反应详情

5.71 g of 4-(o-methylthiobenzoyl)-5-hydroxybenzocyclobutene-1-carboxylic acid methyl ester are dissolved in 70 ml of ether; 45 ml of 2N sodium hydroxide solution are added and stirring is carried out for 1 hour at room temperature. The aqueous phase is separated off and the ether phase is extracted by shaking twice with 25 ml of water each time. The aqueous phases are combined, acidified with 2N hydrochloric acid and extracted three times with 50 ml of dichloromethane each time. The extracts are combined, washed with water, dried over magnesium sulphate and concentrated by evaporation. After recrystallisation of the residue from dichloromethane/hexane, 4-(o-methylthiobenzoyl)-5-hydroxybenzocyclobutene-1-carboxylic acid is obtained having a melting point of 177°-178°.

1. customThe aqueous phase is separated off
2. extractionthe ether phase is extracted
3. stirringby shaking twice with 25 ml of water each time
4. extractionextracted three times with 50 ml of dichloromethane each time
5. washwashed with water
6. dry with materialdried over magnesium sulphate
7. concentrationconcentrated by evaporation
8. customAfter recrystallisation of the residue from dichloromethane/hexane