Boron trifluoride etherate → 1-(Oxan-2-yl)-4,5-diphenyl-1H-imidazole

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Reaction Steps

A mixture of 27 g (0.122 mole) 4,5-diphenylimidazole, 21 g (0.25 mole) dihydropyran, 250 ml ethyl acetate and 4.0 g BF3.Et2O was refluxed for five days. The nearly clear solution was diluted with ether and filtered to remove 0.6 g insoluble starting material. The ether filtrate was washed several times with 10% NaHCO3 then dried and evaporated. TLC showed starting material still present, so the crude product was chromatographed on 2 lb. SilicAR CC-7, eluting with toluene containing 20 to 40% ethyl acetate. The pure 4,5-diphenyl-1-(2-tetrahydropyranyl) imidazole thus obtained weighed 30.3 g (82%) and had mp 170°-171°.

Provenance & Evidence