反应详情

温度

-78 °C

1,5-Bis(3,4-dimethoxyphenyl)-1,4-pentadien-3-one (20i, 0.56 g, 1.6 mmol) was dissolved in dichloromethane (10 ml) and stirred under a nitrogen atmosphere at −78° C. for 5 min. Boron tribromide (0.90 ml, 9.5 mmol) was added and stirring continued for 60 min at −78° C., 60 min at 0° C. and 60 min at room temperature. The mixture was poured into hydrochloric acid (30 ml, 1 N) and stirring was continued for 18 hr at room temperature. The resulting mixture was extracted into ethyl acetate, washed with water and saturated sodium chloride, dried over magnesium sulfate, filtered and evaporated to afford a solid. The crude solid was chromatographed on silica gel with ethyl acetate/hexane to give 0.36 g (76%) of an orange solid: mp>250° C. [expected mp 221-223° C.]; 1H NMR: (DMSO) δ 6.78 (d, 2H, J=8.1 Hz), 6.99 (d, 2H, J=15.9 Hz), 7.06 (d, 2H, J=7.9 Hz), 7.14 (s, 2H), 7.55 (d, 2H, J=15.7 Hz), 9.15 (s, 2H), 9.63 (s, 2H); 13C NMR: (DMSO) δ 114.9, 115.6, 121.5, 122.5, 126.2, 142.5, 145.4, 148.2, 187.6.

1. stirringstirring
2. waitcontinued for 60 min at −78° C., 60 min at 0° C. and 60 min at room temperature
3. stirringstirring
4. waitwas continued for 18 hr at room temperature
5. extractionThe resulting mixture was extracted into ethyl acetate
6. washwashed with water and saturated sodium chloride
7. dry with materialdried over magnesium sulfate
8. filtrationfiltered
9. customevaporated
10. customto afford a solid
11. customThe crude solid was chromatographed on silica gel with ethyl acetate/hexane