Unusual impurity formation during the process development of Olsalazine sodium leads to a new efficient and economical synthesis of tricaine mesylate

An impurity formation during the nitro group reduction for the synthesis of Olsalazine Sodium API, which was later explored for the development of a short and efficient manufacturing process for tricaine mesylate is reported here. The highlight of the synthesis is, during the nitro group reduction, the deoxygenation occurs forming the core of tricaine and the leaving mesyloxy group serves as a counter anion furnishing the tricaine mesylate in one step. The reported process here circumvents the need for isolation of the free base and a separate salt formation step, thus it is more economical and efficient. The data that supports the findings of this study are available in the supplementary material of this article. Data S1: Copies of 1H and 13C NMR spectra for 5, 8, ethyl salicylate (only 1H NMR), 14, 15, and 1. 13C CP MAS spectrum of 8. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.