Selenium-catalyzed intramolecular atom- and redox-economical transformation of o-nitrotoluenes into anthranilic acids

Anthranilic acids (AAs) are significant basic chemicals used in pharmaceuticals, agrochemicals, dyes, fragrances, etc. Superfluous steps are always involved in obtaining AAs. Herein, we demonstrate a straightforward strategy to transform abundant o-nitrotoluenes into biologically and pharmaceutically significant AAs without any extra reductants, oxidants and protecting groups. Various sensitive groups, such as halogens, sulfide, aldehyde, pyridines, quinolines, etc., can be tolerated in this transformation. A hundred-gram-scale operation is realized efficiently with almost quantitative selenium recycling. Further mechanistic studies and DFT calculations disclosed the proposed atom-exchange processes and the key roles of the selenium species.

Automated summary

This study introduces a direct strategy to transform abundant o-nitrotoluenes into AAs without the need for additional reductants, oxidants, or protecting groups, while also tolerating various sensitive groups. The efficient hundred-gram-scale operation with almost quantitative selenium recycling was demonstrated through further mechanistic studies and DFT calculations.