Sodium Carbonate → 4-(7-Bromo-1,3-benzodioxol-4-yl)-4-methyl-2-oxo-valeric acid-ethyl ester

Participants

Reaction Conditions

Reaction Steps

1.77 g of 2-(7-bromobenzo[1,3]dioxol-4-yl)-propan-2-ol and 2.82 g of 2-trimethylsilyloxy-acrylic acid-ethyl ester (WO 00/32584) in 36 ml of dichloromethane are mixed at −70° C. with 1.10 ml of tin(VI)chloride. It is stirred for 20 minutes at −70° C. and then added to saturated sodium carbonate solution. It is extracted with dichloromethane, washed with water, dried and concentrated by evaporation in a vacuum. 3.15 g of 4-(7-bromo-1,3-benzodioxol-4-yl)-4-methyl-2-oxo-valeric acid-ethyl ester is obtained as a crude product. The latter is reacted for 4 hours at room temperature in 57 ml of a mixture that consists of 1N sodium hydroxide solution in ethanol/water. The batch is added to water, extracted with ether and then the aqueous phase is acidified with hydrochloric acid. It is extracted with ethyl acetate, washed with water, dried with sodium sulfate and concentrated by evaporation in a vacuum. 2.1 g of 4-(7-bromo-1,3-benzodioxol-4-yl)-4-methyl-2-oxo-valeric acid is obtained as a yellow oil.

Provenance & Evidence