BF3 etherate-mediated microwave-assisted facile synthesis of thiopyrano[2,3-b]indol-2-one

Abstract A facile synthesis of indole annulated 2 H -thiopyran-2-ones has been developed by condensation of indoline-2-thiones with acetoacetic esters in the presence of borontrifluoride etherate (BF 3 etherate) using microwave irradiation. This one-step operationally simple methodology leads to thiopyrano[2,3- b ]indol-2-ones in good yields.