Synthese von 4‐Aminocinnolinen aus (Arylhydrazono)(cyan)‐essigsäurederivaten

Synthesis of 4‐Aminocinnolines from (Arylhydrazono)(cyano)acetic Acid Derivatives The intramolecular Friedel‐Crafts reaction of (arylhydrazono)(cyano)acetamides and ‐malono‐nitriles 1 yields the 4‐amino‐3‐cinnolinecarboxylic acid derivatives 2. Toluene as solvent takes part in the reaction of 1d and e and forms the 4‐amino‐3‐cinnolyl p‐tolyl ketones 3. Ethyl (phenylhydrazono)(cyano)acetate reacts in the presence of AlCl3 to yield the 4‐hydroxy‐3‐cinnolinecarbonitrile (4). The pyrimido[5,4‐c]cinnolinone 6, the 4‐amino‐3‐cinnolinecarboxylic acid 2g, and its thioamide 2h can be obtained from 2.