Hydroxyphenylacetic acid → Benzeneacetic acid, 4-(2-bromoethoxy)-, methyl ester

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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 1by 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, 2), 2.61 (m, 1H); ES-MS (m/z) 458 [M+H]+.

Provenance & Evidence