反应详情

28.26 g of aluminium trichloride are suspended in 70 ml of dichloromethane and, over a period of 15 minutes, 10.19 g of 5-methoxybenzocyclobutene-1-carboxylic acid methyl ester are added dropwise at from 20° to 30°. Stirring is carried out for 30 minutes, 20.8 g of m-methylthiobenzoyl chloride are added dropwise over a period of 20 minutes and the whole is stirred for 4 hours at room temperature, poured into a mixture of 200 g of ice, 20 ml of concentrated hydrochloric acid and 200 ml of water, stirred for 30 minutes and extracted by shaking twice with 50 ml of dichloromethane each time and once with 50 ml of a mixture of trichloromethane and methanol (3:1). The organic phases are combined, washed twice with water, dried over magnesium sulphate, treated with kieselguhr and concentrated by evaporation. Chromatography over silica gel using hexane/ethyl acetate (4:1) as eluant yields 4-(m-methylthiobenzoyl)-5-hydroxybenzocyclobutene-1-carboxylic acid methyl ester in the form of a yellow oil.

1. stirringthe whole is stirred for 4 hours at room temperature
2. stirringstirred for 30 minutes
3. extractionextracted
4. stirringby shaking twice with 50 ml of dichloromethane each time
5. washwashed twice with water
6. dry with materialdried over magnesium sulphate
7. additiontreated with kieselguhr
8. concentrationconcentrated by evaporation