2-amino-5-bromo-3-fluorophenol

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-3-fluorophenol (1 equiv), ytterbium(iii) trifluoromethanesulfonate (0.01 equiv), and trimethyl orthoacetate (1.2 equiv) in EtOH (1.3 M) was heated to 90° C. for 2 h. The reaction mixture was filtered through celite and washed with EtOH. The residual filtrate was concentrated in vacuo, then saturated aqueous sodium bicarbonate added and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified using silica gel chromatography (0 to 60% ethyl acetate in hexane) to afford the title compound (73% yield). MS (ESI) m/z 232.2 [M+H]+. The reaction mixture was filtered through celite washed with EtOH The residual filtrate was concentrated in vacuo saturated aqueous sodium bicarbonate added extracted with ethyl acetate The combined organic layers were dried over sodium sulfate filtered concentrated in vacuo The residue was purified

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

Procedure: To a suspension of 4-bromo-2-fluoro-6-methoxyaniline hydrobromide (1 equiv) in DCM (0.3 M) was added boron tribromide (2 equiv) in DCM at 0° C. The reaction mixture was stirred at room temperature for 2 h. After quenching, the reaction mixture was diluted with DCM then purified by silica gel chromatography (0 to 100% ethyl acetate in hexane) to give the title compound (92% yield). MS (ESI) m/z 205.9 [M+H]+. After quenching the reaction mixture was diluted with DCM then purified by silica gel chromatography (0 to 100% ethyl acetate in hexane)