ethyl 2,3,4,6-tetrafluorobenzoate

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

Procedure: A solution of 2,3,4,6-tetrafluorobenzoic acid ethyl ester (Example 1b, 5.1 g, 22.9 mmol), triethylamine (22 mL, 157 mmol), and (S)-pyrrolidin-3-ylcarbamic acid tert-butyl ester (5.2 g, 27.9 mmol) in acetonitrile (60 mL) is stirred at room temperature for 64 hours. The mixture is concentrated in vacuo and the residue dissolved in chloroform, washed with NaHCO3 and then brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford a solid. The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes) to afford the title compound (6.21 g). 1H NMR (CDCl3): δ 6.07 (ddd, 1H), 4.78-4.63 (bd, 1H), 4.49-4.22 (m, 3H), 3.80-3.68 (m, 1H), 3.66-3.28 (m, 3H), 2.33-2.13 (m, 1H), 2.04-1.83 (m, 1H), 1.45 (s, 9H), 1.36 (t, 3H). The mixture is concentrated in vacuo the residue dissolved in chloroform washed with NaHCO3 brine, dried over Na2SO4 filtered concentrated under vacuum to afford a solid The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes)

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

Procedure: 2,3,4,6-Tetrafluorobenzoic acid (4.8 g, 24.7 mmol) in dichloromethane (80 mL) is cooled to 0° C. under a nitrogen atmosphere and treated with oxalyl chloride (11.2 mL, 128 mmol) followed by anhydrous N,N-dimethylformamide (2 drops). The mixture is warmed to room temperature and stirred for 2 hours. The solution is co-evaporated with benzene to yield an oil that is taken up in dichloromethane (80 mL), cooled to 0° C. under an inert atmosphere, and treated with anhydrous ethanol (15 mL, 258 mmol). After 5 hours at room temperature, the solution is poured into saturated NaHCO3 and extracted with chloroform. The organic phase is washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to provide the title compound (3.3 g). This material is used without further purification. 1H NMR (CDCl3): δ 6.93-6.75 (m, 1H), 4.42 (q, 2H), 1.39 (t, 3H). to yield an oil that cooled to 0° C. under an inert atmosphere After 5 hours at room temperature extracted with chloroform The organic phase is washed with brine dried over Na2SO4 filtered concentrated under vacuum

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

Procedure: A solution of 2,3,4,6-tetrafluorobenzoic acid ethyl ester (Example 1b, 5.1 g, 22.9 mmol), triethylamine (22 mL, 157 mmol), and (S)-pyrrolidin-3-ylcarbamic acid tert-butyl ester (5.2 g, 27.9 mmol) in acetonitrile (60 mL) is stirred at room temperature for 64 hours. The mixture is concentrated in vacuo and the residue dissolved in chloroform, washed with NaHCO3 and then brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford a solid. The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes) to afford the title compound (6.21 g). 1H NMR (CDCl3): δ 6.07 (ddd, 1H), 4.78–4.63 (bd, 1H), 4.49–4.22 (m, 3H), 3.80–3.68 (m, 1H), 3.66–3.28 (m, 3H), 2.33–2.13 (m, 1H), 2.04–1.83 (m, 1H), 1.45 (s, 9H), 1.36 (t, 3H). The mixture is concentrated in vacuo the residue dissolved in chloroform washed with NaHCO3 brine, dried over Na2SO4 filtered concentrated under vacuum to afford a solid The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes)

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

Procedure: 2,3,4,6-Tetrafluorobenzoic acid (4.8 g, 24.7 mmol) in dichloromethane (80 mL) is cooled to 0° C. under a nitrogen atmosphere and treated with oxalyl chloride (11.2 mL, 128 mmol) followed by anhydrous N,N-dimethylformamide (2 drops). The mixture is warmed to room temperature and stirred for 2 hours. The solution is co-evaporated with benzene to yield an oil that is taken up in dichloromethane (80 mL), cooled to 0° C. under an inert atmosphere, and treated with anhydrous ethanol (15 mL, 258 mmol). After 5 hours at room temperature, the solution is poured into saturated NaHCO3 and extracted with chloroform. The organic phase is washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to provide the title compound (3.3 g). This material is used without further purification. 1H NMR (CDCl3): δ 6.93–6.75 (m, 1H), 4.42 (q, 2H), 1.39 (t, 3H). to yield an oil that cooled to 0° C. under an inert atmosphere After 5 hours at room temperature extracted with chloroform The organic phase is washed with brine dried over Na2SO4 filtered concentrated under vacuum

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

Procedure: A solution of 2,3,4,6-tetrafluorobenzoic acid ethyl ester (Example 1b, 5.1 g, 22.9 mmol), triethylamine (22 mL, 157 mmol), and (S)-pyrrolidin-3-ylcarbamic acid tert-butyl ester (5.2 g, 27.9 mmol) in acetonitrile (60 mL) is stirred at room temperature for 64 hours. The mixture is concentrated in vacuo and the residue dissolved in chloroform, washed with NaHCO3 and then brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford a solid. The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes) to afford the title compound (6.21 g). 1H NMR (CDCl3): δ 6.07 (ddd, 1H), 4.78–4.63 (bd, 1H), 4.49–4.22 (m, 3H), 3.80–3.68 (m, 1H), 3.66–3.28 (m, 3H), 2.33–2.13 (m, 1H), 2.04–1.83 (m, 1H), 1.45 (s, 9H), 1.36 (t, 3H). The mixture is concentrated in vacuo the residue dissolved in chloroform washed with NaHCO3 brine, dried over Na2SO4 filtered concentrated under vacuum to afford a solid The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes)

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

Procedure: 2,3,4,6-Tetrafluorobenzoic acid (4.8 g, 24.7 mmol) in dichloromethane (80 mL) is cooled to 0° C. under a nitrogen atmosphere and treated with oxalyl chloride (11.2 mL, 128 mmol) followed by anhydrous N,N-dimethylformamide (2 drops). The mixture is warmed to room temperature and stirred for 2 hours. The solution is co-evaporated with benzene to yield an oil that is taken up in dichloromethane (80 mL), cooled to 0° C. under an inert atmosphere, and treated with anhydrous ethanol (15 mL, 258 mmol). After 5 hours at room temperature, the solution is poured into saturated NaHCO3 and extracted with chloroform. The organic phase is washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to provide the title compound (3.3 g). This material is used without further purification. 1H NMR (CDCl3): δ 6.93–6.75 (m, 1H), 4.42 (q, 2H), 1.39 (t, 3H). to yield an oil that cooled to 0° C. under an inert atmosphere After 5 hours at room temperature extracted with chloroform The organic phase is washed with brine dried over Na2SO4 filtered concentrated under vacuum

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

Procedure: A solution of 2,3,4,6-tetrafluorobenzoic acid ethyl ester (Example 1b, 5.1 g, 22.9 mmol), triethylamine (22 mL, 157 mmol), and (S)-pyrrolidin-3-ylcarbamic acid tert-butyl ester (5.2 g, 27.9 mmol) in acetonitrile (60 mL) is stirred at room temperature for 64 hours. The mixture is concentrated in vacuo and the residue dissolved in chloroform, washed with NaHCO3 and then brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford a solid. The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes) to afford the title compound (6.21 g). 1H NMR (CDCl3): δ 6.07 (ddd, 1H), 4.78-4.63 (bd, 1H), 4.49-4.22 (m, 3H), 3.80-3.68 (m, 1H), 3.66-3.28 (m, 3H), 2.33-2.13 (m, 1H), 2.04-1.83 (m, 1H), 1.45 (s, 9H), 1.36 (t, 3H). The mixture is concentrated in vacuo the residue dissolved in chloroform washed with NaHCO3 brine, dried over Na2SO4 filtered concentrated under vacuum to afford a solid The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes)

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

Procedure: 2,3,4,6-Tetrafluorobenzoic acid (4.8 g, 24.7 mmol) in dichloromethane (80 mL) is cooled to 0° C. under a nitrogen atmosphere and treated with oxalyl chloride (11.2 mL, 128 mmol) followed by anhydrous N,N-dimethylformamide (2 drops). The mixture is warmed to room temperature and stirred for 2 hours. The solution is co-evaporated with benzene to yield an oil that is taken up in dichloromethane (80 mL), cooled to 0° C. under an inert atmosphere, and treated with anhydrous ethanol (15 mL, 258 mmol). After 5 hours at room temperature, the solution is poured into saturated NaHCO3 and extracted with chloroform. The organic phase is washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to provide the title compound (3.3 g). This material is used without further purification. 1H NMR (CDCl3): δ 6.93-6.75 (m, 1H), 4.42 (q, 2H), 1.39 (t, 3H). to yield an oil that cooled to 0° C. under an inert atmosphere After 5 hours at room temperature extracted with chloroform The organic phase is washed with brine dried over Na2SO4 filtered concentrated under vacuum

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

Procedure: A solution of 2,3,4,6-tetrafluorobenzoic acid ethyl ester (Example 1b, 5.1 g, 22.9 mmol), triethylamine (22 mL, 157 mmol), and (S)-pyrrolidin-3-ylcarbamic acid tert-butyl ester (5.2 g, 27.9 mmol) in acetonitrile (60 mL) is stirred at room temperature for 64 hours. The mixture is concentrated in vacuo and the residue dissolved in chloroform, washed with NaHCO3 and then brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford a solid. The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes) to afford the title compound (6.21 g). 1H NMR (CDCl3): δ 6.07 (ddd, 1H), 4.78–4.63 (bd, 1H), 4.49–4.22 (m, 3H), 3.80–3.68 (m, 1H), 3.66–3.28 (m, 3H), 2.33–2.13 (m, 1H), 2.04–1.83 (m, 1H), 1.45 (s, 9H), 1.36 (t, 3H). The mixture is concentrated in vacuo the residue dissolved in chloroform washed with NaHCO3 brine, dried over Na2SO4 filtered concentrated under vacuum to afford a solid The solid is purified by column chromatography (1:1:7 ethyl acetate/chloroform/hexanes)

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

Procedure: 2,3,4,6-Tetrafluorobenzoic acid (4.8 g, 24.7 mmol) in dichloromethane (80 mL) is cooled to 0° C. under a nitrogen atmosphere and treated with oxalyl chloride (11.2 mL, 128 mmol) followed by anhydrous N,N-dimethylformamide (2 drops). The mixture is warmed to room temperature and stirred for 2 hours. The solution is co-evaporated with benzene to yield an oil that is taken up in dichloromethane (80 mL), cooled to 0° C. under an inert atmosphere, and treated with anhydrous ethanol (15 mL, 258 mmol). After 5 hours at room temperature, the solution is poured into saturated NaHCO3 and extracted with chloroform. The organic phase is washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to provide the title compound (3.3 g). This material is used without further purification. 1H NMR (CDCl3): δ 6.93–6.75 (m, 1H), 4.42 (q, 2H), 1.39 (t, 3H). to yield an oil that cooled to 0° C. under an inert atmosphere After 5 hours at room temperature extracted with chloroform The organic phase is washed with brine dried over Na2SO4 filtered concentrated under vacuum