Optimization of the bromination reaction and conditions.

Entry	Condition	Time (min)	Yielda (%)
1b	Br2 (1 eq.), AcOH (1.2 eq.), ACN, rt	60	36
2	Br2 (3 eq.), ACH, 30 °C	2	48
3	Br2 (4.5 eq.), ACN, 30 °C	2	22
4	Br2 (3 eq.), ACN, 60 °C	2	32
5	Br2 (3 eq.), ACN, 30 °C	4	28
6	Br2 (3 eq.), MeOH, 30 °C	2	44
7	Br2 (3 eq.), ACN, 30 °C	0.55	64

^aIsolated yield.

^bIn a batch process.