2-hydroxy-4-methoxybenzaldehyde

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

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

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

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

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

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

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

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

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

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ex-62A: A solution of 2-hydroxy-4-methoxybenzaldehyde (3.03 g, 20 mmol) in 25 mL of dichloromethane was cooled to 0° C. and treated dropwise with a solution of bromine (3.41 g, 21 mmol) in 10 mL of dichloromethane. The reaction mixture was stirred at 0° C. for 1.5 hours. The solvent was removed by rotary evaporation to give a residue. The residue was taken up in EtOAc and washed with 3 portions of water. The organic layer was dried over MgSO4. The drying agent was removed by filtration, and solvent was removed by rotary evaporation to give 3.9 g of the desired 5-bromo-2-hydroxy-4-methoxybenzaldehyde as a solid, m.p. 111-115° C. The solvent was removed by rotary evaporation to give a residue washed with 3 portions of water The organic layer was dried over MgSO4 The drying agent was removed by filtration, and solvent was removed by rotary evaporation

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

Procedure: To a solution of 100 g of 2-hydroxy-4-methoxybenzaldehyde in 2 liters of acetone add 79.5 ml of allyl bromide and then, gradually, 272 g of potassium carbonate. Heat at reflux for 4 hours and then filter; concentrate the filtrate in vacuo, take up the residue in 1 liter of dichloromethane and wash the solution with 1N sodium hydroxide solution and then with saturated sodium chloride solution. Dry over magnesium sulphate and concentrate in vacuo. Heat at reflux for 4 hours filter concentrate the filtrate in vacuo wash the solution with 1N sodium hydroxide solution Dry over magnesium sulphate concentrate in vacuo

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ex-13B: 2-Hydroxy-4-methoxybenzaldehyde (6.0 g, 39 mmol) was dissolved in dichloromethane (50 mL) and cooled to 0° C. using an ice-water bath. Bromine (6.8 g, 43 mmol) in dichloromethane (2 mL) was added dropwise to the cooled solution and stirred for 2 h at 0° C. The mixture was warmed to room temperature and stirred for an additional 1 h and the resulting yellow precipitate was collected. Recrystallization (ethyl acetate/hexanes) yielded 7.1 g (80%) of 5-bromo-2-hydroxy-4-methoxybenzaldehyde as white needles, mp 63–64° C. 1H-NMR (300 MHz, CDCl3) δ 11.43 (s, 1H), 9.69 (s, 1H), 7.68 (s, 1H), 6.48 (s, 1H), 3.95 (s, 3H). Anal. Calcd. for C8H7BrO3: C, 41.59; H, 3.05; Found: C, 41.86; H, 3.05. The mixture was warmed to room temperature stirred for an additional 1 h the resulting yellow precipitate was collected Recrystallization (ethyl acetate/hexanes)