Triethylamine → Tert-butyl 4-(2,5-dicyano-3,4,6-trifluorophenyl)piperazine-1-carboxylate

Temperature

55 °C

2,3,5,6-tetrafluoroterephthalonitrile (1 g, 5 mmol) was dissolved in acetone (15 mL) in a 2-necked flask under Nitrogen. A solution of tert-butyl piperazine-1-carboxylate (1.39 g, 7.5 mmol) in water (3 mL) was then added followed by triethylamine (1.01 g, 10 mmol). The solution was heated to 55° C. for 8 h then cooled to rt. The resulting solid was filtered then washed with acetone. The filtrate was concentrated under vacuum and the residue was dissolved again in DCM (30 mL) and washed once with 1M HCl (30 mL) and once with brine (30 mL). The organics were dried over Na2SO4, filtered and the solvent removed in vacuo to give tert-butyl 4-(2,5-dicyano-3,4,6-trifluorophenyl)piperazine-1-carboxylate as a bright yellow solid (0.938 g, 51% yield).

1. temperaturethen cooled to rt
2. filtrationThe resulting solid was filtered
3. washthen washed with acetone
4. concentrationThe filtrate was concentrated under vacuum
5. dissolutionthe residue was dissolved again in DCM (30 mL)
6. washwashed once with 1M HCl (30 mL) and once with brine (30 mL)
7. dry with materialThe organics were dried over Na2SO4
8. filtrationfiltered
9. customthe solvent removed in vacuo

ORD record

ord-0a1c2be596b64a1daf884580694e7663

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09242987B2