反应详情

To 33% HBr in acetic acid (1.33 L) was added the title compound of Example 5 (403.4 g, 766 mmol) and the stirred vigorously for 1 hour and 20 min. The mixture was slowly and carefully added to MTBE (12 L) with external cooling and strong agitation. The mixture was stirred for 1 hour at 0° C. and filtered under N2. The hygroscopic solids were washed with MTBE (1 L) and dried to constant mass in a vacuum oven to yield the title compound (277.5 g, 76.5%) as a fine brown solid. 1H NMR (CDCl3): consistent with proposed structure.

1. temperaturewith external cooling
2. stirringThe mixture was stirred for 1 hour at 0° C.
3. filtrationfiltered under N2
4. washThe hygroscopic solids were washed with MTBE (1 L)
5. customdried to constant mass in a vacuum oven