反应详情

A mixture of 174.3 g of 4-(1,4-dioxaspiro[4,5]dec-8-yl)-1-(3-fluorophenyl)cyclohexanol, 1000 ml of 1,2-dichloroethane, 25 ml of ethylene glycol and 25 g of Amberlyst 15 was boiled under reflux for 22 hrs., the condensate being dried over a dropping funnel filled with 175 g of neutral aluminiumoxide. Then, the reaction mixture was cooled, filtered, washed with water and the organic phase was dried over sodium sulphate. Subsequent chromatography on 1000 g of silica gel with hexane/ethyl acetate (90:1) gave 124.2 g of 4-(1,4-dioxaspiro[4,5]dec-8-yl)-1-(3-fluorophenyl)-cyclohexene as colorless crystals. M.p. of a sample recrystallized from methylene chloride/hexane: 133.7°-135.3° C.

1. temperatureunder reflux for 22 hrs
2. custom, the condensate being dried over a dropping funnel
3. additionfilled with 175 g of neutral aluminiumoxide
4. temperatureThen, the reaction mixture was cooled
5. filtrationfiltered
6. washwashed with water
7. dry with materialthe organic phase was dried over sodium sulphate