trifluoroMethyl-[1,2,4]oxadiazol-3-yl)-aniline synthesis

Yield:71754-23-9 57%

Reaction Conditions:

with sodium dithionite;tetrabutylammomium bromide in tetrahydrofuran;water at 20; for 2 h;

Steps:

50 3-(5-(Trifluoromethyl)-1,2,4-oxadiazol-3-yl)aniline

Sodium dithionite (1.61 g, 9.2 mmol) and a catalytic amount of tetra-n-butylammonium bromide (20 mg) were added to a solution of 3-(3-nitrophenyl)-5-(trifluoromethyl)-1,2,4-oxadiazole (1.6 g, 6.1 mmol) in THF-H₂O (30 mL, 1:1 v/v), and the reaction mixture was stirred at room temperature for 2 h and monitored by TLC (petroleum ether/EtOAc 1:1).
Solvent was removed under reduced pressure and the product was extracted with EtOAc.
The organic layer was washed with brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure.
The crude product was purified by column chromatography (silica gel 60-120 mesh, eluent 30-35% EtOAc in petroleum ether) to afford 3-(5-(trifluoromethyl)-1,2,4-oxadiazol-3-yl)aniline (0.8 g, yield 57%).
¹H NMR (300 MHz, CDCl₃) δ 7.52 - 7.49 (dt, J = 7.7 Hz, 1.2 Hz, 1 H), 7.42 (m, 1 H), 7.30 (t, J = 8.0 Hz, 1 H), 6.89 - 6.86 (ddd, J = 7.9 Hz, 2.4 Hz, 0.9 Hz, 1 H), 3.87 (br s, 2H). MS (ESI) m/z: Calculated for C₉H₆F₃N₃O: 229.05; found: 230.0 (M+H)⁺.

References:

EP2533783,2015,B1 Location in patent:Paragraph 0483-0484