反应详情

A solution of Example 385A (10.5 g, 54.4 mmol) in DMF (100 mL) and dichloromethane (200 mL) was cooled to 0° C., treated portionwise with NBS (14.4 g, 80.9 mmol) over 40 minutes, stirred overnight at room temperature and filtered. The filtrate was concentrated to provide the desired product (˜20 g) which was used directly in the next step.

1. filtrationfiltered
2. concentrationThe filtrate was concentrated