Vapor pressures and sublimation enthalpies of novel bicyclic heterocycle derivatives

Abstract

The vapor pressures of five novel bicyclic heterocycle derivatives were measured over the temperature 341.15 to 396.15K using the transpiration method by means of an inert gas carrier. From these results the standard enthalpies and Gibbs free energies of sublimation at the temperature 298.15K were calculated. The effects of alkyl- and chloro-substitutions on changes in the thermodynamic functions have been investigated. Quantitative structure–property relationship on the basis HYBOT physico-chemical descriptors for biologically active compounds have been developed to predict the sublimation enthalpies and Gibbs free energies of the compounds studied.