Synthesis of hydrazones of strained polycyclic hydrocarbons, promising building blocks in organic chemistry.

Hydrazones are a broad class of organic compounds, and due to their high reactivity they can act as intermediates in organic synthesis or be used as independent substances in various fields of science and technology. Despite significant research in the field of hydrazone chemistry, we noticed that there is no information in the literature on the synthesis of hydrazones of various strained polycyclic hydrocarbons.

In this work, for the first time, the synthesis of unsubstituted hydrazones was carried out based on various strained polycyclic hydrocarbons, which are of interest as promising building blocks in organic chemistry and medicine. Polycyclic hydrocarbons result from the dimerization of norbornadiene with a wide range of unsaturated compounds under Diels-Alder reaction conditions. There are a larger number of norbornadiene dimers, so we chose three compounds as objects of study as the most frequently formed and with good yields under dimerization reaction conditions, namely exo-exo-4-exo-Acetoxypentacyclo[8.2.1.1^5,8.0^2,9.0^3,7] tetradecane, endo-endo-4-exo-Acetoxypentacyclo[8.2.1.1^5,8.0^2,9.0^3,7] tetradecane and Acetoxyhexacyclo[9.2.1.0^2,7.0^3,5.0^4,8.0^9,13]tetradecane. The synthesis of hydrazones includes several successive stages, according to which at the first stage acetates are formed by boiling in acetic acid of the starting polycyclic hydrocarbons. The second stage involves the saponification of esters to the corresponding alcohols under the action of an alcoholic solution of potassium hydroxide. The third and fourth stages involve the subsequent oxidation of alcohols and the introduction of a new functional group using excess hydrazine hydrate. As a result, the corresponding unsubstituted hydrazones from strained polycyclic hydrocarbons were obtained. The yield of final products was 85-90%.