Piperazine → 1-(2-fluoro-4-nitrophenyl)piperazine

Participants

Reaction Steps

A solution of 12.0 g (75.42 mmol) of 3,4-difluoronitrobenzene (2) in 150 mL of acetonitrile was treated with 16.24 g (188.6 mmol) of piperazine, followed by warming at reflux for 3 hours. The solution was cooled to ambient temperature and was concentrated in vacuo. The residue was diluted with 200 mL of water and was extracted with ethyl acetate (3×250 mL). The combined organic layers were extracted with water (200 mL) and saturated NaCl solution (200 mL), followed by drying (Na2SO4). The solution was concentrated in vacuo to afford an orange oil which was chromatographed over 450 g of 230-400 mesh silica gel eluting initially with dichloromethane until the least polar fractions had eluted and then elution was continued with 2% (v/v) methanol-chloroform and then with 10% (v/v) methanol-chloroform. These procedures afforded 13.83 g (81%) of the desired piperazine derivative 3, mp=68.5°-71° C.

Provenance & Evidence