Phenylacetylene → 1,3-Bis(2,4,6-trimethylphenyl)-4-phenyl-1H-1,2,3-triazolium hexafluorophosphate

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Reaction Steps

To a stirred suspension of triazene 8b (845 mg, 3 mmol) and phenylacetylene 9a (660 μL, 6 mmol) in dry dichloromethane (20 mL) in the dark at −78° C. is added tert-butyl hypochlorite (500 μL, 4.4 mmol), upon which the mixture instantly darkens. The mixture is stirred overnight as it is slowly allowed to warm to room temperature. The contents are then filtered, and the solid residue is washed with dichloromethane. The filtrate is collected, and volatiles are evaporated under reduced pressure. The crude solid is redissolved in acetone (20 mL), to which is then added potassium hexafluorophosphate (750 mg, 4 mmol). The mixture is stirred at room temperature for ca. 1 hour, filtered, and the solid residue is washed with dichloromethane. The collected filtrate is evaporated under reduced pressure. Diethyl ether is then added, and the mixture is vigorously triturated for ca. 1 hour, with occasional scratching of the glass surfaces to ensure efficient mixing. Filtration and washing with copious quantities of diethyl ether afford, after drying under vacuum, triazolium salt 10ba as an off-white solid (1.42 g, 89%). Analytical samples were obtained after recrystallization by vapor diffusion of diethyl ether in an acetonitrile solution of 10ba. 1H-NMR (CD3CN, 300 MHz): δ=9.03 (s, 1H), 7.61 (tt, J=7.2, 1.5 Hz, 1H), 7.53-7.43 (m, 4H), 7.24 (s, 2H), 7.20 (s, 2H), 2.42 (s, 3H), 2.39 (s, 3H), 2.21 (s, 6H), 2.04 (s, 6H). 13C-NMR (CD3CN, 75 MHz): δ=145.9, 144.7, 144.4, 136.0, 135.6, 133.5, 132.5, 131.3, 131.0, 130.8, 129.5, 122.9, 21.4, 17.7, 17.6. HR-MS (ESI): Calcd. for C26H28N3 [M+]: 382.2278. found 382.2288.

Provenance & Evidence