反应详情

A solution of 4-methoxyphthalic acid dimethyl ester (3.1 g, Fluka, U.S.A.) in 10 mL methanol and 35 mL of a 1 M solution of aqueous sodium hydroxide was heated to reflux for 3 hours. The solution was allowed to cool to rt, acidified to pH 2 with 1 M hydrochloric acid, and extracted three times with ethyl acetate. The organic extractions were combined, dried over magnesium sulfate, and reduced in vacuo to cleanly yield 2.43 g of the corresponding diacid. The diacid (1.43 g) and 1.9 mL of acetic anhydride were dissolved in tetrahydrofuran and heated to reflux for 16 hours. The solvent was evaporated to give 5-methoxy-isobenzofuran-1,3-dione (1.25 g).

1. temperatureto reflux for 3 hours
2. extractionextracted three times with ethyl acetate
3. extractionThe organic extractions
4. dry with materialdried over magnesium sulfate
5. dissolutionThe diacid (1.43 g) and 1.9 mL of acetic anhydride were dissolved in tetrahydrofuran
6. temperatureheated
7. temperatureto reflux for 16 hours
8. customThe solvent was evaporated