Enthalpies of Formation of Five-Membered Nitrogen-Containing Heterocycles in the Condensed State

Background and Objective: For the alkyl and aryl derivatives of five-membered nitrogen-containing heterocyclic compounds a good correlation has been found between the experimental values of the enthalpy of formation of these compounds in the condensed state and the values calculated using semi-empirical quantum-chemical method PM3. Conclusion: A comparison of the proposed method with that of additive deposits and QSPR was made. Linear regression equation derived on the basis of correlation was used to predict the enthalpy of formation of compounds under consideration.