反应详情

2.07 g (0.01 mol) of benzofuran-2,3-dione 2-{O-[2-(tetrahydropyran-2-yloxy)-ethyl]-oxime} (XIV-2) are dissolved in 12 ml of methanol and stirred at room temperature with 100 mg of acidic ion exchanger resin for 16 hours. 40 ml of methanol are added to the reaction mixture which is then warmed until the crystals have dissolved. The acidic ion exchanger resin is filtered off, the filtrate is concentrated and the residue is recrystallized from 10 ml of toluene. 1.69 g (81.5% of theory) of crystalline benzofuran-2,3-dione 2-[O-(2-hydroxy-ethyl)-oxime] (VII-1) of melting point 110-111° C. are obtained.

1. temperatureis then warmed until the crystals
2. dissolutionhave dissolved
3. filtrationThe acidic ion exchanger resin is filtered off
4. concentrationthe filtrate is concentrated
5. customthe residue is recrystallized from 10 ml of toluene