Nanoscopy

The in vitro mechanism of ring opening of leflunomide resulting in formation of a metabolite A771726 has been studied by time series surface enhanced Raman spectra using NaOH buffer at pH ~10. The decomposition of leflunomide into A771726 through N-O bond cleavage was identified by the Raman signature of C≡N bond of A771726. The experimental results have been correlated with theory by transition state calculations of the reaction using different basic catalysts; OH-, formate and formate +water and water alone. The reaction barrier energy is found to be lowest with OH- as a catalyst.