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Sodium ethanolate solution was prepared by dissolving sodium metal (33.5 g, 1.46 mol) in ethanol (1.0 L) under nitrogen protection. Ethyl 4-bromo-2-nitrophenylacetate (420 g, 1.46 mol) was dissolved in ethanol (3 L) in a 10 L three-necked round-bottomed flask, isoamyl nitrite (225 mL) was added, and the mixture was subsequently heated to 60 °C. A pre-prepared sodium ethanolate solution (prepared from sodium metal 33.5 g, 1.46 mmol dissolved in ethanol 1 L) was added slowly dropwise and after completion of the dropwise addition, the reaction mixture was maintained to continue the reaction at this temperature for 2 hours. After completion of the reaction, the mixture was cooled to room temperature and neutralized with 2N hydrochloric acid. The reaction mixture was extracted with ethyl acetate (4 × 2 L), the organic phases were combined, washed sequentially with water (2 × 1 L) and saturated brine (2 × 1 L) and dried over anhydrous sodium sulfate. Finally, the residue was purified by column chromatography (eluent ratio from 1/1 to 0/1 hexane/ethyl acetate) to afford 110 g of ethyl 6-bromobenzisoxazole-3-carboxylate in 28% yield.

[1] Patent: WO2005/63767, 2005, A2. Location in patent: Page/Page column 44
[2] Patent: US2005/250808, 2005, A1. Location in patent: Page/Page column 40
[3] Patent: US2007/78147, 2007, A1. Location in patent: Page/Page column 72