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

Temperature

120 °C

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).

1. temperatureto cool to ambient temperature
2. concentrationconcentrated in vacuo
3. dissolutionThe residue was dissolved in ethyl acetate
4. washwashed with 1N hydrochloric acid (3 20 mL), water (20 mL) and brine (20 mL)
5. dry with materialThe organic phase was dried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe residue was triturated in hexanes/diethyl ether (1:1 v/v, 50 mL)
9. washwashed with hexanes (20 mL)

ORD record

ord-f17f3969b37641ba80d245cbcd950890

Source dataset

uspto-grants-2016_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09365578B2