1,1'-Carbonyldiimidazole → HCID 69236140, compound

Participants

Reaction Steps

A stirred solution of 6-(trifluoromethoxy)-2,3,4,9-tetrahydro-1H-carbazole-3-carboxylic acid of Step 2 (1.722 g, 5.75 mmol) in anhydrous tetrahydrofuran (37 mL) was treated under nitrogen with carbonyldiimidazole (1.37 g, 8.61 mmol). The yellow solution was stirred at room temperature for 5 hours and then anhydrous ammonia was bubbled through the solution for 30 minutes. The suspension was diluted with ethyl acetate and the organic phase was washed with 1:1 water/saturated aqueous sodium bicarbonate and 1:1 water/brine. The extracts were dried over anhydrous magnesium sulfate and evaporated to dryness to yield a pale yellow glass. The residue was purified by chromatography on silica gel Merck-60 using a 1% to 3% gradient of methanol in dichloromethane to provide the title compound (1.33 g, 77%) as an off white solid, m.p. 177-178° C. MS [(+)ES, m/z]: 299 [M+H]+. HRMS [(+)ESI, m/z]: 299.1004 [M+H]+. Calc'd for C14H14F3N2O2: 299.1007. HPLC: Chromolith Monolith column, 0.46×10 cm, gradient of acetonitrile in water (0.01% TFA), 4 mL/min, detection at 254 nm; Rt 1.8 min.

Provenance & Evidence