Simple, novel, and efficient synthesis of ethyl 2-(2-(1H-indol-3-yl)benzo[d]thiazol-3(2H)-yl)-2-cyanoacetate or acetate via a three-component reaction

Ethyl 2-(2-(1 H-indol-3-yl)benzo[ d]thiazol-3(2 H)-yl)-2-cyanoacetate or acetate 6a–f as a series of novel compounds were synthesized from the reactions of benzothiazole, 2-methylbenzothiazole, or 2,5-dimethylbenzothiazole and ethyl bromocyanoacetate with indole derivatives. The reactions proceeded in acetone as a solvent under reflux for 5 h in good yields. The structures of new compounds were confirmed by 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, infrared, elemental analyses, and mass spectroscopy.