p-Toluenesulfonic acid monohydrate → 1-(4-Methanesulfonyl-phenyl)-2-thiophen-3-yl-4-trifluoromethyl-1H-imidazole

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Reaction Steps

A mixture of the 4,5-dihydro-imidazole of step 2 (1.5 g, 3.8 mmol) and p-toluenesulfonic acid monohydrate (0.30 g, 1.5 mmol) in toluene (250 ml) was heated to reflux for 40 hours. An additional p-toluenesulfonic acid monohydrate (0.15 g, 0.78 mmol) was added. The reaction mixture was heated to reflux for 18 hours. The reaction mixture was cooled and the solvent removed under reduced pressure. The crude mixture (3.5 g) was chromatographed on silica gel using ethyl acetate/toluene (55/45) to give pure 3-[1-[4-(methylsulfonyl)phenyl]-4-(trifluoromethyl)-1H-imidazol-2-yl]thiophene (0.90 g, 64%) as a white solid: mp 194°-197° C. Anal. Calc'd. for C15H11N2S2O2F3 : C, 48.38, H, 2.98, N, 7.52, S, 17.22. Found C, 48.74, H, 2.98, N, 7.56, S, 17.45.

Provenance & Evidence