Dimethylformamide → Ethyl-4-iodo-1H-pyrrole-2-carboxylic acid ethyl ester

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Reaction Steps

Under a nitrogen atmosphere to a solution of 2,2,2-trichloro-1 (4-iodo-1H-pyrrol-2-yl)ethanone (9 g, 26.6 mmol) in DMF (30 mL) was added Cs2CO3 (17.4 g, 53.2 mmol) and stirred for 10 minutes. To this was then added a solution of iodoethane (8.72 g, 55.86 mmol) in DMF (10 mL). The new mixture was stirred at room temperature for 20 hours. A worked up TLC sample indicated the reaction was complete. DMF was removed in vacuo and the residue was taken back in a mixture of saturated aqueous NH4Cl: H2O (1:1, 200 mL) solution and extracted with ether. The combined ether extracts were washed with 5% Na2S2O5, dried (MgSO4) and filtered. Evaporation and purification by flash chromatography (hexane/ethyl acetate 9.7/0.3) gave light yellow oil (7 g, 89% yield), 1H NMR (400 MHZ, CDCl3) δ 1.3 (t, 3H), 1.35 (t, 3H), 4.22 (q 2H), 4.3 (q, 2H), 6.85 (s, 1H), 7.0 (s, 1H), MS m/e (M)+ 293.

Provenance & Evidence