Acetic Acid → 2-(5-Allyl-6-ethyl-pyridin-3-ylmethyl)-4,5,7-trifluoro-benzothiazole

Participants

Reaction Steps

In a teflon screwcap glass pressure vessel a solution of 5-allyl-6-ethyl-pyridin-3-yl-acetonitrile (0.70 g, 3.76 mmol), 2-amino-3,4,6-trifluoro-benzenethiol hydrochloride (1.2 g, 5.64 mmol), 2,6-di-tert-butyl-4-methylphenol (BHT) (20 mg) and acetic acid (0.25 mL, 4.51 mmol) in 2,2,2-trifluoroethanol (5 mL, 0.8 M, degassed with nitrogen) is warmed to 90° C. and stirred overnight. The mixture is cooled to room temperature, added to saturated aq sodium bicarbonate (15 mL), extracted with ethyl acetate (2×15 mL) and dried over sodium sulfate. Purification by medium-pressure liquid chromatography (MPLC) on silica (20-40% ethyl acetate in heptane) provided 2-(5-allyl-6-ethyl-pyridin-3-ylmethyl)-4,5,7-trifluoro-benzothiazole as a yellow oil (1.14 g, 87%): Rf 0.38 (30% ethyl acetate in n-heptane), 1H NMR (CDCl3, 300 MHz) δ 8.45 (d, J=2.1 Hz, 1 H), 7.44 (d, J=2.1 Hz, 1 H), 7.01 (ddd, J1=10.5 Hz, J2=8.7 Hz, J3=5.6 Hz, 1 H), 5.91 (ddt, J1=17.0 Hz, J2=10.3 Hz, J3=6.3 Hz, 1 H), 5.13 (dd, J1=10.3 Hz, J2=1.5 Hz, 1 H), 5.01 (dd, J1=17.0 Hz, J2=1.5 Hz, 1 H), 3.40 (d, J=6.3 Hz, 2 H), 2.83 (q, J=7.5 Hz, 2 H), 1.29 (t, J=7.5 Hz, 3 H); ESI-LCMS m/z calcd for C18H15F3N2S: 348.1; found 349.0 (M+1)+.

Provenance & Evidence