反应详情

At 0° C. to a solution of 2-{benzenesulfonyl-[2-(3-bromo-phenyl)-2-hydroxy-ethyl]-amino}-N-phenyl-acetamide (1.15 g) and triphenylphosphine (678 mg) in ethylacetate (10 mL) was added a solution of diethylazodicarboxylate (0.4 mL) in ethylacetate (5 mL) dropwise. After 15 min. the cooling bath was removed and the mixture was stirred at RT for 3 h. Additional amounts of triphenylphosphine (31 mg) and diethylazodicarboxylate (0.18 mL) were added, and stirring was continued for 1 h. The mixture was diluted with water and ethyl acetate, the phases were separated, and the inorganic one was extracted with ethyl acetate (×2). The organic layers were combined, washed with brine, dried (Na2SO4) and concentrated in vacuo. The crude product was purified by flash chromatography (SiO2, n-heptane/ethyl acetate 7:3) to give 4-benzenesulfonyl-6-(3-bromo-phenyl)-1-phenyl-piperazin-2-one (0.99 g, 89%) as a white foam, MS: 471.4 (M+H, 1Br)+.

1. customAfter 15 min. the cooling bath was removed
2. additionAdditional amounts of triphenylphosphine (31 mg) and diethylazodicarboxylate (0.18 mL) were added
3. stirringstirring
4. waitwas continued for 1 h
5. additionThe mixture was diluted with water and ethyl acetate
6. customthe phases were separated
7. extractionthe inorganic one was extracted with ethyl acetate (×2)
8. washwashed with brine
9. dry with materialdried (Na2SO4)
10. concentrationconcentrated in vacuo
11. customThe crude product was purified by flash chromatography (SiO2, n-heptane/ethyl acetate 7:3)