Synthesis of novel spirocyclopropylmalonates and barbiturates

Abstract

Alkylidenemalonates have been subjected to dichlorocyclopropanation to produce novel spiro-gem-dichlorocyclopropylmalonates in quantitative yields. The latter have been reacted with urea in the presence of sodium ethoxide to produce the corresponding barbiturates in 80–95% yields. The cleavage of the spiro-gem-dichlorocyclopropylmalonate carbocycle with ethanol with the aid of aluminum chloride has led to ethyl ethers, while carbocycle expansion with isobutyraldehyde has afforded polysubstituted tetrahydrofurans. The prepared compounds have been structurally characterized in detail by ¹H and ¹³C NMR spectroscopy.