Reacción #6857

Ecuación de reacción

hydrochloric acid

4-methoxyphthalic acid dimethyl ester

sodium hydroxide

→

5-methoxy-isobenzofuran-1,3-dione

Rendimiento 50.8%

Disolventes

methanol

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturato reflux for 3 hours
2. 2
   Extracciónextracted three times with ethyl acetate
3. 3
   ExtracciónThe organic extractions
4. 4
   Secadodried over magnesium sulfate
5. 5
   workup.DISSOLUTIONThe diacid (1.43 g) and 1.9 mL of acetic anhydride were dissolved in tetrahydrofuran
6. 6
   Temperaturaheated
7. 7
   Temperaturato reflux for 16 hours
8. 8
   OtroThe solvent was evaporated

Procedimiento

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).

Fuente