5,6-Dimethyl-2-benzofuran-1,3-dione → HCID 23084580, compound

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Reaction Steps

To a solution of 4,5-dimethylphthalic anhydride (1.5 g, 8.5 mmol) in anhydrous tetrahydrofuran (25 ml) was added a 1.0 mol/L solution of tri-tert-butoxy aluminohydride in anhydrous tetrahydrofuran (8.5 ml) under ice cooling and argon atmosphere, and stirred for 1 hr under ice cooling. To the reaction solution was added ice-cold water, and the insoluble materials was filtered off. The filtrate was concentrated under reduced pressure to give crude 5,6-dimethyl-3-hydroxyphthalide. To this was added methyl iodide (12 g, 85 mmol) and K2CO3 (9.4 g, 68 mmol), and heated under reflux in acetone solvent for 5 hrs. The reaction solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (chloroform) to give 0.64 g of methyl 4,5-dimethyl-2-formylbenzoate.

Provenance & Evidence