6-bromo-3,4-dihydro-1H-quinoxalin-2-one

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: To a solution of 6-bromo-3,4-dihydro-1H-quinoxalin-2-one (228 mg, 1.00 mmol) in DMF (10 mL) was added NaH (40 mg of a 60% dispersion in mineral oil, 1.00 mmol) and the resulting mixture sonicated for 5 minutes. After stirring at room temperature for 20 minutes, 2-chloro-3,6-difluorobenzylbromide (242 mg, 1.00 mmol) was added and the mixture was stirred for 20 minutes. Solvent was reduced 90% and the residue was triturated with ether (3×1 mL) and water (2×2 mL) to give the title compound (275 mg, 71%). m.p. 214-216° C. (dec); LCMS: m/z=388/390/392 (M+H+); 1H-NMR (DMSO-d6, 400 MHz) δ 7.73 (s, 1H), 7.47-7.42 (m, 1H), 7.35 (s, 1H), 7.32-7.26 (m, 1H), 7.11 (s, 1H), 5.24, (s, 2H), 4.01 (s, 2H). sonicated for 5 minutes the mixture was stirred for 20 minutes the residue was triturated with ether (3×1 mL) and water (2×2 mL)

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-bromo-2,3-diaminopyridine (2.0 g, 10.6 mmol) and glyoxylic acid monohydrate (1.23 g, 13.4 mmol) were combined in water (55 mL), sonicated for 10 minutes and stirred overnight. The product was filtered, washed with water (5×100 mL) and dried under vacuum to afford 2.214 g of crude product. To a suspension of this material in methanol (100 mL) was added NaBH4 (1.0 g, 26.3 mmol) with periodic cooling in an ice water bath to maintain reaction temperature below 35° C. After stirring for 4 hours, the reaction was quenched with 6N HCl (20 mL) and the resulting mixture stirred overnight. The mixture was warmed to 50° C. for 0.5 hour before removing volatile solvents by rotary evaporation. After adjusting the pH of the aqueous reside to 8 by the addition of 10N NaOH, the product was removed by filtration and washed with water (5×50 mL) to give the title compound (1.985 g, 82%). m.p. 265° C. (dec), 1H-NMR (DMSO-d6, 400 MHz) δ 10.47 (s, 1H), 7.65 (d, J=2.1 Hz, 1H), 7.01-6.99 (m, 2H), 3.94 (s, 2H). sonicated for 10 minutes The product was filtered washed with water (5×100 mL) dried under vacuum to afford 2.214 g of crude product with periodic cooling in an ice water bath to maintain reaction temperature below 35° C After stirring for 4 hours the reaction was quenched with 6N HCl (20 mL) the resulting mixture stirred overnight before removing volatile solvents by rotary evaporation by the addition of 10N NaOH the product was removed by filtration washed with water (5×50 mL)

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-bromo-2,3-diaminopyridine (2.0 g, 10.6 mmol) and glyoxylic acid monohydrate (1.23 g, 13.4 mmol) were combined in water (55 mL), sonicated for 10 minutes and stirred overnight. The product was filtered, washed with water (5×100 mL) and dried under vacuum to afford 2.214 g of crude product. To a suspension of this material in methanol (100 mL) was added NaBH4 (1.0 g, 26.3 mmol) with periodic cooling in an ice water bath to maintain reaction temperature below 35° C. After stirring for 4 hours, the reaction was quenched with 6N HCl (20 mL) and the resulting mixture stirred overnight. The mixture was warmed to 50° C. for 0.5 hour before removing volatile solvents by rotary evaporation. After adjusting the pH of the aqueous reside to 8 by the addition of 10N NaOH, the product was removed by filtration and washed with water (5×50 mL) to give the title compound (1.985 g, 82%). m.p. 265° C. (dec), 1H-NMR (DMSO-d6, 400 MHz) δ 10.47 (s, 1H), 7.65 (d, J=2.1 Hz, 1H), 7.01-6.99 (m, 2H), 3.94 (s, 2H). sonicated for 10 minutes The product was filtered washed with water (5×100 mL) dried under vacuum to afford 2.214 g of crude product with periodic cooling in an ice water bath to maintain reaction temperature below 35° C After stirring for 4 hours the reaction was quenched with 6N HCl (20 mL) the resulting mixture stirred overnight before removing volatile solvents by rotary evaporation by the addition of 10N NaOH the product was removed by filtration washed with water (5×50 mL)

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

Procedure: To a solution of 6-bromo-3,4-dihydroquinoxalin-2(1H)-one (370 mg, 1.63 mmol) in 10 ml methanol was added a solution of 37% formaldehyde in water (59 mg, 1.95 mmol) and acetic acid (196 mg, 3.26 mmol). The mixture was stirred at room temperature for 2 h, then refluxed for 1 h. After addition of NaBH3CN (307 mg, 4.89 mmol) stirring was continued for 2.5 h at room temperature. Then methanol was removed under vacuum. To the remaining mixture water was added. Then the solution was basified to pH 8-9 with an aqueous solution of sodium hydrogen carbonate and extracted several times with ethyl acetate. The combined organic layers were washed with brine, dried over MgSO4 and evaporated, affording 6-bromo-4-methyl-3,4-dihydroquinoxalin-2(1H)-one (369 mg, 1.53 mmol, 94%) as off-white solid. refluxed for 1 h stirring was continued for 2.5 h at room temperature Then methanol was removed under vacuum To the remaining mixture water was added extracted several times with ethyl acetate The combined organic layers were washed with brine dried over MgSO4 evaporated

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

Procedure: A mixture of N-(2-amino-4-bromophenyl)-2-chloroacetamide (4.5 g, 17.0 mmol), sodium iodide (101 mg, 2.0 mmol) and sodium carbonate (3.6 g, 33.8 mmol) in 300 ml acetonitrile was refluxed overnight under an atmosphere of nitrogen. Then the acetonitrile was removed under vacuum. The resulting solid was suspended in 150 ml water acidified to pH 5-6 with 1 N HCl. Extraction with ethyl acetate, washing of the combined organic layers with brine, drying over MgSO4, removing the solvent under reduced pressure and purification of the crude product by flash chromatography on silica gel (petroleum ether/ethyl acetate, 1.5/1) yielded 6-bromo-3,4-dihydroquinoxalin-2(1H)-one (1.3 g, 5.8 mmol, 34%) as yellow solid. was refluxed overnight under an atmosphere of nitrogen Then the acetonitrile was removed under vacuum Extraction with ethyl acetate washing of the combined organic layers with brine drying over MgSO4 removing the solvent under reduced pressure and purification of the crude product by flash chromatography on silica gel (petroleum ether/ethyl acetate, 1.5/1)

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: To a solution of 6-bromo-3,4-dihydroquinoxalin-2(1H)-one (370 mg, 1.63 mmol) in 10 ml methanol was added a solution of 37% formaldehyde in water (59 mg, 1.95 mmol) and acetic acid (196 mg, 3.26 mmol). The mixture was stirred at room temperature for 2 h, then refluxed for 1 h. After addition of NaBH3CN (307 mg, 4.89 mmol) stirring was continued for 2.5 h at room temperature. Then methanol was removed under vacuum. To the remaining mixture water was added. Then the solution was basified to pH 8-9 with an aqueous solution of sodium hydrogen carbonate and extracted several times with ethyl acetate. The combined organic layers were washed with brine, dried over MgSO4 and evaporated, affording 6-bromo-4-methyl-3,4-dihydroquinoxalin-2(1H)-one (369 mg, 1.53 mmol, 94%) as off-white solid. refluxed for 1 h stirring was continued for 2.5 h at room temperature Then methanol was removed under vacuum To the remaining mixture water was added extracted several times with ethyl acetate The combined organic layers were washed with brine dried over MgSO4 evaporated

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

Procedure: A mixture of N-(2-amino-4-bromophenyl)-2-chloroacetamide (4.5 g, 17.0 mmol), sodium iodide (101 mg, 2.0 mmol) and sodium carbonate (3.6 g, 33.8 mmol) in 300 ml acetonitrile was refluxed overnight under an atmosphere of nitrogen. Then the acetonitrile was removed under vacuum. The resulting solid was suspended in 150 ml water acidified to pH 5-6 with 1 N HCl. Extraction with ethyl acetate, washing of the combined organic layers with brine, drying over MgSO4, removing the solvent under reduced pressure and purification of the crude product by flash chromatography on silica gel (petroleum ether/ethyl acetate, 1.5/1) yielded 6-bromo-3,4-dihydroquinoxalin-2(1H)-one (1.3 g, 5.8 mmol, 34%) as yellow solid. was refluxed overnight under an atmosphere of nitrogen Then the acetonitrile was removed under vacuum Extraction with ethyl acetate washing of the combined organic layers with brine drying over MgSO4 removing the solvent under reduced pressure and purification of the crude product by flash chromatography on silica gel (petroleum ether/ethyl acetate, 1.5/1)

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

Procedure: To a solution of 6-bromo-3,4-dihydroquinoxalin-2(1H)-one (370 mg, 1.63 mmol) in 10 ml methanol was added a solution of 37% formaldehyde in water (59 mg, 1.95 mmol) and acetic acid (196 mg, 3.26 mmol). The mixture was stirred at room temperature for 2 h, then refluxed for 1 h. After addition of NaBH3CN (307 mg, 4.89 mmol) stirring was continued for 2.5 h at room temperature. Then methanol was removed under vacuum. To the remaining mixture water was added. Then the solution was basified to pH 8-9 with an aqueous solution of sodium hydrogen carbonate and extracted several times with ethyl acetate. The combined organic layers were washed with brine, dried over MgSO4 and evaporated, affording 6-bromo-4-methyl-3,4-dihydroquinoxalin-2(1H)-one (369 mg, 1.53 mmol, 94%) as off-white solid. refluxed for 1 h stirring was continued for 2.5 h at room temperature Then methanol was removed under vacuum To the remaining mixture water was added extracted several times with ethyl acetate The combined organic layers were washed with brine dried over MgSO4 evaporated