Acetic Acid → Diethyl 3-ethyl-1,3-dihydro-2H-pyrrole-2,2-dicarboxylate

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Reaction Steps

Diethyl benzyloxycarbonylaminomalonate (11.5 g, 38 mM) was dissolved in dry ethanol (50 ml) and added to a solution of sodium (150 mg) in dry ethanol (10 ml). Pent-2-enal (3.2 g 38 mM) in ethanol (10 ml) was added dropwise to the stirred mixture and the solution stirred for 1 hr. A solution of acetic acid (0.29 ml) in ethanol (1 ml) was then added and the solution hydrogenated for 2 hrs at atmospheric pressure using palladium on carbon (5%) as catalyst. The catalyst was removed by filtration and the filtrate evaporated. The residue was dissolved in chloroform and the solution washed with brine containing a little sodium bicarbonate, dried (Na2SO4) and evaporated. Distillation of the residue at 15 mm Hg gave 4-ethyl-5,5-dicarboethoxy-2-pyrroline (5.65 g) as a colourless oil b.p. 115°-120° (15 mm Hg) I.R. 1715, 1610 cm-1.

Provenance & Evidence