Enaminone Incorporating a Dibromobenzofuran Moiety: Versatile Precursor for Novel Azines and Azolotriazines

2‐Acetyl‐5,7‐dibromobenzo[ b ]furan ( 1 ) reacted with dimethylformamide‐dimethylacetal to give the corresponding ( E )‐enaminone 3 which coupled with aromatic diazonium chloride to afford the corresponding key intermediates 3‐oxo‐2‐(2‐arylhydrazono)propanals 6a , b . Compounds 6a , b were used to prepare novel 3‐imino‐2,3‐dihydropyridazines 10a , b and 6‐phenylazopyrido[2,3‐ d ]pyrimidin‐4(1 H )‐one derivatives 15a , b through their reaction with acetonitrile derivatives 8a , b and 6‐aminopyrimidin‐4(1 H )‐one 13 , respectively. On the other hand, the enaminone 3 was taken as a synthetic precursor to synthesize novel pyrazolo[5,1‐ c ][1,2,4]triazines 21a – c , [1,2,4]triazolo[3,4‐ c ][1,2,4]triazines 25 and benzimidazo[2,1‐ c ][1,2,4]triazine 29 containing 5,7‐dibromobenzofuran‐2‐oyl moiety via its coupling with the appropriate diazonium salts of a variety of hetero‐armomatic amines in a facile one‐step route.