反应详情

1-Ethyl-2-oxopiperazine (3TFA salt, 10.5 g) was dissolved in acetonitrile (200 ml), and N,N-diisopropylethylamine (19.5 ml) followed by 3,4-difluoronitrobenzene (2.25 ml) were added. The mixture was heated to reflux for 18 hours. Solvent was evaporated, and the residue chromatographed on silica using as eluant a gradient increasing in polarity from 0 to 4% methanol in dichloromethane. Relevant fractions were combined and evaporated to give a solid containing some N,N-diisopropylethylamine trifluoroacetate. The solid was purified by dissolving in ethyl acetate and washing well with water. Evaporation of the organic layer gave 3-fluoro-4-(4-ethyl-3-oxopiperazin-1-yl)nitrobenzene as a solid (3.44 g).

1. additionwere added
2. temperatureThe mixture was heated
3. temperatureto reflux for 18 hours
4. customSolvent was evaporated
5. customthe residue chromatographed on silica using as eluant
6. temperaturea gradient increasing in polarity from 0 to 4% methanol in dichloromethane
7. customevaporated
8. customto give a solid
9. customThe solid was purified
10. dissolutionby dissolving in ethyl acetate
11. washwashing well with water
12. customEvaporation of the organic layer