Synthesis and Analgesic Activity of N,N′-(Ethane-1,2-diyl)bis(spiroazetidin-2ones) Containing Cyclobutane, Cyclopentane or Cyclohexane Fragments

It was found that the Reformatsky reagents, obtained from methyl-1-bromocyclobutane-, 1-bromocyclopentane-, and 1-bromocyclohexanecarboxylates and zinc, react with diimines, derived from ethylenediamine and aromatic aldehydes, in a 2 : 1 molar ratio to form the corresponding bis(spiroazetidin-2-ones). The structure of the obtained compounds was confirmed by single crystal X-ray diffraction analysis. The in vivo analgesic activity of the synthesized compounds was assessed and shown to have pronounced effects, which exceeded those of the reference drug (sodium metamizole).