反应详情

A suspension of 6.05 g of ethyl[(6,7-dichloro-2-hydroxymethylbenzo[b]thien-5-yl)oxy]acetate in 40 ml of 95% ethanol and 56 ml of 3N hydrochloric acid is stirred under reflux for 1 hr. The cooled mixture is diluted with 200 ml of water and made acidic with concentrated hydrochloric acid until pH=2. The precipitate is extracted into ethyl acetate (3×200 ml) and the combined organic extracts are washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated. Recrystallization of the residue from acetone-hexane gives 0.5 g of [(6,7-dichloro-2-hydroxymethylbenzo[b]thien-5-yl)oxy]acetic acid, mp 187.5°-118.5°.

1. temperatureunder reflux for 1 hr
2. extractionThe precipitate is extracted into ethyl acetate (3×200 ml)
3. washthe combined organic extracts are washed with brine
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated
7. customRecrystallization of the residue from acetone-hexane