5,6-difluoro-1H-indole

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

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

Procedure: To a solution of 5,6-difluoro-1H-indole (1.0 g) in N,N-dimethylformamide (10 mL) was added phosphoryl chloride (1.2 g) at 0° C., and this mixture was stirred at room temperature for 4 hours. To this mixture was added 2 mol/L aqueous sodium hydroxide solution (5 mL), and this resulting mixture was stirred at 70° C. for 0.5 hours. After cooling to ambient temperature, this mixture was poured into 1 mol/L hydrochloric acid and the resulting mixture was extracted with ethyl acetate. The organic layer was washed with water and brine, and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure to give the title compound (1.1 g). this resulting mixture was stirred at 70° C. for 0.5 hours After cooling to ambient temperature the resulting mixture was extracted with ethyl acetate The organic layer was washed with water and brine dried over anhydrous magnesium sulfate The solvent was removed under reduced pressure

Conditions: temp:-75.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1.25 ml (2 mmol) of a 1.6 M butyl lithium solution in hexane were diluted with 4 ml THF at −78° C. under nitrogen. 224 mg (2 mmol) of potassium-tert-butylate and then 156 mg (1 mmol) of 5,6-difluoro-1H-indol were added. The reaction was exothermal and an orange solution was obtained, which was stirred for 2 h at −75° C. Solid carbon dioxide was added at that temperature and the reaction mixture was allowed to warm to rt within 30 min. Water was added and the reaction mixture was extracted three times with diethyl ether. The aqueous layer was acidified with 1N aqueous HCl solution and extracted three times with diethyl ether. The combined organic layers were washed with saturated aqueous NaCl solution, dried over sodium sulfate, filtered and the solvent was evaporated. The residue was stirred with n-hexane and a trace of diethyl ether for 15 min and filtered to yield 100 mg (51%) product as a yellow solid. 1H NMR (DMSO-d6, 300 MHz): 13.6 (br, 1H), 11.2 (br, 1H), 7.85 (dd, 1H), 7.42 (s, 1H), 6.53 (s, 1H). an orange solution was obtained to warm to rt within 30 min the reaction mixture was extracted three times with diethyl ether extracted three times with diethyl ether The combined organic layers were washed with saturated aqueous NaCl solution dried over sodium sulfate filtered the solvent was evaporated The residue was stirred with n-hexane a trace of diethyl ether for 15 min filtered

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

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

Procedure: A suspension of [2-(4,5-difluoro-2-nitro-phenyl)-vinyl]-dimethyl-amine (7.0 g, 30.7 mmol) and 10% palladium on charcoal (1.4 g) in methyl alcohol was hydrogenated in a Parr apparatus at 50 psi for 2 h and then filtered through Celite. The filtrate was concentrated in vacuo and the crude product purified by silica gel column chromatography (hexanes/ethyl acetate, 8:2) to afford 5,6-difluoroindole (1.28 g, 28%) as a yellow solid. 1H-NMR δ (400 MHz, CDCl3) 8.10 (1H, br s), 7.36 (1H, dd, J=10.7, 7.8 Hz), 7.22 (1H, t, J=2.8 Hz), 7.17 (1H, dd, J=7.4, 3.1 Hz), 6.50 (1H, m). filtered through Celite The filtrate was concentrated in vacuo the crude product purified by silica gel column chromatography (hexanes/ethyl acetate, 8:2)

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

Procedure: A suspension of [2-(4,5-difluoro-2-nitro-phenyl)-vinyl]-dimethyl-amine (7.0 g, 30.7 mmol) and 10% palladium on charcoal (1.4 g) in methyl alcohol was hydrogenated in a Parr apparatus at 50 psi for 2 h and then filtered through Celite. The filtrate was concentrated in vacuo and the crude product purified by silica gel column chromatography (hexanes/ethyl acetate, 8:2) to afford 5,6-difluoroindole (1.28 g, 28%) as a yellow solid. 1H-NMR δ (400 MHz, CDCl3) 8.10 (1H, br s), 7.36 (1H, dd, J=10.7, 7.8 Hz), 7.22 (1H, t, J=2.8 Hz), 7.17 (1H, dd, J=7.4, 3.1 Hz), 6.50 (1H, m). filtered through Celite The filtrate was concentrated in vacuo the crude product purified by silica gel column chromatography (hexanes/ethyl acetate, 8:2)

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

Procedure: A suspension of 0.12 g of sodium hydride dispersion in 15 ml of tetrahydrofuran was treated with 0.5 g of 5,6-difluoroindole at 0° and stirred at this temperature for 1 hour. After the addition of 0.46 mlof (S)-methyloxirane the reaction mixture was stirred at room temperature for 60 hours and subsequently treated with water. The mixture was diluted with ether, washed twice with water and with saturated sodium chloride solution and the organic phase was dried over sodium sulfate. After removal of the solvent the residue was chromatographed over 35 g of silica gel with toluene-ethyl acetate (19:1). There was obtained 0.5 g (74%) of (S)-1-(5,6-difluoro-indol-1-yl)-propan-2-ol as yellowish crystals with m.p. 116°-118°. was stirred at room temperature for 60 hours washed twice with water and with saturated sodium chloride solution the organic phase was dried over sodium sulfate After removal of the solvent the residue was chromatographed over 35 g of silica gel with toluene-ethyl acetate (19:1)

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

Procedure: A suspension of 0.12 g of sodium hydride dispersion in 15 ml of tetrahydrofuran was treated with 0.5 g of 5,6-difluoroindole at 0° and stirred at this temperature for 1 hour. After the addition of 0.46 mlof (S)-methyloxirane the reaction mixture was stirred at room temperature for 60 hours and subsequently treated with water. The mixture was diluted with ether, washed twice with water and with saturated sodium chloride solution and the organic phase was dried over sodium sulfate. After removal of the solvent the residue was chromatographed over 35 g of silica gel with toluene-ethyl acetate (19:1). There was obtained 0.5 g (74%) of (S)-1-(5,6-difluoro-indol-1-yl)-propan-2-ol as yellowish crystals with m.p. 116°-118°. was stirred at room temperature for 60 hours washed twice with water and with saturated sodium chloride solution the organic phase was dried over sodium sulfate After removal of the solvent the residue was chromatographed over 35 g of silica gel with toluene-ethyl acetate (19:1)

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

Procedure: A suspension of 0.12 g of sodium hydride dispersion in 15 ml of tetrahydrofuran was treated with 0.5 g of 5,6-difluoroindole at 0° and stirred at this temperature for 1 hour. After the addition of 0.46 ml of (R)-methyloxirane the reaction mixture was stirred at room temperature for 60 hours and subsequently treated with water. The mixture was diluted with ether, washed twice with water and with saturated sodium chloride solution and the organic phase was dried over sodium sulfate. After removal of the solvent the residue was chromatographed over 35 g of silica gel with toluene-ethyl acetate (19:1). 0.46 g (66.5%) of (R)-1-(5,6-difluoro-indol-1-yl)-propan-2-ol was obtained as yellowish crystals with m.p. 114°-116°. was stirred at room temperature for 60 hours washed twice with water and with saturated sodium chloride solution the organic phase was dried over sodium sulfate After removal of the solvent the residue was chromatographed over 35 g of silica gel with toluene-ethyl acetate (19:1)

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

Procedure: To a mixture of 5,6-difluoro-1H-indole (500 mg; 3.27 mmol) and KOH (458 mg; 8.18 mmol) in DMF (6.2 mL) was added a solution of iodine (837.5 mg; 3.3 mmol) in DMF (6.3 mL). The mixture was stirred at r.t. for 12 hours. It was poured into an ice-water mixture (60 mL) and extracted with EtOAc (20 mL×3). The combined organic layers was washed with brine (100 mL) and dried over anhydrous Na2SO4, filtered, concentrated to afford 930 mg (100%) of the title compound as a red solid. It was used to next step without further purification. extracted with EtOAc (20 mL×3) The combined organic layers was washed with brine (100 mL) dried over anhydrous Na2SO4 filtered concentrated

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

Procedure: To a mixture of 5,6-difluoro-1H-indole (500 mg; 3.27 mmol) and KOH (458 mg; 8.18 mmol) in DMF (6.2 mL) was added a solution of iodine (837.5 mg; 3.3 mmol) in DMF (6.3 mL). The mixture was stirred at r.t. for 12 hours. It was poured into an ice-water mixture (60 mL) and extracted with EtOAc (20 mL×3). The combined organic layers was washed with brine (100 mL) and dried over anhydrous Na2SO4, filtered, concentrated to afford 930 mg (100%) of the title compound as a red solid. It was used to next step without further purification. extracted with EtOAc (20 mL×3) The combined organic layers was washed with brine (100 mL) dried over anhydrous Na2SO4 filtered concentrated

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

Procedure: A suspension of [2-(4,5-difluoro-2-nitro-phenyl)-vinyl]-dimethyl-amine (7.0 g, 30.7 mmol) and 10% palladium on charcoal (1.4 g) in methyl alcohol was hydrogenated in a Parr apparatus at 50 psi for 2 h and then filtered through Celite. The filtrate was concentrated in vacuo and the crude product purified by silica gel column chromatography (hexanes/ethyl acetate, 8:2) to afford 5,6-difluoroindole (1.28 g, 28%) as a yellow solid. 1H-NMR δ(400 MHz, CDCl3) 8.10 (1H, br s), 7.36 (1H, dd, J=10.7, 7.8 Hz), 7.22 (1H, t, J=2.8 Hz), 7.17 (1H, dd, J=7.4, 3.1 Hz), 6.50 (1H, m). filtered through Celite The filtrate was concentrated in vacuo the crude product purified by silica gel column chromatography (hexanes/ethyl acetate, 8:2)