NEW FINDINGS ON THE VILSMEIER-HAACK APPROACH TO QUINOLINE DERIVATIVES

The presence of electron-releasing substituents on the aromatic ring o f anilides. although necessary for the Vilsmeier-Haack cyclization to quinolines to proceed efficiently, can cause failure of the expected c yclization. leading to (Z) N,N-dimethylformamidines through an alterna tive course. A similar behaviour is observed when pi-donor groups are introduced on the alpha position of the anilide, although in this case some cyclization to quinoline derivatives generally occurs.