Synthesis of substituted indazole acetic acids by N−N bond forming reactions

Herein, we report on the discovery and development of novel cascade N−N bond forming reactions for the synthesis of rare indazole acetic acid scaffolds. This approach allows for convenient synthesis of three distinct indazole acetic acid derivatives (unsubstituted, hydroxy, and alkoxy) by heating 3-amino-3-(2-nitroaryl)propanoic acids with an appropriate nucleophile/solvent under basic conditions. The reaction tolerates a range of functional groups and electronic effects and, in total, 23 novel indazole acetic acids were synthesized and characterized. This work offers a valuable strategy for the synthesis of useful scaffolds for drug discovery programs.