tert-butyl 4-amino-2-fluorobenzoate

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

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

Procedure: tert-Butyl 2-fluoro-4-nitrobenzoate (24.2 g, 0.100 mol) was added to a warm (95° C.) solution of ammonium chloride (53.5 g, 1.00 mol), dissolved in ethanol (300 ml) and water (150 ml). Iron powder (325 mesh, 16.8 g, 0.300 mol) was added with stirring in small portions over ca. 1 h. The reaction mixture was stirred and heated at 95° C. for another 30 minutes and then filtered while still warm. The filter cake was washed thoroughly with excess ethanol. The filtrate and washings were diluted with water (1 L) and extracted with ether (3×150 ml). Combined ether extracts were washed with water and brine, dried (MgSO4), and evaporated to give the product as an off-white solid (21.1 g, 98%); mp 100-101° C. 1H NMR. The reaction mixture was stirred filtered while still warm The filter cake was washed thoroughly with excess ethanol The filtrate and washings were diluted with water (1 L) extracted with ether (3×150 ml) Combined ether extracts were washed with water and brine dried (MgSO4) evaporated

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

Procedure: Tert-butyl 2-fluoro-4-nitrobenzoate (24.2 g, 0.100 mol) was added to a warm (95° C.) solution of ammonium chloride (53.5 g, 1.00 mol), dissolved in ethanol (300 ml) and water (150 ml). Iron powder (325 mesh, 16.8 g, 0.300 mol) was added with stirring in small portions over ca. 1 h. The reaction mixture was stirred and heated at 95° C. for another 30 minutes and then filtered while still warm. The filter cake was washed thoroughly with excess ethanol. The filtrate and washings were diluted with water (1 L) and extracted with ether (3×150 ml). Combined ether extracts were washed with water and brine, dried (MgSO4), and evaporated to give the product as an off-white solid (21.1 g, 98%); mp 100-101° C. 1H NMR. The reaction mixture was stirred filtered while still warm The filter cake was washed thoroughly with excess ethanol The filtrate and washings were diluted with water (1 L) extracted with ether (3×150 ml) Combined ether extracts were washed with water and brine dried (MgSO4) evaporated

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

Procedure: tert-Butyl 2-fluoro-4-nitrobenzoate (24.2 g, 0.100 mol) was added to a warm (95° C.) solution of ammonium chloride (53.5 g, 1.00 mol), dissolved in ethanol (300 ml) and water (150 ml). Iron powder (325 mesh, 16.8 g, 0.300 mol) was added with stirring in small portions over ca. 1 h. The reaction mixture was stirred and heated at 95° C. for another 30 minutes and then filtered while still warm. The filter cake was washed thoroughly with excess ethanol. The filtrate and washings were diluted with water (1 L) and extracted with ether (3×150 ml). Combined ether extracts were washed with water and brine, dried (MgSO4), and evaporated to give the product as an off-white solid (21.1 g, 98%); mp 100-101° C. 1H NMR. The reaction mixture was stirred filtered while still warm The filter cake was washed thoroughly with excess ethanol The filtrate and washings were diluted with water (1 L) extracted with ether (3×150 ml) Combined ether extracts were washed with water and brine dried (MgSO4) evaporated

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

Procedure: tert-Butyl 2-fluoro-4-nitrobenzoate (24.2 g, 0.100 mol) was added to a warm (95° C.) solution of ammonium chloride (53.5 g, 1.00 mol), dissolved in ethanol (300 ml) and water (150 ml). Iron powder (325 mesh, 16.8 g, 0.300 mol) was added with stirring in small portions over ca. 1 h. The reaction mixture was stirred and heated at 95° C. for another 30 minutes and then filtered while still warm. The filter cake was washed thoroughly with excess ethanol. The filtrate and washings were diluted with water (1 L) and extracted with ether (3×150 ml). Combined ether extracts were washed with water and brine, dried (MgSO4), and evaporated to give the product as an off-white solid (21.1 g, 98%); mp 100-101° C. 1H NMR. The reaction mixture was stirred filtered while still warm The filter cake was washed thoroughly with excess ethanol The filtrate and washings were diluted with water (1 L) extracted with ether (3×150 ml) Combined ether extracts were washed with water and brine dried (MgSO4) evaporated

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

Procedure: 150 mg (0.43 mmol, 1.0 eq.) of 2-[4-(5-chloro-2-cyanophenyl)-5-methoxy-2-oxopyridin-1(2H)-yl]butanoic acid (racemate) and 152 mg (0.65 mmol, 1.5 eq.) of tert-butyl 2-fluoro-4-aminophenylcarboxylate were reacted according to General Method 5C. The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 20%-50% mixtures). Yield: 250 mg (purity 93%, 99% of theory) The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 20%-50% mixtures)

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

Procedure: A solution of 1.109 g (20.73 mmol, 10 eq.) of ammonium chloride in 6.25 ml of ethanol and 3.125 ml of water was heated to 95° C., and 500 mg (2.07 mmol) of tert-butyl 2-fluoro-4-nitrobenzoate were added. 347 mg (6.22 mmol, 3 eq.) of iron powder were added in small portions over 1 h. The reaction mixture was then stirred at 95° C. for 30 min, and the hot mixture was then filtered through kieselguhr. The filter cake was washed with ethanol and the filtrate was freed from ethanol under reduced pressure. The aqueous phase was extracted three times with in each case 20 ml of diethyl ether. The combined organic phases were washed with saturated aqueous sodium chloride solution, dried (sodium sulphate), filtered and concentrated under reduced pressure. The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 30%-50% mixtures). Yield: 280 mg (51% of theory). the hot mixture was then filtered through kieselguhr The filter cake was washed with ethanol The aqueous phase was extracted three times with in each case 20 ml of diethyl ether The combined organic phases were washed with saturated aqueous sodium chloride solution dried (sodium sulphate) filtered concentrated under reduced pressure The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 30%-50% mixtures)

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

Procedure: 150 mg (0.43 mmol, 1.0 eq.) of 2-[4-(5-chloro-2-cyanophenyl)-5-methoxy-2-oxopyridin-1(2H)-yl]butanoic acid (racemate) and 152 mg (0.65 mmol, 1.5 eq.) of tert-butyl 2-fluoro-4-aminophenylcarboxylate were reacted according to General Method 5C. The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 20%-50% mixtures). Yield: 250 mg (purity 93%, 99% of theory) The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 20%-50% mixtures)

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

Procedure: A solution of 1.109 g (20.73 mmol, 10 eq.) of ammonium chloride in 6.25 ml of ethanol and 3.125 ml of water was heated to 95° C., and 500 mg (2.07 mmol) of tert-butyl 2-fluoro-4-nitrobenzoate were added. 347 mg (6.22 mmol, 3 eq.) of iron powder were added in small portions over 1 h. The reaction mixture was then stirred at 95° C. for 30 min, and the hot mixture was then filtered through kieselguhr. The filter cake was washed with ethanol and the filtrate was freed from ethanol under reduced pressure. The aqueous phase was extracted three times with in each case 20 ml of diethyl ether. The combined organic phases were washed with saturated aqueous sodium chloride solution, dried (sodium sulphate), filtered and concentrated under reduced pressure. The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 30%-50% mixtures). Yield: 280 mg (51% of theory). the hot mixture was then filtered through kieselguhr The filter cake was washed with ethanol The aqueous phase was extracted three times with in each case 20 ml of diethyl ether The combined organic phases were washed with saturated aqueous sodium chloride solution dried (sodium sulphate) filtered concentrated under reduced pressure The crude product was purified by normal phase chromatography (mobile phase: cyclohexane/ethyl acetate 30%-50% mixtures)

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

Procedure: To a solution of N-chlorosuccinimide (950 mg, 7.1 mmol) in N,N-dimethylformamide (25 mL) was added dropwise a solution of tert-butyl 4-amino-2-fluorobenzoate (1.5 g, 7.1 mmol) in N,N-dimethylformamide (22 mL). The resulting mixture was stirred at room temperature for 3 hours and then brine solution (80 mL) and ethyl acetate (100 mL) were added. The organic phase was collected and washed three times with brine (50 mL). Combined organic phases were dried on magnesium sulphate and evaporated under reduced pressure. Purification of the residue via silica gel column chromatography (4% EtOAc in iso-hexane) gave tert-butyl 4-amino-5-chloro-2-fluorobenzoate (400 mg, 23%, 1H NMR (400 MHz, DMSO-d6): δ 7.63 (d, J=7.6 Hz, 1H), 6.55 (d, J=13.2 Hz, 1H), 6.46 (brs, 2H), 1.52 (s, 9H)) and tert-butyl 4-amino-3-chloro-2-fluorobenzoate (490 mg, 28%, 1H NMR (400 MHz, DMSO-d6): δ 7.52 (t, J=8.4 Hz, 1H), 6.64 (dd, J=1.2 Hz and J=8.4 Hz, 1H), 6.50 (brs, 2H), 1.53 (s, 9H)) both as a white solid. The organic phase was collected washed three times with brine (50 mL) Combined organic phases were dried on magnesium sulphate evaporated under reduced pressure Purification of the residue via silica gel column chromatography (4% EtOAc in iso-hexane)

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

Procedure: To a solution of N-chlorosuccinimide (950 mg, 7.1 mmol) in N,N-dimethylformamide (25 mL) was added dropwise a solution of tert-butyl 4-amino-2-fluorobenzoate (1.5 g, 7.1 mmol) in N,N-dimethylformamide (22 mL). The resulting mixture was stirred at room temperature for 3 hours and then brine solution (80 mL) and ethyl acetate (100 mL) were added. The organic phase was collected and washed three times with brine (50 mL). Combined organic phases were dried on magnesium sulphate and evaporated under reduced pressure. Purification of the residue via silica gel column chromatography (4% EtOAc in iso-hexane) gave tert-butyl 4-amino-5-chloro-2-fluorobenzoate (400 mg, 23%, 1H NMR (400 MHz, DMSO-d6): δ 7.63 (d, J=7.6 Hz, 1H), 6.55 (d, J=13.2 Hz, 1H), 6.46 (brs, 2H), 1.52 (s, 9H)) and tert-butyl 4-amino-3-chloro-2-fluorobenzoate (490 mg, 28%, 1H NMR (400 MHz, DMSO-d6): δ 7.52 (t, J=8.4 Hz, 1H), 6.64 (dd, J=1.2 Hz and J=8.4 Hz, 1H), 6.50 (brs, 2H), 1.53 (s, 9H)) both as a white solid. The organic phase was collected washed three times with brine (50 mL) Combined organic phases were dried on magnesium sulphate evaporated under reduced pressure Purification of the residue via silica gel column chromatography (4% EtOAc in iso-hexane)

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

Procedure: Tert-butyl 2-fluoro-4-nitrobenzoate (24.2 g, 0.100 mol) was added to a warm (95° C.) solution of ammonium chloride (53.5 g, 1.00 mol), dissolved in ethanol (300 ml) and water (150 ml). Iron powder (325 mesh, 16.8 g, 0.300 mol) was added with stirring in small portions over about 1 h. The reaction mixture was stirred and heated at 95° C. for another 30 minutes and then filtered while still warm. The filter cake was washed thoroughly with excess ethanol. The filtrate and washings were diluted with water (1 L) and extracted with ether (3×150 ml). Combined ether extracts were washed with water and brine, dried (MgSO4), and evaporated to give the product as an off-white solid (21.1 g, 98%); mp 100-101° C. The reaction mixture was stirred filtered while still warm The filter cake was washed thoroughly with excess ethanol The filtrate and washings were diluted with water (1 L) extracted with ether (3×150 ml) Combined ether extracts were washed with water and brine dried (MgSO4) evaporated