ChemInform Abstract: Reactions with 4-(Cyanoacetyl)phenazone: Synthesis of Novel Thiazole, Hydrazinopyrazole and Pyrazolo(5,1-c)(1.2.4)triazine Derivatives.

ChemInform Abstract

4-(Cyanoacetyl)phenazone (I) reacts with mercaptoacetic acid (II) to give the hydroxythiazole (III). Coupling of (III) with the diazonium salts (IV) yields the monosubstituted arylazo derivatives (V). When (III) is heated with phenylhydrazine, the cyclization product (VI) is formed. Reaction of (III) with the aromatic aldehydes (VII) gives (VIII). The pyrazolotriazine derivative (XI) is obtained from the thiazole (X) and the diazonium salt (IX).