Mechanochemical Fischer indolisation: an eco-friendly design for a timeless reaction

Abstract

We developed an environmentally friendly mechanochemical protocol to induce an effective Fischer indolisation to synthesize indoles and indolines taking advantage of oxalic acid and dimethylurea. The solvent-free procedure shows versatility and wide scope; it applies to a broad range of arylhydrazines and carbonyl compounds, leading to variously decorated indoles and indolenines. Upon suitable modification, the methodology can also allow preparing compounds of pharmaceutical interest.