1,1'-Carbonyldiimidazole → 2-Benzoxazolinone, 5-bromo-

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Reaction Conditions

Reaction Steps

A mixture of 2-amino-4-bromophenol (6.0 g, 31.9 mmol) and 1,1′-carbonyldiimidazole (6.2 g, 38.3 mmol) in p-dioxane (30 mL) was heated at 120° C. for 3 h, allowed to cool to ambient temperature and concentrated in vacuo. The residue was dissolved in ethyl acetate and washed with 1N hydrochloric acid (3 20 mL), water (20 mL) and brine (20 mL). The organic phase was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was triturated in hexanes/diethyl ether (1:1 v/v, 50 mL) and washed with hexanes (20 mL) to afford 5-bromobenzo[d]oxazol-2(3H)-one in 91% yield (6.2 g) as a beige solid: 1H NMR (300 MHz, DMSO-d6) δ11.85 (br s, 1H), 7.28-7.25 (m, 3H); MS (ES+) m/z 212.0 (M+1), 214.0 (M+1).

Provenance & Evidence