Mixed Oxides as Highly Selective Catalysts for the Flash Pyrolysis of Phenacyl Benzotriazole: One-Pot Synthesis of Dibenzazepin-7-one

The one-pot synthesis of dibenzo­[<i>b</i>,<i>d</i>]­azepin-7-one (<b>3</b>) was selectively achieved from 1-phenacyl-1,2,3-benzotriazole (<b>1</b>) using the catalytic flash vacuum pyrolysis (cfvp) methodology. Catalysts with the scheelite structure ABO₄ (A = Ca²⁺, Sr²⁺, Ba²⁺ and B = Mo⁶⁺, W⁶⁺) and fergusonite BiVO₄ were explored in this new catalytic reaction. These oxides promoted high conversion of starting material at lower temperatures than those observed for noncatalytic reactions. The chemical nature of A and B cations in the scheelite structure showed a strong influence on the formation toward the desired azepinone. In addition, the catalyst’s morphology had a significant influence on the course of the cfvp reaction