1,2-Dibromoethane → 6-(2-Bromoethoxy)-7-propyl-3-(trifluoromethyl)1,2-benzisoxazole

Beteiligte Stoffe

Reaktionsschritte

3-Trifluoromethyl-7-propyl-6-hydroxy-benzisoxazole (1 g, 4.1 mmol) prepared in Example 24, 1,2-dibromoethane (3.7 g, 18.3 mmol) and NaOH (6 M aqueous solution, 1 mL, 6.0 mmol) were combined and stirred under reflux for 4.5 h. A second portion of NaOH (6 M aqueous solution, 0.43 mL, 2.6 mmol) was added, and stirring under reflux was continued for 4 h. Upon cooling to rt, water (10 mL) was added and the mixture was extracted with CH2Cl2 (3×). The combined organic phases were washed with NaOH (5 M aqueous solution, 2×) and water (3×). The organic phase was dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel flash chromatography (EtOAc/hexanes (v/v) 1:9) to obtain 550 mg (38%) of the title compound as colorless crystals. 1H NMR (300 MHz, CDCl3): δ 0.99 (t, 3H), 1.72 (dt, 2H), 2.94 (t, 2H), 3.70 (t, 2H), 4.42 (t, 2H), 7.03 (d, 1H), 7.58 (d, 1H).

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