In order to investigate the isomerization and conversion mechanism of the advantageous and widely used nonsteroidal anti-inflammatory medicine flurbiprofen, the hybrid density functional theory was applied. | A theoretical investigation of the flurbiprofen methyl ester isomerization as the main step in the photopreparation of anti-inflammatory medicine S -flurbiprofen A DFT study Current Chemistry Letters 9 2020 161 170 Contents lists available at GrowingScience Current Chemistry Letters homepage A theoretical investigation of the flurbiprofen methyl ester isomerization as the main step in the photopreparation of anti-inflammatory medicine S -flurbiprofen A DFT study Saba Hadidia Mohammadsaleh Norouzibazazb c and Farshad Shiria a Department of Inorganic Chemistry Faculty of Chemistry Razi University Kermanshah Iran b Nano Science and Technology Research Center Razi University Kermanshah Iran c Department of Organic Chemistry Faculty of Chemistry Razi University Kermanshah Iran CHRONICLE ABSTRACT Article history In order to investigate the isomerization and conversion mechanism of the advantageous and Received October 8 2019 widely used nonsteroidal anti-inflammatory medicine flurbiprofen the hybrid density Received in revised form functional theory was applied. According to the results the rearrangement reaction of R - November 21 2019 flurbiprofen to its S -enantiomer happens in a 1 3 -hydrogen shifts with inversion of Accepted February 18 2020 configuration at chiral center C14. From the calculated energies it can be understood that the Available online rate-limiting step in the flurbiprofen isomerization is the excitation of R -flurbiprofen methyl February 18 2020 ester in its initial form to the first excited singlet state S1 at λ nm. we studied this Keywords process by scanning the C14-H17 distance for the excited singlet to get more information about Flurbiprofen the process of isomerization occurring upon excitation. The results of calculations R S isomerization demonstrated that the isomerization process should pass through a 71 kcal mol barrier. The DFT calculation S -flurbiprofen methyl ester is more photostable than its related
