Computational Studies of Stability, Reactivity and Degradation Properties of Ephedrine; a Stimulant and Precursor of Illicit Drugs

Some of the most important properties of ephedrine (EPH) molecule, related to its stability, reactivity and degradation have been computationally addressed in this work. The study has been performed based on the combination of classical and quantum-mechanical calculations to yield the lowest energy conformer. Furthermore, the most important intramolecular noncovalent interactions have been identified and their influence on the structural features have been analyzed. Energy and distribution of the frontier molecular orbitals have been analyzed in order to address the stability and charge transfer properties. The average local ionization energy descriptor has been used in order to identify the molecular sites that are sensitive towards the electrophilic attacks. Bond dissociation energies for hydrogen abstraction have been calculated in order to identify the sites of EPH sensitive towards the autoxidation mechanism. Interactions of EPH have been also investigated using the molecular dynamics simulations and calculations of radial distribution functions.