Conversion of Isatins to Tryptanthrins, Heterocycles Endowed with a Myriad of Bioactivities: Conversion of Isatins to Tryptanthrins, Heterocycles Endowed with a Myriad of Bioactivities

The numerous bioactivities exhibited by tryptanthrins led chemists to develop synthetic approaches towards this important scaffold. In particular, conversion of isatins into tryptanthrins has been the subject of several studies. In this context, by using iodine and potassium hydroxide at room temperature, we have discovered a simple way to convert isatin and seven of its 5-substituted derivatives (Bu, F, Cl, Br, I, OMe and OCF 3 ) into the corresponding tryptanthrins. Furthermore, a mechanism was proposed to explain this original reactivity. Finally, we evaluated the antibacterial, antifungal, antioxidant and cytotoxic properties of the synthesized tryptanthrins. The unprecedented inhibition of human 20S constitutive proteasome was finally evaluated.