8-hydroxy-2,2-dimethyl-1,3-benzodioxin-4-one

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

Procedure: Cesium carbonate (5.46 g, 16.6 mmol) was added to a solution of 8-hydroxy-2,2-dimethyl-4H-1,3-benzodioxin-4-one (123a, 1.50 g, 7.73 mmol) in N,N-dimethylformamide (31 mL) and the mixture stirred at room temperature for five minutes before 2-iodopropane (1.00 mL, 10.0 mmol) was added. The mixture was stirred at room temperature for 80 minutes, then partitioned between deionized water (30 mL) and ethyl acetate (2×75 mL). The combined organic extracts were dried over magnesium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (ethyl acetate/heptane) to give 2,2-dimethyl-8-(propan-2-yloxy)-4H-1,3-benzodioxin-4-one (123b, 1.41 g, 77% yield) as a colorless gel which slowly crystallized to a white solid. was added partitioned between deionized water (30 mL) and ethyl acetate (2×75 mL) The combined organic extracts were dried over magnesium sulfate filtered concentrated under vacuum purified by column chromatography (ethyl acetate/heptane)

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

Procedure: Cesium carbonate (5.46 g, 16.6 mmol) was added to a solution of 8-hydroxy-2,2-dimethyl-4H-1,3-benzodioxin-4-one (123a, 1.50 g, 7.73 mmol) in N,N-dimethylformamide (31 mL) and the mixture stirred at room temperature for five minutes before 2-iodopropane (1.00 mL, 10.0 mmol) was added. The mixture was stirred at room temperature for 80 minutes, then partitioned between deionized water (30 mL) and ethyl acetate (2×75 mL). The combined organic extracts were dried over magnesium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (ethyl acetate/heptane) to give 2,2-dimethyl-8-(propan-2-yloxy)-4H-1,3-benzodioxin-4-one (123b, 1.41 g, 77% yield) as a colorless gel which slowly crystallized to a white solid. was added partitioned between deionized water (30 mL) and ethyl acetate (2×75 mL) The combined organic extracts were dried over magnesium sulfate filtered concentrated under vacuum purified by column chromatography (ethyl acetate/heptane)

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

Procedure: Trifluoroacetic acid anhydride (42.0 mL, 300 mmol) was added dropwise to a cooled (−5° C.) solution of 2,3-dihydroxybenzoic acid (8.30 g, 53.9 mmol) in trifluoroacetic acid (83 mL), with stirring. Acetone (14.0 mL, 190 mmol) was then added dropwise over 27 minutes, and the mixture stirred and allowed to warm gradually to room temperature over 16.5 hours. The volatiles were concentrated under vacuum, the residue was dissolved in ethyl acetate (100 mL), and the solution slowly added to a rapidly stirred saturated aqueous sodium bicarbonate solution (200 mL). After gas evolution ceased, the mixture was extracted with ethyl acetate (3×100 mL). The combined organic extracts were dried over magnesium sulfate, filtered, concentrated, and purified by silica gel chromatography (ethyl acetate/heptane) to give 8-hydroxy-2,2-dimethyl-4H-1,3-benzodioxin-4-one (123a, 3.55 g, 34% yield) as an off-white solid. the mixture stirred The volatiles were concentrated under vacuum the residue was dissolved in ethyl acetate (100 mL) the solution slowly added to a rapidly stirred saturated aqueous sodium bicarbonate solution (200 mL) the mixture was extracted with ethyl acetate (3×100 mL) The combined organic extracts were dried over magnesium sulfate filtered concentrated purified by silica gel chromatography (ethyl acetate/heptane)

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

Procedure: The title compound was prepared from 8-hydroxy-2,2-dimethyl-benzo[1,3]dioxin-4-one and benzylbromide under conditions analogous to experimental example 38-b, to give the desired product as an off-white solid. MS: (+) m/z 285.10 (M+1).

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

Procedure: Cesium carbonate (5.46 g, 16.6 mmol) was added to a solution of 8-hydroxy-2,2-dimethyl-4H-1,3-benzodioxin-4-one (123a, 1.50 g, 7.73 mmol) in N,N-dimethylformamide (31 mL) and the mixture stirred at room temperature for five minutes before 2-iodopropane (1.00 mL, 10.0 mmol) was added. The mixture was stirred at room temperature for 80 minutes, then partitioned between deionized water (30 mL) and ethyl acetate (2×75 mL). The combined organic extracts were dried over magnesium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (ethyl acetate/heptane) to give 2,2-dimethyl-8-(propan-2-yloxy)-4H-1,3-benzodioxin-4-one (123b, 1.41 g, 77% yield) as a colorless gel which slowly crystallized to a white solid. was added partitioned between deionized water (30 mL) and ethyl acetate (2×75 mL) The combined organic extracts were dried over magnesium sulfate filtered concentrated under vacuum purified by column chromatography (ethyl acetate/heptane)

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

Procedure: Trifluoroacetic acid anhydride (42.0 mL, 300 mmol) was added dropwise to a cooled (−5° C.) solution of 2,3-dihydroxybenzoic acid (8.30 g, 53.9 mmol) in trifluoroacetic acid (83 mL), with stirring. Acetone (14.0 mL, 190 mmol) was then added dropwise over 27 minutes, and the mixture stirred and allowed to warm gradually to room temperature over 16.5 hours. The volatiles were concentrated under vacuum, the residue was dissolved in ethyl acetate (100 mL), and the solution slowly added to a rapidly stirred saturated aqueous sodium bicarbonate solution (200 mL). After gas evolution ceased, the mixture was extracted with ethyl acetate (3×100 mL). The combined organic extracts were dried over magnesium sulfate, filtered, concentrated, and purified by silica gel chromatography (ethyl acetate/heptane) to give 8-hydroxy-2,2-dimethyl-4H-1,3-benzodioxin-4-one (123a, 3.55 g, 34% yield) as an off-white solid. the mixture stirred The volatiles were concentrated under vacuum the residue was dissolved in ethyl acetate (100 mL) the solution slowly added to a rapidly stirred saturated aqueous sodium bicarbonate solution (200 mL) the mixture was extracted with ethyl acetate (3×100 mL) The combined organic extracts were dried over magnesium sulfate filtered concentrated purified by silica gel chromatography (ethyl acetate/heptane)