反应详情

A mixture of 4-cyclohexylcyclohexanone (1.54 g), 1-(4-ethoxycarbonylphenyl)piperazine (2 g) and titanium(IV) isopropoxide (3.18 ml) was stirred at room temperature. After 1 hour, the IR spectrum of the mixture showed no ketone band, and the viscous solution was diluted with absolute ethanol (8.5 ml). Sodium cyanoborohydride (0.343 g) was added, and the solution was stirred for 3 hours. Water (3 ml) was added with stirring, and the resulting in organic precipitate was filtered and washed with ethanol. The filtrate was extracted with ethyl acetate. The organic layer was taken and dried over magnesium sulfate. The magnesium sulfate was filtered off, and filtrate was evaporated under reduced pressure. The residue was subjected to column chromatography on silica gel and eluted with (hexane/ethyl acetate)=(3/1). The fractions containing the less polar compound were collected and evaporated under reduced pressure to give ethyl 4-[4-(cis-4-cyclohexylcyclohexyl)piperazin-1-yl]benzoate (692 mg) as byproduct. The fractions containing the more polar compound were collected and evaporated under reduced pressure to give ethyl 4-[4-(trans-4-cyclohexylcyclohexyl)piperazin-1-yl]benzoate (587 mg).

1. stirringthe solution was stirred for 3 hours
2. stirringwith stirring
3. filtrationthe resulting in organic precipitate was filtered
4. washwashed with ethanol
5. extractionThe filtrate was extracted with ethyl acetate
6. dry with materialdried over magnesium sulfate
7. filtrationThe magnesium sulfate was filtered off
8. customfiltrate was evaporated under reduced pressure
9. washeluted with (hexane/ethyl acetate)=(3/1)
10. additionThe fractions containing the less polar compound
11. customwere collected
12. customevaporated under reduced pressure