103068-40-2

General procedure for the demethylation of BBr3: 2-fluoro-3-methoxyphenol (8.7 mmol) was dissolved in dry dichloromethane (40 mL) under nitrogen protection and cooled to -78°C. BBr3 (1 M solution in dichloromethane, 4 equivalents per methoxide) was added slowly and dropwise. The reaction mixture was stirred at -78 °C overnight, during which time the cooling bath was allowed to warm naturally to room temperature. Upon completion of the reaction, the mixture was cooled again to -78 °C and the reaction was quenched by careful dropwise addition of water. The aqueous layer was extracted with EtOAc, the organic layers were combined and dried over anhydrous Na2SO4. The solvent was evaporated under reduced pressure to give the crude product. The crude product was ground with EtOAc to give 2-fluoro-1,3-benzenediol, which could be used in subsequent reactions without further purification. The yield of the method was 93%. Mass spectrometry (MS) data: m/z 129.1 (MH+).

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