Diisopropylethylamine → 3-Fluoro-4-(4-ethyl-3-oxopiperazin-1-yl)nitrobenzene

Participants

Reaction Steps

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).

Provenance & Evidence