Diisopropylethylamine → 3-Fluoro-4-(4-{2-methoxyethyl}-3-oxopiperazin-1-yl)nitrobenzene

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Reaction Steps

1-(2-Methoxyethyl)-2-oxopiperazine (4TFA salt, 13.5 g) was dissolved in acetonitrile (200 ml), and N,N-diisopropylethylamine (22.6 ml) followed by 3,4-difluoronitrobenzene (2.2 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-{2-methoxyethyl}-3-oxopiperazin-1-yl)nitrobenzene as a solid (4.07 g).

Provenance & Evidence