Trifluoroacetic acid → 5-(2,3-dihydro-benzo[1,4]dioxin-5-ylmethyl)-1H-imidazole

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Reaction Steps

A solution of (2,3-dihydro-benzo[1,4]dioxin-5-yl)-(1-trityl-1H-imidazol-4-yl)-methanol (Intermediate A3) (1 g, 2.11 mmol) in dichloromethane (30 mL) was reacted with TFA:trifluoroacetic acid (5.3 mL, 68 mmol)) and triethylsilane (TES) (2.8 mL, 17 mmol) at rt for 24 h. The mixture was evaporated under reduced pressure and quenched with solid NaHCO3. This material was subjected to an aqueous work-up and the residue was purified by chromatography on silica gel with 5% NH3-MeOH:CH2Cl2 to yield 5-(2,3-dihydro-benzo[1,4]dioxin-5-ylmethyl)-1H-imidazole (Intermediate A4) 330 mg (72%).

Provenance & Evidence