100ml). The reaction mixture was then stirred at room temperature for two hours. Acetic acid was removed under high vacuum. Water (200ml) was added to the mixture and the solution was extracted with dichloromethane (2x200m1). The combined organic layers were washed with saturated NaHCO₃ solution (100ml), water (100ml) and brine (100ml). The dichloromethane solution was dried over Na₂SO₄, filtered and concentrated to dryness under vacuum. The crude product obtained was purified by chromatography on silica gel using 5% ethyl acetate in hexane to give the title compound (29.6g, 84%).

References:

EP2626358,2013,A1 Location in patent:Paragraph 0016