反应详情

温度

-70 °C

To a solution of 1-(4-methoxy-3-nitro-phenyl)-cyclopropane-carboxylic acid methyl ester (10.0 g, 39.8 mmol) in CH2Cl2 (100 mL) was added BBr3 (12.0 g, 47.8 mmol) at −70° C. The mixture was stirred at −70° C. for 1 hour, then allowed to warm to −30° C. and stirred at this temperature for 3 hours. Water (50 mL) was added dropwise at −20° C., and the resulting mixture was allowed to warm room temperature before it was extracted with EtOAc (200 mL×3). The combined organic layers were dried over anhydrous Na2SO4 and evaporated under vacuum to give the crude product, which was purified by column chromatography on silica gel (petroleum ether/EtOAc 15:1) to afford 1-(4-hydroxy-3-nitro-phenyl)-cyclopropanecarboxylic acid methyl ester (8.3 g, 78%). 1H NMR (CDCl3, 400 MHz) δ 10.5 (s, 1H), 8.05 (d, J=2.4 Hz, 1H), 7.59 (dd, J=2.0, 8.8 Hz, 1H), 7.11 (d, J=8.4 Hz, 1H), 3.64 (s, 3H), 1.68-1.64 (m, 2H), 1.20-1.15 (m, 2H).

1. temperatureto warm to −30° C.
2. stirringstirred at this temperature for 3 hours
3. temperatureto warm room temperature before it
4. extractionwas extracted with EtOAc (200 mL×3)
5. dry with materialThe combined organic layers were dried over anhydrous Na2SO4
6. customevaporated under vacuum
7. customto give the crude product, which
8. customwas purified by column chromatography on silica gel (petroleum ether/EtOAc 15:1)