4-Bromo-2,5-difluorobenzaldehyde

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

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

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

Procedure: Using analogous reaction condition and reagents as described in Example 25 for the preparation of I-25a above, 4-bromo-2,5-difluoro-benzaldehyde (I-27a: 1.71 g, 7.73 mmol) was reacted with TEA (1.4 mL, 10.05 mmol), mercapto-acetic acid methyl ester (920 mg, 8.51 mmol) and acetonitrile (50 mL) to afford crude product. Purification by column chromatography on silica gel (5% ethyl acetate in hexane) afforded 2.3 g of the product (Yield 64%). to afford crude product Purification by column chromatography on silica gel (5% ethyl acetate in hexane)

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

Procedure: n-Butyl lithium (3.6 ml, 7.7 mmol) was added drop wise to a solution of 1,4-dibromo-2,5-difluoro-benzene (2 g, 7.35 mmol) in dry ether at −78° C. under nitrogen atmosphere and the resulting mixture was stirred at −78° C. for 30 minutes. This was followed by the addition of DMF (0.85 ml, 11.03 mmol) in dry THF. The resultant was stirred at room temperature for 1 hour. The reaction was monitored by TLC (5% ethyl acetate in hexane). The reaction mixture was partitioned between ethyl acetate and saturated ammonium chloride. The organic layer was concentrated and purified by column chromatography on silica gel (2% ethyl acetate in hexane) to afford 600 mg of the product (37% yield). The resultant was stirred at room temperature for 1 hour The reaction mixture was partitioned between ethyl acetate and saturated ammonium chloride The organic layer was concentrated purified by column chromatography on silica gel (2% ethyl acetate in hexane)

Conditions: temp:95.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 4-bromo-2,5-difluorobenzaldehyde (15.0 g) in triethylamine formiate (80 mL) at room temperature was added 2,2-dimethyl-1,3-dioxane-4,6-dione (9.77 g). After being stirred for 1 h, the mixture was heated at 95° C. with stirring for 15 hours. After cooling down, ice water was added. The mixture was adjusted to pH ˜1 with HCl (6 M) and then extracted with ethyl acetate (200 mL×3). The organic phase was washed with brine (50 mL) and dried over Na2SO4. The solvent was removed under reduced pressure and the residue was purified by silica gel column chromatography eluting with DCM/petroleum ether (7:1) to give the subtitle compound as a white solid. MS ESI+: m/z=263 [M+H]+. with stirring for 15 hours After cooling down extracted with ethyl acetate (200 mL×3) The organic phase was washed with brine (50 mL) dried over Na2SO4 The solvent was removed under reduced pressure the residue was purified by silica gel column chromatography eluting with DCM/petroleum ether (7:1)

Conditions: temp:95.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 4-bromo-2,5-difluorobenzaldehyde (15.0 g) in triethylamine formiate (80 mL) at room temperature was added 2,2-dimethyl-1,3-dioxane-4,6-dione (9.77 g). After being stirred for 1 h, the mixture was heated at 95° C. with stirring for 15 hours. After cooling down, ice water was added. The mixture was adjusted to pH ˜1 with HCl (6 M) and then extracted with ethyl acetate (200 mL×3). The organic phase was washed with brine (50 mL) and dried over Na2SO4. The solvent was removed under reduced pressure and the residue was purified by silica gel column chromatography eluting with DCM/petroleum ether (7:1) to give the subtitle compound as a white solid. MS ESI+: m/z=263 [M+H]+. with stirring for 15 hours After cooling down extracted with ethyl acetate (200 mL×3) The organic phase was washed with brine (50 mL) dried over Na2SO4 The solvent was removed under reduced pressure the residue was purified by silica gel column chromatography eluting with DCM/petroleum ether (7:1)

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

Procedure: Using analogous reaction condition and reagents as described in Example 25 for the preparation of I-25a above, 4-bromo-2,5-difluoro-benzaldehyde (I-27a: 1.71 g, 7.73 mmol) was reacted with TEA (1.4 mL, 10.05 mmol), mercapto-acetic acid methyl ester (920 mg, 8.51 mmol) and acetonitrile (50 mL) to afford crude product. Purification by column chromatography on silica gel (5% ethyl acetate in hexane) afforded 2.3 g of the product (Yield 64%). to afford crude product Purification by column chromatography on silica gel (5% ethyl acetate in hexane)

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

Procedure: n-Butyl lithium (3.6 ml, 7.7 mmol) was added drop wise to a solution of 1,4-dibromo-2,5-difluoro-benzene (2 g, 7.35 mmol) in dry ether at −78° C. under nitrogen atmosphere and the resulting mixture was stirred at −78° C. for 30 minutes. This was followed by the addition of DMF (0.85 ml, 11.03 mmol) in dry THF. The resultant was stirred at room temperature for 1 hour. The reaction was monitored by TLC (5% ethyl acetate in hexane). The reaction mixture was partitioned between ethyl acetate and saturated ammonium chloride. The organic layer was concentrated and purified by column chromatography on silica gel (2% ethyl acetate in hexane) to afford 600 mg of the product (37% yield). The resultant was stirred at room temperature for 1 hour The reaction mixture was partitioned between ethyl acetate and saturated ammonium chloride The organic layer was concentrated purified by column chromatography on silica gel (2% ethyl acetate in hexane)

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

Procedure: A solution of 4-bromo-2,5-difluorobenzaldehyde (7.0 g, 31.67 mmol), hydroxyl amine hydrochloride (2.42 g, 34.84 mmol) in pyridine (35 mL) and ethanol (35 mL) was stirred at room temperature for 30 min. The reaction mixture was diluted with saturated ammonium chloride solution and extracted with ethyl acetate. The organic phase was washed with saturated brine solution, dried (Na2SO4), filtered, and concentrated under reduced pressure. The crude product was purified by flash chromatography (SiO2, eluting with 5-100% ethyl acetate in hexanes) to provide the title compound as a yellow solid (4.0 g, 53%): ESIMS m/z 238 [(M+2H)+]. extracted with ethyl acetate The organic phase was washed with saturated brine solution dried (Na2SO4) filtered concentrated under reduced pressure The crude product was purified by flash chromatography (SiO2, eluting with 5-100% ethyl acetate in hexanes)

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

Procedure: To a solution of 2,5-dibromo-1,4-difluorobenzene (10.0 g, 36.77 mmol) in diethyl ether (150 mL) at −78° C. was added n-butyl lithium (2.5 M in Hexanes, 14.86 mL, 37.15 mmol) dropwise under nitrogen. The reaction mixture was stirred at −78° C. for 30 min. Dry DMF (3.13 mL, 40.46 mmol) in diethyl ether (10 mL) was added dropwise and reaction was slowly warmed to room temperature over 2 h. The reaction was quenched with aqueous saturated ammonium chloride solution (25 mL) and extracted with diethyl ether. The organic phase was washed with saturated brine solution, dried (Na2SO4), filtered, and concentrated under reduced pressure (Note: Product is highly volatile). The crude product was purified by flash chromatography (SiO2, eluting with 2-20% ethyl acetate in hexanes) to provide the title compound as a pale yellow solid (7.0 g, 86%): 1H NMR (400 MHz, CDCl3): δ 7.50 (dd, J=5.08, 8.92 Hz, 1H), 7.62 (dd, J=5.80, 7.68 Hz, 1H), 10.30 (d, J=2.76 Hz, 1H). reaction was slowly warmed to room temperature over 2 h The reaction was quenched with aqueous saturated ammonium chloride solution (25 mL) extracted with diethyl ether The organic phase was washed with saturated brine solution dried (Na2SO4) filtered concentrated under reduced pressure ( The crude product was purified by flash chromatography (SiO2, eluting with 2-20% ethyl acetate in hexanes)

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

Procedure: To a solution of 2,5-dibromo-1,4-difluorobenzene (10.0 g, 36.77 mmol) in diethyl ether (150 mL) at −78° C. was added n-butyl lithium (2.5 M in Hexanes, 14.86 mL, 37.15 mmol) dropwise under nitrogen. The reaction mixture was stirred at −78° C. for 30 min. Dry DMF (3.13 mL, 40.46 mmol) in diethyl ether (10 mL) was added dropwise and reaction was slowly warmed to room temperature over 2 h. The reaction was quenched with aqueous saturated ammonium chloride solution (25 mL) and extracted with diethyl ether. The organic phase was washed with saturated brine solution, dried (Na2SO4), filtered, and concentrated under reduced pressure (Note: Product is highly volatile). The crude product was purified by flash chromatography (SiO2, eluting with 2-20% ethyl acetate in hexanes) to provide the title compound as a pale yellow solid (7.0 g, 86%): 1H NMR (400 MHz, CDCl3): δ 7.50 (dd, J=5.08, 8.92 Hz, 1H), 7.62 (dd, J=5.80, 7.68 Hz, 1H), 10.30 (d, J=2.76 Hz, 1H). reaction was slowly warmed to room temperature over 2 h The reaction was quenched with aqueous saturated ammonium chloride solution (25 mL) extracted with diethyl ether The organic phase was washed with saturated brine solution dried (Na2SO4) filtered concentrated under reduced pressure ( The crude product was purified by flash chromatography (SiO2, eluting with 2-20% ethyl acetate in hexanes)

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

Procedure: To a round bottom flask with stir bar was added 4-bromo-2,5-difluorobenzaldehyde (5.3 g, 24.0 mmol), (R)-2-methylpropane-2-sulfinamide (3.2 g, 26.4 mmol) and DCE (80 mL). To this mixture was then added copper (II) sulfate (5.74 g, 36.0 mmol). The reaction mixture was heated in a preheated oil bath at 60° C. for 18 hours. The reaction mixture was filtered through a pad celite, washing the solids with DCE. The filtrate was concentrated to afford a viscous green oil of (R,E)-N-(4-bromo-2,5-difluorobenzylidene)-2-methylpropane-2-sulfinamide (7.2 g, 22.2 mmol, 93% yield). Material was taken onto next step without further purification. LCMS m/z 326.0 (M+H)+, Rt 1.04 min. The reaction mixture was filtered through a pad celite washing the solids with DCE The filtrate was concentrated