反应详情

To a stirred solution of the product from Step B, (2.05 g, 6.08 mmol) in acetic acid (50 mL) was added N-bromosuccinimide (1.14 g, 6.38 mmol) in one portion. The reaction mixture was stirred at ambient temperature for 2 hrs, then H2O (100 mL) and CH2Cl2 (100 mL) were added and the resulting mixture was cooled to 0° C. The aqueous layer was adjusted to pH of about 7 by addition of 10 N aqueous NaOH and the organic layer was extracted. The aqueous phase was extracted with a further portion of CH2Cl2 (100 mL), and the combined organic extracts were dried over Na2SO4, filtered, and concentrated in vacuo. The residue was triturated with 1:1 hexane-EtOAc to provide the titled product as a grey solid.

1. temperaturethe resulting mixture was cooled to 0° C
2. extractionthe organic layer was extracted
3. extractionThe aqueous phase was extracted with a further portion of CH2Cl2 (100 mL)
4. dry with materialthe combined organic extracts were dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customThe residue was triturated with 1:1 hexane-EtOAc