反应详情

温度

18 °C

A stirred mixture of 5-(2-hydroxyphenyl)benzofurazan (11.2 g, 52.8 mmol), and tetrabutylammonium tribromide (25.5 g, 52.8 mmol) in dichoromethane (530 mL) is stirred at 18° C. for 18 h. The solvent is evaporated off under reduced pressure to yield a residue which is treated with water (300 mL) and extracted with ethyl acetate (3×100 mL). The combined extracts are washed (saturated NaCl), dried (Na2SO4), filtered and the solvent is evaporated off under reduced pressure to yield the crude product which is purified by recrystallisation from ethyl acetate-hexane to give 5-(3-bromo-6-hydroxyphenyl)benzofurazan as a pale-yellow crystalline solid, m.p. 179-181° C.

1. customThe solvent is evaporated off under reduced pressure
2. customto yield a residue which
3. extractionextracted with ethyl acetate (3×100 mL)
4. washThe combined extracts are washed (saturated NaCl)
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. customthe solvent is evaporated off under reduced pressure
8. customto yield the crude product which
9. customis purified by recrystallisation from ethyl acetate-hexane