Recent Update on Alkylation of Indole and Its Derivatives Using N‐Tosylhydrazone

Abstract

N‐Tosylhydrazones are valuable synthons in various organic transformations to achieve potent bioactive heterocycles. N‐tosylhydrazones largely serve as 1,3‐dipolar species for cycloaddition reactions, diazo precursors for carbene or carbenoid reactions, and alternatives to parent carbonyl compounds. On the other hand, indole derivatives exhibit wide range of pharmacological and therapeutic activities including anticancer, antiviral, antimalarial, antiasthmatic, antibacterial and anti‐inflammatory. This review mainly highlights the recent developments in the synthetic usefulness of N‐tosylhydrazones derived from indole‐carboxaldehydes and other carbonyl compounds. Moreover, the synthetic potential, scope, limitations, and mechanism of these transformations have also been discussed.