SYNTHETIC APPROACHES TO 3,3′-BIINDOLYL AND 3,3′-BIINDAZOLYL DERIVATIVES

In this paper new syntheses of 3,3'-biindolyl and 3,3'-biindazolyl derivatives are described. Formation of 3,3'-biindolyl derivatives by oxidative coupling of N-acetylindole with TeCl4 gave a good yield, while attempt to use the same reaction conditions for synthesis of 3,3'-biindazolyl derivatives failed. However, conversion of 3-haloindazole derivatives to its trimethylstannane derivative, followed by palladium-catalyzed Stille cross-coupling reaction, resulted in formation of 3,3'-biindazolyl derivatives.