Abstract
Treatment of ethyl plopiolate (I) with diethyl acetamidomalonate (II) gave cyclized product, 1-acetyl-2-oxo-5, 5-diethoxycarbonyl-3-pyrroline (III). Analogously, III was obtained from ethyl cis-β-chloroacrylate (VIII) and the same reagent in good yield. VIII was treated with ethyl acetamidocyanoacetate (XIII) and diethyl carbobenzyloxyaminomalonate (XIV) to afford cyclized products, 1-acetyl-2-oxo-5-cyano-5-ethoxycarbonyl-3-pyrroline (XVII) and 1-carbobenzyloxy-2-oxo-5, 5-diethoxycarbonyl-3-pyrroline (XVIII), respectively. On the other hand, the reactions of VIII with diethyl benzamidomalonate (XV) and diethyl trifluoroacetamidomalonate (XVI) afforded open chain products, diethyl 4-benzamido-4-ethoxycarbonylglutaconate (XIX) and diethyl 4-trifluoroacetamido-4-ethoxycarbonylglutaconate (XX), respectively.
