反应详情

50 g of phosphorus pentoxide are covered, by pouring, with 400 ml of methanesulphonic acid and the whole is stirred at 60° until a clear solution has formed. 30.4 g (0.2 mol) of 1,2-dimethoxy-4-methylbenzene and 43 g (0.2 mol) of 2-methylbenzenesulphonic acid (80% strength) are then added, and the internal temperature is increased to 80° for 30 minutes. The mixture is poured onto 4 liters of ice-water and extracted with ethyl acetate. The extract solution is washed twice with water, dried over sodium sulphate, filtered and concentrated by evaporation in a rotary evaporator. The oil remaining crystallises immediately. It is triturated with diethyl ether and filtered off. In this manner colourless crystals of 1,2-dimethoxy-4-(2-methylphenylsulphonyl)-5-methylbenzene having a melting point of 126°-128° are obtained.

1. customhas formed
2. temperaturethe internal temperature is increased to 80° for 30 minutes
3. extractionextracted with ethyl acetate
4. washThe extract solution is washed twice with water
5. dry with materialdried over sodium sulphate
6. filtrationfiltered
7. concentrationconcentrated by evaporation in a rotary evaporator
8. customThe oil remaining crystallises immediately
9. customIt is triturated with diethyl ether
10. filtrationfiltered off