Improved Synthesis Of 3-substituted Indole Derivatives

The synthesis of bisindolylmethanes, mannich bases,β-indolylketones, was reviewed in recent years. The synthesis of 3-substituted indole derivatives were improved by different methods. The reaction of aldehydes and indoles was obtained on 68-98% yields at roomtemperature within 1-5 min with grinding, catalyzed was by silicotungstic acid. The significant features of this procedure include higher yield and environment friendly.The reaction of secondary amine, formaldehyde and indole or N-methylindole can be carried out in 69-98% yields in acetic acid aqueous solution with 20-290 min at 35 oC under ultrasound irradiation.Camphorsulfonic acid catalyzed the Michael addition ofα,β-unsaturated ketones to indole under ultrasonic irradiation to afford the correspondingβ-indolylketones. This method provides several advantages such as operational simplicity and higher yield.