Trifluoroacetic acid → 4-Methylpyridin-3-ol

Participants

Reaction Steps

(S)-1-t-Butoxycarbonyl-2-pyrrolidinemethanol (590 mg, 2.94 mmol), 4-methyl-3-pyridinol (320 mg, 2.94 mmol), DEAD (509 uL, 3.23 mmol) and PPh3 (848 mg, 3.23 mmol) in THF (100 mL) were allowed to react as described in Example 2a. Solvent was removed, and the residue was chromatographed with CHCl3 /MeOH (10:1) to provide 1.8 g of the crude mixture. This material was immediately treated with trifluoroacetic acid (2.0 mL) at room temperature for 3 hours, and excess trifluoroacetic acid was removed under reduced pressure. Water (3 mL) and EtOAc (20 mL) were added, and the mixture was stirred for 5 minutes. The organic layer was decanted, and the residue washed with EtOAc (3×10 mL). The combined organic layers were dried (Na2SO4) and evaporated. The crude product was purified by flash chromatography on silica gel eluting with CHCl3 /MeOH/NH4OH (10:1:0.02 and 10:1.5:0.1) to provide 52 mg (14% yield from 4-methyl-3-pyridinol) of the title compound. TLC Rf 0.18 (10:1:0.02 CHCl3 /MeOH/NH40H). MS (DCI/NH3) m/e 193 (M+H)+. 1H NMR (CDCl3, 300 MHz) δ: 8.16 (s, 1H, ArH), 8.12 (d, J=6.9 Hz, 1H, ArH), 7.07 (d, J=6.9 Hz, 1H, ArH), 4.12-4.00 (m, 2H, OCH2), 3.75-3.63 (m, 1H, NCH), 3.18-3.02 (m, 2H, NCH2), 2.24 (s, 3H, NCH3), 2.08-1.64 (m, 4H, 2CH2).

Provenance & Evidence