反应详情

160 g (732.9 mmol) of (2S)-cyclopentyl-(4-methylphenyl)acetic acid were initially charged in 480 ml of dichloromethane, and 2.1 ml of sulfuric acid and 172 ml (1722.4 mmol) of condensed 2-methylprop-1-ene were added at 10° C. The mixture was stirred at RT overnight. If required, the addition of sulfuric acid and 2-methylprop-1-ene was repeated until all the starting material had been consumed. After the reaction had ended, 21 g of potassium carbonate were added and the mixture was stirred for another 2-3 h (evolution of gas). The mixture was then diluted with 700 ml of water and extracted with ethyl acetate. The organic phase was dried over sodium sulfate, filtered and concentrated on a rotary evaporator. The crude product was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 4:1). This gave 172 g (85% of theory) of the title compound.

1. additionwere added at 10° C
2. customhad been consumed
3. addition21 g of potassium carbonate were added
4. stirringthe mixture was stirred for another 2-3 h (evolution of gas)
5. additionThe mixture was then diluted with 700 ml of water
6. extractionextracted with ethyl acetate
7. dry with materialThe organic phase was dried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated on a rotary evaporator
10. customThe crude product was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 4:1)