Hectogram-Scale Synthesis of Indobufen from Diludine-Triggered Metal-Free Cascade

Abstract In this study, indobufen was successfully synthesized from diludine-triggered metal-free cascade in good yield. This process includes esterification, reduction, reductive amination/condensation cascade, hydrolysis, and recrystallization. Additionally, the post-treatment procedure was greatly simplified, and indobufen can be obtained by simple recrystallization that complies with the pharmacopoeia standards. Moreover, this work will be used as a basis for further research into the efficient production of indobufen on an industrial scale.