2-Fluoro-4-iodoaniline → 4-Butyl-2-fluoroaniline

Participants

Reaction Conditions

Reaction Steps

ZnCl2 (5. 17 g, 38.0 mmol) was weighed into a flask, which was then flame dried and flushed with N2. Anhydrous THF (20 ml) was then added at 0° C., followed by 2.5 M nBuLi (15.2 ml, 38.0 mmol). The reaction mixture was stirred at 0° C. for 15 min, after which 2-fluoro-4-iodoaniline (3.00 g, 12.7 mmol) in anhydrous THF (10 ml) and Pd(PPh3)4 (0.74 g, 0.64 mmol) were added sequentially. The mixture was allowed to warm to RT and stirred for a further 6 h. The mixture was poured into ice/Et2O, the organic layer separated and the aqueous layer further extracted with Et2O. The combined organic fractions were washed with sat. NaHCO3, dried (Na2SO4) and concentrated under reduced pressure. The resulting solid was removed from the mixture by filtration and the filtrate purified by flash chromatography on silica (12.5% EtOAc/Hexane as eluant) to give the desired product (30%, 3.7 mmol). 1H NMR [400 MHz, CDCl3]δ 6.80 (dd, J=12.1, 1.8 Hz, 1 H), 6.76-6.65 (m, 2 H), 3.65 (br s, 2 H), 2.49 (t, J=7.7 Hz, 2 H), 1.57-1.49 (m, 2 H), 1.32 (sextet, J=7.3 Hz, 2 H), 0.91 (t, J=7.3 Hz, 3 H). LCMS (ACPI+) 168 (100%). Step B: Preparation of 2-(4-butyl-2-fluoroanilino)-3,4-difluorobenzoic acid

Provenance & Evidence