Affiliation:
1. Ufa Institute of Chemistry of the Ufa Federal Research Centre of the Russian Academy of Sciences Ufa Russia
2. N.N.Vorozhtzov Novosibirsk Institute of Organic Chemistry SB RAS Novosibirsk Russia
Abstract
AbstractFirst case of regiospecific formation of indole fused with a triterpene scaffold is observed. Starting from 3‐oxo‐24‐nor‐allobetulin Fischer reaction with phenylhydrazine under the influence of weak acid catalyst led to 3H‐indole (indolenine) 4. This process was accompanied by a change in the configuration of the methyl group at C‐4 that was confirmed by x‐ray diffraction method. On the other hand, 3,2‐indole 5 was synthesized under the influence of strong acid catalyst (using phenylhydrazine hydrochloride in AcOH acid or phenylhydrazine in MeOH with a few drops of HCl).