反应详情

To a chilled solution of the product of Step F (343.60 g) in EtOAc (4 L) was added N-bromosuccinimide (237.60 g) followed by stirring at rt for 18 h. To the mixture was added water (5 mL) and the reaction heated to 60° C. for 30 min. The reaction was filtered, the filtrate was washed with aqueous sodium thiosulfate until the organic layer was negative for peroxides. The organic layer was washed with aqueous Na2CO3 (10%), dried (Na2SO4) and the reaction was concentrated under reduced pressure. Near the end of the concentration, heptane (1.2 L) was added, and the product was collected by filtration to provide the product of Step G. 1H NMR (400 MHz, CHLOROFORM-d) δ=4.78-4.91 (m, 1H), 4.41 (br. s., 1H), 4.31 (s, 2H), 3.88-3.98 (m, 1H), 3.61-3.77 (m, 3H), 2.08-2.24 (m, 1H), 1.82 (m, 2H), 1.60-1.70 (t, 1H), 1.45 (s, 9H)

1. temperaturethe reaction heated to 60° C. for 30 min
2. filtrationThe reaction was filtered
3. washthe filtrate was washed with aqueous sodium thiosulfate until the organic layer
4. washThe organic layer was washed with aqueous Na2CO3 (10%)
5. dry with materialdried (Na2SO4)
6. concentrationthe reaction was concentrated under reduced pressure
7. concentrationNear the end of the concentration, heptane (1.2 L)
8. additionwas added
9. filtrationthe product was collected by filtration