Amidrazones and 2‐Acetylcyclopentanone in the Synthesis of Cyclopenta[e][1,3,4]Oxadiazepines

Amidrazones reacted with 2‐acetylcyclopentanone at room temperature to give cyclopentae ]‐1,3,4]oxadiazepines. The structure of the obtained products was proved by IR, mass, and NMR spectra and elemental analyses. Two‐dimensional NMR spectroscopy was used to differentiate between other possible isomers. The reaction mechanism is also discussed.