Solid phase synthesis of functionalized indazoles using triazenes – scope and limitations

Abstract

Indazoles are important heterocycles as they are a substantial part in many drugs. In this study, we present a modular synthesis of highly substituted indazoles via a strategy on solid supports. The heterocyclic nitrogen atoms originate from diazonium salts, being cleaved from triazene containing resins. The scope and limitations of this process are explored, considering especially the competitive occurrence of triazines and the cleavage of hydrolyzed and traceless side products.