4-bromo-2,5-dimethylphenol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred suspension of 2,5-dimethyl phenol (5.0 g, 40.9 mmol) in H2O (150 mL), at room temperature was added tetrabutylammonium tribromide (19.9 g, 41.39 mmol) in CHCl3 (150 mL). The reaction mixture was stirred for 2 h at rt, the organic layer was separated and dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography on silica gel eluting with hexane-ethyl acetate (1:5) to afford 2,5-dimethyl-4-bromophenol as a brown solid (6.2 g, 76%); 1H NMR (300 MHz, DMSO-d6): δ 9.47 (s, 1H), 7.24 (s, 1H), 6.74 (s, 1H), 2.21 (s, 3H), 2.07 (s, 3H); TLC conditions: Uniplate silica gel, 250 microns; Mobile phase=hexanes-ethyl acetate (9:1); Rf=0.52. the organic layer was separated dried over Na2SO4 filtered concentrated The residue was purified by column chromatography on silica gel eluting with hexane-ethyl acetate (1:5)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred suspension of 2,5-dimethyl phenol (5.0 g, 40.9 mmol) in H2O (150 mL), at room temperature was added tetrabutylammonium tribromide (19.9 g, 41.39 mmol) in CHCl3 (150 mL). The reaction mixture was stirred for 2 h at rt, the organic layer was separated and dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography on silica gel eluting with hexane-ethyl acetate (1:5) to afford 2,5-dimethyl-4-bromophenol as a brown solid (6.2 g, 76%); 1H NMR (300 MHz, DMSO-d6): δ 9.47 (s, 1 H), 7.24 (s, 1 H), 6.74 (s, 1 H), 2.21 (s, 3 H), 2.07 (s, 3 H); TLC conditions: Uniplate silica gel, 250 microns; Mobile phase=hexanes-ethyl acetate (9:1); Rf=0.52. the organic layer was separated dried over Na2SO4 filtered concentrated The residue was purified by column chromatography on silica gel eluting with hexane-ethyl acetate (1:5)