2-amino-4-bromo-5-fluorophenol

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

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a 0° C. mixture of 2-amino-4-bromo-5-fluorophenol (38.0 g, crude from previous step) and K2CO3 (76.0 g, 553 mmol) in DMF (100 mL) was added 2-chloroacetyl chloride (23.0 g, 15.3 mL, 203 mmol) drop-wise. The reaction mixture was heated at 80° C. overnight then cooled to ambient temperature and poured into water (300 mL). The precipitate was collected by filtration, washed with water and dried to give 6-bromo-7-fluoro-4H-benzo[1,4]oxazin-3-one (41.0 g, 90%). 1H NMR (DMSO-d6, 400 MHz): δ 7.13 (m, 2H), 4.62 (s, 2H). The amide proton was not observed. then cooled to ambient temperature The precipitate was collected by filtration washed with water dried

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

Procedure: To a solution of 4-bromo-5-fluoro-2-nitrophenol (40.0 g, 169 mmol) in MeOH (250 mL) and THF (250 mL) was added zinc powder (91.0 g, 1700 mmol) and ammonium chloride (111.0 g, 1700 mmol) and the reaction mixture was stirred at ambient temperature overnight. The reaction mixture was filtered and the filtrate was concentrated in vacuo. The residue was washed with cold water to give 2-amino-4-bromo-5-fluorophenol (38.0 g, crude) which was used in the next step directly without further purification. 1H NMR (DMSO-d6, 400 MHz): δ 9.82 (br s, 1H), δ 6.76 (d, J=7.2 Hz, 1H), 6.60 (d, J=10.0 Hz, 1H), 4.65 (br s, 2H). The reaction mixture was filtered the filtrate was concentrated in vacuo The residue was washed with cold water

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

Procedure: To a solution of 4-bromo-5-fluoro-2-nitrophenol (40.0 g, 169 mmol) in MeOH (250 mL) and THF (250 mL) was added zinc powder (91.0 g, 1700 mmol) and ammonium chloride (111.0 g, 1700 mmol) and the reaction mixture was stirred at ambient temperature overnight. The reaction mixture was filtered and the filtrate was concentrated in vacuo. The residue was washed with cold water to give 2-amino-4-bromo-5-fluorophenol (38.0 g, crude) which was used in the next step directly without further purification. 1H NMR (DMSO-d6, 400 MHz): δ 9.82 (br s, 1H), δ 6.76 (d, J=7.2 Hz, 1H), 6.60 (d, J=10.0 Hz, 1H), 4.65 (br s, 2H). The reaction mixture was filtered the filtrate was concentrated in vacuo The residue was washed with cold water

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

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

Procedure: A solution of 2-amino-4-bromo-5-fluorophenol (10.1 g, 49 mmol), 2,4-difluorobenzaldehyde (5.36 mL, 49 mmol) and p-toluenesulfonic acid (100 mg, 0.52 mmol) in toluene (250 mL) was heated to reflux in a Dean-Stark apparatus for 0.5 h and then allowed to cool to ambient temperature. After adding triethylamine (1 mL) the reaction mixture was concentrated under reduced pressure to give the crude compound which was used without further purification. (16.1 g, 99%). 1H-NMR (400 MHz, CDCl3) 6.83 (d, J=10.2, 1H), 6.93 (m, 1H), 7.01 (m, 1H), 7.49 (d, J=7.6, 1H), 8.13 (m, 1H), 8.85 (s, 1H). to reflux in a Dean-Stark apparatus for 0.5 h was concentrated under reduced pressure

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

Procedure: A suspension of Na2S2O4 (51.6 g, 296 mmol) in water (122 mL) was added slowly to a refluxed mixture of 4-bromo-5-fluoro-2-nitrophenol (14 g, 59.3 mmol) in ethanol (1000 mL). The resulting mixture was refluxed for 1 h. After cooling down the salts were filtered off and the filtrate was partially concentrated. Brine was added, extracted with diethyl ether, the extract dried and concentrated to give the crude title compound which was used without further purification (9.2 g, 75%). 1H-NMR (400 MHz, DMSO) 4.65 (br, 2H), 6.60 (d, J=11.3, 1H), 6.76 (d, J=7.8, 1H), 9.80 (br, 1H). The resulting mixture was refluxed for 1 h After cooling down the salts were filtered off the filtrate was partially concentrated Brine was added extracted with diethyl ether the extract dried concentrated

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A flask was charged with 2-amino-4-bromo-5-fluorophenol (3.3 g, 18.84 mmol) and THF (200 mL), and CDI (3.05 g, 18.84 mmol) was added. The mixture was heated to 60° C. for 2 h. The mixture was diluted with EtOAc and washed with 1N HCl in water. The organic phase was dried over Na2SO4 and concentrated to give 5-bromo-6-fluorobenzo[d]oxazol-2(3H)-one. 1H NMR (400 MHz, DMSO-d6) δppm 7.38 (d, J=6.06 Hz, 1H) 7.56 (d, J=8.34 Hz, 1H) 11.88 (br. s., 1H). was added washed with 1N HCl in water The organic phase was dried over Na2SO4 concentrated

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Tin(II) chloride dihydrate (16.83 g, 74.6 mmol) was added to a solution of 4-bromo-5-fluoro-2-nitrophenol (4.4 g, 18.64 mmol) in ethanol (180 mL). The mixture was flushed with nitrogen and heated to 85° C. (oil bath temperature) for 1 day. The mixture was diluted with ethyl acetate (500 mL), saturated aqueous sodium bicarbonate (200 mL) was added with vigorous stirring. The mixture was filtered through celite and the celite pad was repeatedly washed with ethyl acetate. The two phases were separated and the organic phase was washed with brine. The combined aqueous phase was extracted with ethyl acetate. The combined organic phase was dried over MgSO4, filtered and concentrated to give 2-amino-4-bromo-5-fluorophenol. 1H NMR (400 MHz, DMSO-d6) δ ppm 4.61 (br. s., 2H) 6.60 (d, J=10.11 Hz, 1H) 6.76 (d, J=7.33 Hz, 1H) 9.69 (br. s., 1 H). The mixture was flushed with nitrogen The mixture was diluted with ethyl acetate (500 mL), saturated aqueous sodium bicarbonate (200 mL) was added with vigorous stirring The mixture was filtered through celite the celite pad was repeatedly washed with ethyl acetate The two phases were separated the organic phase was washed with brine The combined aqueous phase was extracted with ethyl acetate The combined organic phase was dried over MgSO4 filtered concentrated

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a 0° C. mixture of 2-amino-4-bromo-5-fluorophenol (38.0 g, crude from previous step) and K2CO3 (76.0 g, 553 mmol) in DMF (100 mL) was added 2-chloroacetyl chloride (23.0 g, 15.3 mL, 203 mmol) drop-wise. The reaction mixture was heated at 80° C. overnight then cooled to ambient temperature and poured into water (300 mL). The precipitate was collected by filtration, washed with water and dried to give 6-bromo-7-fluoro-4H-benzo[1,4]oxazin-3-one (41.0 g, 90%). 1H NMR (DMSO-d6, 400 MHz): δ 7.13 (m, 2H), 4.62 (s, 2H). The amide proton was not observed. then cooled to ambient temperature The precipitate was collected by filtration washed with water dried

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

Procedure: To a solution of 4-bromo-5-fluoro-2-nitrophenol (40.0 g, 169 mmol) in MeOH (250 mL) and THF (250 mL) was added zinc powder (91.0 g, 1700 mmol) and ammonium chloride (111.0 g, 1700 mmol) and the reaction mixture was stirred at ambient temperature overnight. The reaction mixture was filtered and the filtrate was concentrated in vacuo. The residue was washed with cold water to give 2-amino-4-bromo-5-fluorophenol (38.0 g, crude) which was used in the next step directly without further purification. 1H NMR (DMSO-d6, 400 MHz): δ 9.82 (br s, 1H), δ 6.76 (d, J=7.2 Hz, 1H), 6.60 (d, J=10.0 Hz, 1H), 4.65 (br s, 2H). The reaction mixture was filtered the filtrate was concentrated in vacuo The residue was washed with cold water