methyl 4-bromo-2,3,5,6-tetrafluorobenzoate

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

Procedure: A toluene/Water (175 mL+25 mL) mixture was degassed with nitrogen for 30 minutes. Cesium carbonate (14.9 g, 43.55 mmol) was added followed by 4-bromo-2,3,5,6-tetrafluoro-benzoic acid methyl ester (5.0 g, 17.42 mmol), 4-formyl boronic acid (3.4 g, 22.64 mmol) and dichlorobis(triphenylphosphine)-palladium(II) catalyst (0.611 g, 0.87 mmol). The reaction mixture was refluxed for 15 h. TLC shows completion of the reaction. The reaction mixture was cooled to room temperature and was extracted with ethyl acetate. The combined organic layers were dried over sodium sulphate and concentrated. The obtained residue was purified by column chromatography using 5% ethyl acetate in hexane to get colorless solid (3.0 g, 55.24%). A toluene/Water (175 mL+25 mL) mixture was degassed with nitrogen for 30 minutes The reaction mixture was refluxed for 15 h completion of the reaction was extracted with ethyl acetate The combined organic layers were dried over sodium sulphate concentrated The obtained residue was purified by column chromatography

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

Procedure: A mixture of toluene (370 mL) and water (70 mL) was degassed with nitrogen for 30 minutes. A mixture of cesium carbonate (102.6 g, 315 mmol), 4-bromo-2,3,5,6-tetrafluoro-benzoic acid methyl ester (30.0 g, 105 mmol), phenyl boronic acid (19.26 g, 157 mmol) and tetrakis triphenyl phosphene palladium(0) (11.5 g, 9.9 mmol) were added to the above degassed water/toluene mixture. The reaction mixture was refluxed overnight. After the reaction is completed, it was cooled to room temperature and extracted with ethyl acetate. The combined organic layers were dried over sodium sulphate and concentrated. The resulting residue was purified by column chromatography using 5% ethyl acetate in hexane to obtain the title compound (26.5 g, 88.6%). was degassed with nitrogen for 30 minutes were added to the above degassed water/toluene mixture The reaction mixture was refluxed overnight extracted with ethyl acetate The combined organic layers were dried over sodium sulphate concentrated The resulting residue was purified by column chromatography

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

Procedure: To a solution of 4-bromo-2,3,5,6-tetrafluoro-benzoic acid (20 g, 73.49 mmol) in methanol (20 mL) was added an ethereal solution of diazomethane gas until the starting material is completely consumed. Reaction mixture was then evaporated under reduced pressure. The crude solid obtained was purified by flash column chromatography using 5% ethyl acetate in hexane, to obtain title compound as colorless crystalline solid (18 g, 85%). is completely consumed Reaction mixture was then evaporated under reduced pressure The crude solid obtained was purified by flash column chromatography