Hydrochloric Acid → Diethyl 1H-pyrrole-2,4-dicarboxylate

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Reaction Steps

A suspension of potassium hydride (0.53 g, 13.26 mmol) in MTBE (10 mL) was added to a stirred solution of ethyl 2-isocyanoacetate (1 g, 8.84 mmol) and ethyl propiolate (1 g, 10.19 mmol) in MTBE (10 mL). The resulting mixture was stirred at rt for 4 h. The solution was then acidified with 1N HCl to pH≦3. The organic layer was washed with sat. NaHCO3 solution (2 mL), brine (2 mL), dried (MgSO4), and concentrated to give a solid residue. Purification via flash chromatography (petroleum ether:EtOAc, 15:1 to 10:1) afforded diethyl 1H-pyrrole-2,4-dicarboxylate (0.7 g, 37%). 1H NMR (CDCl3, 300 MHz) δ9.75 (br, 1 H), 7.49 (s, 1 H), 7.24 (s, 1 H), 4.25 (m, 4 H), 1.29 (m, 6 H).

Provenance & Evidence