Trifluoroacetic acid → 2-Fluoro-5-(4-(methylthio)benzyl)pyridine

Participants

Reaction Steps

A solution of (6-fluoropyridin-3-yl)(4-(methylthio)phenyl)methanol (1.716 g, 6.88 mmol) in DCM (3.0 mL) was treated with trifluoroacetic acid (2.56 mL, 34.4 mmol) resulting in a green solution. The mixture was stirred for 5 min, and then triethylsilane (3.30 mL, 20.65 mmol) was added dropwise. The green color dissipated rapidly to give a straw colored solution, and a brief exotherm was observed (DCM started refluxing). The mixture was stirred for 30 min, and then extracted into DCM from saturated aqueous NaHCO3. The DCM extracts were dried (MgSO4) and purified by flash chromatography (5% to 7.5% EtOAc/hexane) to give 2-fluoro-5-(4-(methylthio)benzyl)pyridine (89% over 2 steps) as a colorless oil. 1H NMR (400 MHz, d6-DMSO) δ 8.15 (s, 1H); 7.81 (t, J=8.22 Hz, 1H); 7.20 (s, 4H); 7.10 (d, J=8.41 Hz, 1H); 3.94 (s, 2H); 2.44 (s, 3H). 19F NMR (376 MHz, d6-DMSO) δ −72.37 (s, 1F). m/z (ESI, +ve ion) 234.0 (M+H)+.

Provenance & Evidence