3,5-Difluoroanisole

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3,5-difluoroanisole (30 g, 208 mmol) in 260 mL dichloromethane was added HNO3 (>90% fuming, 60 mL) dropwise at 0° C. The resulting solution was stirred at 0° C. for 3 hours, then washed water. The aqueous phase was extracted with dichloromethane. The organic phase was washed with brine, dried over magnesium sulfate and condensed on a rotavap. The residue was recrystallized in hexane and ethyl acetate to provide 28.5 g (72% yield) of 1,5-difluoro-3-methoxy-2-nitrobenzene as an off-white powder. 1H NMR (400 MHz, DMSO) δ ppm 7.20 (m, 2H), 3.91 (s, 3H). The aqueous phase was extracted with dichloromethane The organic phase was washed with brine dried over magnesium sulfate and condensed on a rotavap The residue was recrystallized in hexane

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3,5-difluoroanisole (30 g, 208 mmol) in 260 mL dichloromethane was added HNO3 (>90% fuming, 60 mL) dropwise at 0° C. The resulting solution was stirred at 0° C. for 3 hours, then washed water. The aqueous phase was extracted with dichloromethane. The organic phase was washed with brine, dried over magnesium sulfate and condensed on a rotavap. The residue was recrystallized in hexane and ethyl acetate to provide 28.5 g (72% yield) of 1,5-difluoro-3-methoxy-2-nitrobenzene as an off-white powder. 1H NMR (400 MHz, DMSO) δ ppm 7.20 (m, 2H), 3.91 (s, 3H). The aqueous phase was extracted with dichloromethane The organic phase was washed with brine dried over magnesium sulfate and condensed on a rotavap The residue was recrystallized in hexane

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a THF (100 ml) solution of 1,3-difluoro-5-methoxybenzene (7 g, 48.6 mmol) was added dropwise 1.6 M hexane solution of n-butyllithium (30 ml, 48.6 mmol) at −78° C. over 30 minutes and the mixture was stirred for 2 hours at −78° C. Then 1,1,1-Trifluoroacetone (6.5 g, 58.3 mmol) was added at −78° C. and the mixture was stirred for 2 hours at −78° C. After stirring at room temperature for an additional 1 hour, the reaction was quenched with water. The whole was extracted with EtOAc and the organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo. Purification by silica gel column chromatography eluting with hexane/EtOAc (10:1) gave the title compound (9.7 g, 78% yield) as a colorless oil. the mixture was stirred for 2 hours at −78° C After stirring at room temperature for an additional 1 hour the reaction was quenched with water The whole was extracted with EtOAc the organic layer was dried over sodium sulfate filtered concentrated in vacuo Purification by silica gel column chromatography eluting with hexane/EtOAc (10:1)

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

Procedure: (Intermediates 26A and 26B were prepared in a similar manner to the preparation described in WO 2004046133). To a stirred solution of 3,5-difluoroanisole (1.0 g, 7.0 mmol) in dichloromethane (6 mL) at 0° C. was added dropwise titanium tetrachloride (1.23 mL, 11.2 mmol) and dichloromethyl methyl ether (0.63 mL, 7.0 mmol). Upon completion of addition, the reaction mixture was stirred for 1 h and then poured into ice-water (50 mL). The resulting mixture was extracted with dichloromethane (3×50 mL). The combined organics were washed with H2O (50 mL), brine (50 mL), dried over Na2SO4 and filtered. The volatiles were removed under reduced pressure to provide a residue. The residue was subjected to chromatography on silica gel eluting with 0 to 20% EtOAc/hexanes to give 2,6-difluoro-4-methoxybenzaldehyde, Intermediate 26A [less polar material, 230 mg, 19%, 1H NMR (400 MHz, CDCl3) δ ppm 3.85 (s, 3 H), 6.47 (d, J=10.55 Hz, 2 H), 10.17 (s, 1 H)] and 2,4-difluoro-6-methoxybenzaldehyde, Intermediate 26B [more polar material, 740 mg, 62%, 1H NMR (400 MHz, CDCl3) δ ppm 3.91 (s, 3 H) 6.43-6.51 (m, 2 H) 10.30 (s, 1 H)], both as white solids. (Intermediates 26A and 26B were prepared in a similar manner to the preparation Upon completion of addition The resulting mixture was extracted with dichloromethane (3×50 mL) The combined organics were washed with H2O (50 mL), brine (50 mL) dried over Na2SO4 filtered The volatiles were removed under reduced pressure to provide a residue

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

Procedure: A solution of n-butyllithium (10.0M in hexane; 25.0 ml, 0.25 mol) was added dropwise to a stirred, cooled (-78° C.) solution of 3,5-difluoroanisole (35.9 g, 0.25 mol) in dry THF (200 ml) under dry nitrogen. The stirred mixture was maintained under these conditions for 2.5 h and then poured into a slurry of solid carbon dioxide and dry ether. The product was extracted into 10% sodium hydroxide (twice), the combined basic extracts were acidified with 36% hydrochloric acid, and the product was extracted into ether (twice), the combined ethereal extracts were washed with water and dried (MgSO4). The solvent was removed in vacuo to give a colourless solid. The stirred mixture was maintained under these conditions for 2.5 h The product was extracted into 10% sodium hydroxide (twice), the combined basic extracts the product was extracted into ether (twice), the combined ethereal extracts were washed with water dried (MgSO4) The solvent was removed in vacuo to give a colourless solid

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3,5-difluoroanisole (30 g, 208 mmol) in 260 mL dichloromethane was added HNO3 (>90% fuming, 60 mL) dropwise at 0° C. The resulting solution was stirred at 0° C. for 3 hours, then washed water. The aqueous phase was extracted with dichloromethane. The organic phase was washed with brine, dried over magnesium sulfate and condensed on a rotavap. The residue was recrystallized in hexane and ethyl acetate to provide 28.5 g (72% yield) of 1,5-difluoro-3-methoxy-2-nitrobenzene as an off-white powder. 1H NMR (400 MHz, DMSO) δ ppm 7.20 (m, 2H), 3.91 (s, 3H). The aqueous phase was extracted with dichloromethane The organic phase was washed with brine dried over magnesium sulfate and condensed on a rotavap The residue was recrystallized in hexane