Trifluoroacetic acid → 2-methyl-4-(1-methyl-1H-pyrazol-4-yl)-1H-imidazol-1-amine, trifluoroacetate salt

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Reaction Steps

A solution of tert-butyl [2-methyl-4-(1-methyl-1H-pyrazol-4-yl)-1H-imidazol-1-yl]carbamate (8.0 g, 29 mmol) in methylene chloride (200 mL) and trifluoroacetic acid (40 mL) was stirred at room temperature for 2.5 hours. After removal of solvents in vacuo, the residue was stirred in 1:1 ethyl acetate/heptane for 18 hours. The resulting solid was isolated by filtration to provide the product as a white solid. Yield: 5.3 g, 18 mmol, 62%. The mother liquor was concentrated in vacuo, and the residue was stirred for 30 minutes in a 1:1:1 mixture of ethyl acetate/heptane/diethyl ether (50 mL); filtration provided additional product as a white solid. Combined yield: 7.8 g, 26.8 mmol, 92%. 1H NMR (400 MHz, DMSO-d6) δ 2.54 (s, 3H), 3.89 (s, 3H), 6.55 (br s, 2H), 7.65 (s, 1H), 7.85 (d, J=0.7 Hz, 1H), 8.11 (br s, 1H).

Provenance & Evidence