Substrate Directed Regioselective Monobromination of Aralkyl Ketones Using N-Bromosuccinimide Catalysed by Active Aluminium Oxide: α-Bromination versus Ring Bromination

Table 6

Effect of solvent on nuclear bromination of 4′-Hydroxy acetophenone (1p)^a.

Entry	Solvent	Time/min	Product	Yield^b/%
1	MeOH	12	4a	86
2	EtOH	60	4a	61
3	H2O	24 hrs	4a	22
4	CH3CN	14	4a	94
^c5	^dEther	45	4a	48
6	^dTHF	75	4a	40
7	CH2Cl2	150	4a	30
8	CHCl3	90	4a	34

aReaction conditions: 4′-hydroxy acetophenone 1p (10 mmol), N-bromosuccinimide (12 mmol), 10% (w/w) neutral Al₂O₃, and solvent (20 vol) at reflux temperature.
bIsolated yield.
cReaction was conducted at 32°C.
dFreshly distilled ether and THF were used (peroxide free).