Quick synthesis of isatin-derived knoevenagel adducts using only eco-friendly solvent

Abstract A variety of knoevenagel compounds from isatin were synthesized using an eco-friendly methodology. It was used only the binary solvent ethanol: water (3:7 v/v) without the presence of metal catalyst what enabled the reaction between different isatins with malononitrile in a quick reaction time of 2–5 min and isolated yields 80–96%. When cyanoesters were used as methylene actives, the reactions were longer and the knoenevagel products were obtained 79–92% isolated yields.