One-pot, three-component synthesis of spiro-[1,8]-naphthyridine derivatives as well as heterocyclic [3.3.3]-propellanes

An efficient, one-pot, base- and catalyst-free three-component pathway is described for the synthesis of novel spiro-[1,8]-naphthyridine derivatives by the condensation reaction between acenaphthenequinone/ninhydrin, malononitrile dimer, and enaminones in ethanol at reflux conditions. In addition, five new propellane derivatives were also synthesized via the same protocol when malono derivatives was used instead of enaminones. All the products were precipitated in the reaction medium and no additional operation was required for their purification except that, in some cases, recrystallization was used. Identification of products was done by the recorded of their 1H and 13C NMR, FT‒IR spectra and elemental analysis as well as melting points. [Display omitted]