Structure investigation of sertraline drug and its iodine product using mass spectrometry, thermal analyses and MO-calculations

Abstract

Sertraline (C 17H 17Cl 2N) as an antidepressant drug was investigated using thermal analysis (TA) measurements (TG/DTG and DTA) in comparison with electron impact (EI) mass spectral (MS) fragmentation at 70 eV. Semi-empirical MO-calculations, using PM3 procedure, has been carried out on neutral molecule and positively charged species. These calculations included bond length, bond order, bond strain, partial charge distribution and heats of formation (Δ H f). Also, in the present work sertraline-iodine product was prepared and its structure was investigated using elemental analyses, IR, 1H NMR, 13C NMR, MS and TA. It was also subjected to molecular orbital calculations (MOC) in order to confirm its fragmentation behavior by both MS and TA in comparison with the sertraline parent drug. In MS of sertraline the initial rupture occurred was CH 3NH 2 + fragment ion via H-rearrangement while in sertraline-iodine product the initial rupture was due to the loss of I + and/or HI + fragment ions followed by CH 2 NH + fragment ion loss. In thermal analyses (TA) the initial rupture in sertraline is due to the loss of C 6H 3Cl 2 followed by the loss of CH 3–NH forming tetraline molecule which thermally decomposed to give C 4H 8, C 6H 6 or the loss of H 2 forming naphthalene molecule which thermally sublimated. In sertraline-iodine product as a daughter the initial thermal rupture is due to successive loss of HI and CH 3NH followed by the loss of C 6H 5HI and HCl. Sertraline biological activity increases with the introduction of iodine into its skeleton. The activities of the drug and its daughter are mainly depend upon their fragmentation to give their metabolites in vivo systems, which are very similar to the identified fragments in both MS and TA. The importance of the present work is also due to the decision of the possible mechanism of fragmentation of the drug and its daughter and its confirmation by MOC.