Pyridine → HCID 89710890, compound

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 2-propanol (690 μL, 9.0 mmol) and pyridine (750 μL, 9.3 mmol) in dichloromethane (5 mL) at −78° C. is added trifluoromethanesulfonic anhydride (1.5 mL, 8.9 mmol). The resulting mixture is stirred at −78° C. for 30 min, and then stirred an additional 30 min as is allowed to slowly reach room temperature. Pentane (10 mL) is added to precipitate the pyridinium salt byproduct, and contents are transferred via filter cannula into a solution of 1,4-bis(2,4,6-trimethylphenyl)-1H-1,2,3-triazole (915 mg, 3 mmol) in dichloromethane (5 mL) at 78° C. The resulting mixture is stirred at −78° C. for 30 min, and then stirred an additional 30 min as is allowed to slowly reach room temperature. Solvents are then evaporated under reduced pressured until a total volume of ca. 5 mL is reached, and additional dichloromethane (5 mL) is added. The mixture is stirred at room temperature overnight, followed by an additional 3 hour at 50° C. Evaporation of the volatiles under reduced pressure affords a crude product that is purified by column chromatography on SiO2 using 98:2 to 90:10 dichloromethane:methanol (v/v) as the mobile phase, and then by reprecipitation from dichloromethane into an excess of diethyl ether to afford triazolium salt 1d as a white solid (902 mg, 60%). 1H-NMR (CD3CN, 300 MHz): δ=8.65 (s, 1H), 7.23 (s, 2H), 7.20 (s, 2H), 4.67 (sept, J=6.8 Hz, 1H), 2.41 (s, 3H), 2.40 (s, 3H), 2.14 (s, 6H), 2.13 (s, 6H), 1.61 (d, J=6.8 Hz, 6H). 13C-NMR (CDCl3, 75 MHz): δ=144.1, 143.7, 142.2, 139.5, 135.6, 133.2, 132.7, 131.6, 130.9, 130.2, 57.5, 22.7, 21.5, 21.4, 20.5, 17.5. HR-MS (ESI): Calcd. for C23H30N3 [M+]: 348.2434. found 348.2436. M.p.: 180-181° C.

Provenance & Evidence