Methanol → 4-(2-bromoethoxy)-phenylacetic acid

Participants

Reaction Conditions

Reaction Steps

4-Hydroxyphenylacetic acid (100 g, 0.6 mol) and cesium carbonate (250 g) were suspended in 300 mL of anhydrous acetonitrile followed by addition of 1,2-dibromoethane (300 mL). The suspension was brought to reflux for 24 hours in a 2 L 3 neck round bottom flask fitted with a mechanical stirrer and reflux condenser then cooled to room temperature. The mixture was diluted to a volume of 2 L by addition of ethyl ether and the suspension was filtered. Concentration of the filtrate in vacuo afforded a colorless oil which was purified by vacuum distillation (0.2 mm Hg, 140-145° C.) to give methyl 4-(2-bromoethoxy)-phenylacetate (93.14 g, 60% yield) as a colorless oil. The methyl 4-(2-bromoethoxy)-phenylacetate was taken into methanol (250 mL) and the resulting solution was cooled to 0° C. Sodium hydroxide (29 g) in a minimum of water was added to the methanol solution in portions and the mixture was stirred at 0° C. for an additional 30 minutes. The solution was warmed to room temperature then concentrated to a white solid. The residue was taken into water and the solution washed once with ethyl ether. The aqueous solution was then acidified to pH 1 by addition of concentrated aqueous hydrochloric acid to give a thick suspension. Filtration and drying afforded 4-(2-bromoethoxy)-phenylacetic acid (86 g, 97% yield) as a colorless solid. The 4-(2-bromoethoxy)-phenylacetic acid (50 g) was taken into thionyl chloride (70 mL) and brought to reflux under an atmosphere of nitrogen for 2 hours. Fractional vacuum distillation (0.2 mm Hg, 139-140° C.) afforded 4-(2-bromoethoxy)phenylacetyl chloride (46.0 g, 86% yield) as a colorless oil that quickly crystallized on cooling. 1H NMR (CDCl3) 6.95, 6.76, 6.60 (m, 11H, Ar—H), 4.68 (m, 1H), 4.24 (m, 2H), 3.80 (m, 1H), 3.41-3.63 (m, 3H), 3.07 (m, 1H), 2.87 (m, 2H), 2.61 (m, 1H); ES-MS (m/z) 458 [M+H]+.

Provenance & Evidence