Cyclic dibenzoylhydrazines reproducing the conformation of ecdysone agonists, RH-5849

We have investigated the biologically active conformation of the non-steroidal ecdysone agonist, 1-tert-butyl-1,2-dibenzoylhydrazine (RH-5849) by means of design, synthesis and conformational analysis of cyclic derivatives of RH-5849. Among the synthesized compounds, a 6-membered cyclic hydrazine bearing two benzoyl groups (5) exists in three conformational states in solution, and the major unsymmetrical conformer of 5 is similar to that of RH-5849 on the basis of 1H NMR and X-ray analyses. The 3,3-dimethyl derivative of 5 (10) exists as a single unsymmetrical conformer. Although there is conformational similarity of the cyclic derivatives with RH-5849, these compounds did not show any hormonal or insecticidal activity. The hydrogen bonding character of the amide N-H group of the dibenzoylhydrazine seems to play a critical role in the appearance of the biological activity.