HCID 66868438, compound → HCID 70805268, compound

Participants

Reaction Conditions

Reaction Steps

5-(Benzyloxy)-4-oxo-4H-pyran-2-carboxylic acid (10.5 g, 42.7 mmol) was dissolved in sodium hydroxide solution (1.71 g, 42.7 mmol in 77 mL de-ionized water). 2,2,2-Trifluoroethylamine hydrochloride (23.1 g, 171 mmol) was added and the resulting suspension was stirred at 70° C. (oil-bath temperature) in the sealed flask for 17 hours. The reaction mixture was then filtered and the off-white solid was washed with de-ionized water (20 mL×5) to give 5-(benzyloxy)-4-oxo-1-(2,2,2-trifluoroethyl)-1,4-dihydropyridine-2-carboxylic acid (6.00 g). Yield=43%; 1H NMR (MeOD-D4, 90 MHz) δ 7.30 (s, 1H), 6.76-7.09 (m, 5H), 6.71 (s, 1H), 4.93 (d, J=8.4 Hz, 2H) and 4.65 (s, 2H); MS m/z 328 [M+1]+. (b) 5-(Benzyloxy)-4-oxo-1-(2,2,2-trifluoroethyl)-1,4-dihydropyridine-2-carboxylic acid (4.70 g, 14.4 mmol) was mixed with DMF (25 mL) and heated to 130° C. (bath temperature) for 3 hours. The mixture was concentrated under reduced pressure using a rotary evaporator and the residue was mixed with ethyl acetate (50 mL). It was then stirred for 2 hours at room temperature and filtered. The filtrate was concentrated to give 3-(benzyloxy)-1-(2,2,2-trifluoroethyl)pyridin-4(1H)-one (3.58 g). Yield=69%; 1H NMR (DMSO-D6, 400 MHz) δ (ppm) 7.57-7.84 (m, 2H), 7.22-7.57 (m, 5H), 6.25 (br. s, 1H) and 4.69-5.28 (m, 4H); MS m/z 284 [M+1]+. (c) 3-(Benzyloxy)-1-(2,2,2-trifluoroethyl)pyridin-4(1H)-one (1.2 g, 4.2 mmol) was mixed with 10% Palladium on charcoal (wet, 0.12 g) in ethanol (70 mL). The resulting mixture was hydrogenated at 15 psi of hydrogen pressure for 1.5 hours. Palladium was removed by filtration through a layer of Celite™ and the Celite™ cake was washed with methanol (5 mL×3). The filtrate was evaporated to give 3-hydroxy-1-(2,2,2-trifluoroethyl)pyridin-4(1H)-one (0.78 g) as white solid. Yield=95%; 1H NMR (DMSO-D6, 400 MHz) δ (ppm) 7.60 (d, J=7.1 Hz, 1H), 7.46 (s, 1H), 6.23 (d, J=7.1 Hz, 1H) and 4.80-5.00 (m, 2H); MS m/z 194 [M+1]+.

Provenance & Evidence