Unusual reactivity of β-(3-indolyl)-α,β-unsaturated ketones. 2-Acetylvinyl group removal by phenylhydrazine hydrochloride

The unusual removal of a 2-acetylvinyl group from the C3 position of an indole core during reaction with phenylhydrazine hydrochloride affording 3-unsubstituted 2-(hetero)arylindoles is described.