Azobisisobutyronitrile → 4-(Bromomethyl)-2-(trifluoromethyl)benzoic acid

Participants

Reaction Conditions

Reaction Steps

A suspension of 4-methyl-2-trifluoromethyl-benzoic acid (commercially available) (20.242 g), N-bromosuccinimide (“NBS”) (19.52 g) and 2,2′-azobis-(2-methylpropanenitrile) (“AIBN”) (0.859 g) in α,α,α-trifluorotoluene (160 ml) was heated to 90° C. for 1.5 hours. The reaction mixture was allowed to cool to ambient temperature and then diluted with ethyl acetate (200 ml) and aqueous hydrochloric acid (1M) (100 ml). The phases were separated and the organic phase was washed with aqueous hydrochloric acid (1M) (100 ml) and brine (150 ml), dried over sodium sulfate and concentrated. The residue was triturated with dichloromethane (40 ml). The solids were isolated by filtration and dried to give 4-bromomethyl-2-trifluoromethyl-benzoic acid (5.01 g) as a white powder. The filtrate was concentrated, re-dissolved in heptane/dichloromethane (1:1) (40 ml) and the dichloromethane slowly evaporated to initiate crystallization. The solids were isolated by filtration, rinsed with pentane and dried to give a second fraction of 4-bromomethyl-2-trifluoromethyl-benzoic acid (7.00 g) as a white powder. 1H-NMR (CDCl3, 400 MHz): 11.5 (br s, 1H), 8.03-7.20 (m, 3H), 4.52 (s, 2H).

Provenance & Evidence