1,3-Dibromopropane → Diethyl 2,2-pyrrolidinedicarboxylate

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Reaction Steps

To a solution of sodium ethoxide (5.14 g) in absolute ethanol (75 mL) at 0° C. under a nitrogen atmosphere, a solution of diethyl aminomalonate (hydrochloride salt, 8 g) in absolute ethanol (75 mL) was slowly added. A yellow suspension was obtained at the end of the addition. 1,3-dibromo propane (7.7 mL) was then added and the resulting mixture was stirred at reflux temperature for 5 hours. The mixture was allowed to cool down to rt, then ethanol was removed in vacuo to give a yellow solid. This was dissolved in HCl (1M solution, 20 mL) and then washed with ethyl ether (2×50 mL). Phases were separated and the aqueous phase was brought to pH=9 by adding NaOH (1M solution). It was then extracted with ethyl ether (3×50 mL) and washed with brine (20 mL). The organic phase was dried and concentrated in vacuo to give the desired compound (2.35 g) as yellow oil.

Provenance & Evidence