3-bromo-1,1-dimethoxypropan-2-one

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

Procedure: To a solution of benzamidine 207 (1.44 g, 12 mmol) and potassium carbonate (4.1 g, 30 mmol) in anhydrous DMF (25 mL) is slowly added a solution of 3-bromo-1,1-dimethoxy-propan-2-one 206 (1.97 g, 10 mmol) in anhydrous DMF (10 mL) over 30 min. The mixture is then heated at 50–60° C. for 2 h. After cooling to room temperature, ethyl acetate (100 mL) and water (100 mL) were added. The organic phase is separated and the aqueous phase is extracted with ethyl acetate twice and the combined organic phase is washed with water (3×20 mL) and brine. Removal of solvents under reduced pressure and purification of the residue by column chromatography affords the desired product as a white solid. Yield: 2.08 g; LC-MS (MH+): 219. 1H NMR (300 MHz, CDCl3) δ 7.88–7.85 (m, 2H), 7.37–7.46 (m, 4H), 5.49 (s, 1H), 3.36 (s, 6H). The mixture is then heated at 50–60° C. for 2 h The organic phase is separated the aqueous phase is extracted with ethyl acetate twice the combined organic phase is washed with water (3×20 mL) and brine Removal of solvents under reduced pressure and purification of the residue by column chromatography

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

Procedure: Bromine (80 g, 0.5 mol) is added dropwise to a solution of 1,1-dimethoxy-propan-2-one 205 (59 g, 0.5 mol) in anhydrous methanol (400 mL) at 0° C. and the solution is continued stirring at room temperature for 48 h. The solvent is removed under reduced pressure and the residue is dried in vacuo and used without further purification. The solvent is removed under reduced pressure the residue is dried in vacuo used without further purification

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

Procedure: Bromine (80 g, 0.5 mol) is added dropwise to a solution of 1,1-dimethoxy-propan-2-one 205 (59 g, 0.5 mol) in anhydrous methanol (400 mL) at 0° C. and the solution is continued stirring at room temperature for 48 h. The solvent is removed under reduced pressure and the residue is dried in vacuo and used without further purification. The solvent is removed under reduced pressure the residue is dried in vacuo used without further purification

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

Procedure: A solution of 1,1-bis(methyloxy)-2-propanone (40.1 mL, 339 mmol) in 5% (v/v) methanol/acetonitrile (200 mL) was cooled to <5° C. while stirring. A 1 mL portion of a solution of bromine (17.44 mL, 339 mmol) in acetonitrile (30 mL) was added and the mixture was stirred until the solution was decolorized. The remainder of the bromine solution was added to the reaction mixture over 6-8 hrs while maintaining an internal temperature of <10° C. The mixture was stirred at RT overnight. Sodium bicarbonate (30.2 g, 360 mmol) was added and the mixture was stirred for 1 hr, then filtered. The filtrate was concentrated and t-butyl methyl ether (30 mL) and heptane (15 mL) were added. The mixture was washed with aqueous sodium bicarbonate (6.0 g in 60 mL water) and the organic layer was dried over sodium sulfate. The solvent was evaporated to give the title compound (47.03 g, 70%) as a yellow oil. 1H NMR (400 MHz, chloroform-d) δ ppm 4.64 (s, 1H), 4.13 (s, 2H), 3.35 (s, 6H). the mixture was stirred until the solution while maintaining an internal temperature of <10° C The mixture was stirred at RT overnight the mixture was stirred for 1 hr filtered The filtrate was concentrated t-butyl methyl ether (30 mL) and heptane (15 mL) were added The mixture was washed with aqueous sodium bicarbonate (6.0 g in 60 mL water) the organic layer was dried over sodium sulfate The solvent was evaporated

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of benzamidine 207 (1.44 g, 12 mmol) and potassium carbonate (4.1 g, 30 mmol) in anhydrous DMF (25 mL) is slowly added a solution of 3-bromo-1,1-dimethoxy-propan-2-one 206 (1.97 g, 10 mmol) in anhydrous DMF (10 mL) over 30 min. The mixture is then heated at 50-60° C. for 2 h. After cooling to room temperature, ethyl acetate (100 mL) and water (100 mL) were added. The organic phase is separated and the aqueous phase is extracted with ethyl acetate twice and the combined organic phase is washed with water (3×20 mL) and brine. Removal of solvents under reduced pressure and purification of the residue by column chromatography affords the desired product as a white solid. Yield: 2.08 g; LC-MS (MH+): 219. 1H NMR (300 MHz, CDCl3) δ 7.88-7.85 (m, 2H), 7.37-7.46 (m, 4H), 5.49 (s, 1H), 3.36 (s, 6H). After cooling to room temperature The organic phase is separated the aqueous phase is extracted with ethyl acetate twice the combined organic phase is washed with water (3×20 mL) and brine Removal of solvents under reduced pressure and purification of the residue by column chromatography

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

Procedure: Bromine (80 g, 0.5 mol) is added dropwise to a solution of 1,1-dimethoxy-propan-2-one 205 (59 g, 0.5 mol) in anhydrous methanol (400 mL) at 0° C. and the solution is continued stirring at room temperature for 48h. The solvent is removed under reduced pressure and the residue is dried in vacuo and used without further purification. The solvent is removed under reduced pressure the residue is dried in vacuo used without further purification

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

Procedure: To a solution of benzamidine 207 (1.44 g, 12 mmol) and potassium carbonate (4.1 g, 30 mmol) in anhydrous DMF (25 mL) is slowly added a solution of 3-bromo-1,1-dimethoxy-propan-2-one 206 (1.97 g, 10 mmol) in anhydrous DMF (10 mL) over 30 min. The mixture is then heated at 50–60° C. for 2 h. After cooling to room temperature, ethyl acetate (100 mL) and water (100 mL) were added. The organic phase is separated and the aqueous phase is extracted with ethyl acetate twice and the combined organic phase is washed with water (3×20 mL) and brine. Removal of solvents under reduced pressure and purification of the residue by column chromatography affords the desired product as a white solid. Yield: 2.08 g; LC-MS (MH+): 219. 1H NMR (300 MHz, CDCl3) δ 7.88–7.85 (m, 2H), 7.37–7.46 (m, 4H), 5.49 (s, 1H), 3.36 (s, 6H). The mixture is then heated at 50–60° C. for 2 h The organic phase is separated the aqueous phase is extracted with ethyl acetate twice the combined organic phase is washed with water (3×20 mL) and brine Removal of solvents under reduced pressure and purification of the residue by column chromatography

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

Procedure: Bromine (80 g, 0.5 mol) is added dropwise to a solution of 1,1-dimethoxy-propan-2-one 205 (59 g, 0.5 mol) in anhydrous methanol (400 mL) at 0° C. and the solution is continued stirring at room temperature for 48 h. The solvent is removed under reduced pressure and the residue is dried in vacuo and used without further purification. The solvent is removed under reduced pressure the residue is dried in vacuo used without further purification