Synthesis of New Furo-Imidazo[3.3.3]propellanes

A new class of compounds, namely furo-imidazo-[3.3.3]propellanes can be synthesized by reaction of (1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile with N-substituted (2-picolinoyl-, thiophene-2- carbonyl)hydrazinecarbo-thioamides 1a-f. 2,5-Disubstituted-2,3,4-oxadiazoles were also separated from this reaction as a minor product. The structures of products have been confirmed by using IR, NMR, mass spectrometry and single crystal X-ray analyses. A mechanism for the formation of the products is presented.