反应详情

温度

8.5 °C

A freshly prepared solution of bromine (258.9 g) in methanol (600 mL) was added dropwise during 1 h 20 min to a stirred solution of benzylacetone (222.3 g) in methanol (600 mL) at 7-10° C. An exothermic reaction took place, and to maintain the necessary temperature (7-10° C.), the flask should be immersed in a ice-water bath. When orange-red color of bromine disappeared, water (1500 mL) was added to the mixture and the obtained mixture was stirred overnight. The organic layer (on the bottom) was separated, water phase was extracted with dichloromethane (2×600 mL). The combined organic layers were dried over sodium sulfate, filtered and evaporated under reduced pressure. The oily residue was dissolved in hexane (2500 mL) and the obtained solution was kept overnight at −10° C. Precipitated fine crystals (needles) were filtered off, washed on filter with cold hexane, dried under reduced pressure at room temperature to give 1-bromo-4-phenyl-2-butanone (213.0 g, 63% yield), mp 39-40° C. 1H NMR (CDCl3) δ 2.95-3.00 (m, 4H); 3.83 (s, 2H); 7.16-7.30 (m, 5H).

1. customAn exothermic reaction
2. customthe flask should be immersed in a ice-water bath
3. customThe organic layer (on the bottom) was separated
4. extractionwater phase was extracted with dichloromethane (2×600 mL)
5. dry with materialThe combined organic layers were dried over sodium sulfate
6. filtrationfiltered
7. customevaporated under reduced pressure
8. dissolutionThe oily residue was dissolved in hexane (2500 mL)
9. waitthe obtained solution was kept overnight at −10° C
10. customPrecipitated fine crystals (needles)
11. filtrationwere filtered off
12. washwashed
13. filtrationon filter with cold hexane
14. customdried under reduced pressure at room temperature