1,2,4-Trifluoro-5-nitrobenzene → 5-cyclopropyl-N-(4,5-difluoro-2-nitrophenyl)-1H-pyrazol-3-amine

Participants

Reaction Conditions

Reaction Steps

To a solution of 1,2,4-trifluoro-5-nitrobenzene (3.0 g, 18 mmol) and DIEA (4.2 ml, 24 mmol) in dry THF (20 ml) was added dropwise a solution of 5-cyclopropyl-1H-pyrazol-3-amine (2.0 g, 16 mmol) in THF (5 ml) at 0° C. After addition, the reaction mixture was stirred at 25° C. for 20 hrs. It was then heated to 40° C. for 40 hrs. The solvent was removed under reduced pressure and the resulted residue was purified by column chromatography (hexane:EtOAc=5:2). Recrystallization from EtOAc (10 ml) and hexanes (˜100 ml) gave the title compound as red crystals (0.8 g, 18%). NMR (400 MHz) 12.36 (s, 1H), 9.79 (s, 1H), 8.27 (m, 2H), 5.93 (s, 1H), 1.90 (m, 1H), 0.93 (m, 2H), 0.72 (m, 2H). MS: Calcd.: 280; Found: [M+H]+ 281.

Provenance & Evidence