Ethenamine, N,N-dimethyl-2-nitro- → (E)-5-Chloro-2-ethyl-3-(2-nitroethenyl)-1H-indole

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Reaction Steps

The indole 3 (5 mmol) was added to a stirred ice-cooled solution of 1-(dimethylamino)-2-nitroethylene (0.58 g, 5 mmol) in trifluoroacetic acid (5 mL). The mixture was stirred at room temperature under N2, for 0.5 h and then poured onto ice water. The aqueous solution was extracted with ethyl acetate, the combined organic layers were washed with a saturated NaHCO3 solution and then with water. After drying over Na2SO4, the solvent was evaporated under reduced pressure to give a crude orange solid which was suspended in a mixture of EtOAc-Et2O and filtered, or chromatographed on silica gel (cyclohexane/EtOAc, 1:1, as eluent).

Provenance & Evidence