Hydrochloric Acid → ethyl 3-amino-5-(furan-2-yl)-1H-pyrrole-2-carboxylate

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Reaction Steps

To a solution of 2-cyano-1-(2-furyl)vinyl 4-methylbenzenesulfonate (10.48 g) and diethyl aminomalonate hydrochloride (7.67 g) in a mixed solvent of ethanol (120 mL)-tetrahydrofuran (64 mL) was added dropwise a solution (36.9 mL) of 20% sodium ethoxide in ethanol under ice-cooling. After stirring at room temperature for 12 hrs, the reaction mixture was poured into ice water (350 mL) and adjusted to pH 7 with 1N hydrochloric acid. The organic solvent was evaporated under reduced pressure, and the residue was extracted with ethyl acetate (150 mL×3). The organic layers were combined, washed with saturated brine (100 mL), and dried over anhydrous magnesium sulfate. After concentration under reduced pressure, the residue was purified by silica gel column chromatography (eluent, hexane:methyl acetate=3:1→1:1) and the obtained solid was recrystallized from ethyl acetate-hexane to give the title compound (2.66 g).

Provenance & Evidence