Synthesis and Reactivity of Enaminones: Synthesis of Some 1,3,4‐Thiadiazole Linked to Pyrazole,Pyridine, Benzimidazolopyrimidine,Pyrazolopyrimidine, Pyrazolotriazine and Triazolotriazine Derivatives

1,3,4‐Thiadiazole‐enaminone ( 6 ) was synthesized via reaction of the benzamide ( 5 ) with DMF‐DMA. The simple thiadiazole‐enaminone ( 6 ) was used as a synthetic precursor for the synthesis of a wide variety of new heterocyclic compounds, including the 5‐substituted‐1,3,4‐thiadiazole derivatives ( 7 ), ( 8 ), ( 16 ), ( 17 ) and ( 18 ), which were obtained via reactions of ( 6 ) with nitrogen nucleophiles. Also, reactions of enaminone ( 6 ) with carbon nucleophiles afforded the respective 1,3,4‐thiadiazoles ( 10a , 10b ). Diazotization of the benzamide ( 20 ) with the heteroaromatic amine salts gave the hydrazone derivatives ( 21 ) and ( 22 ). Cyclization of the latter hydrazones yielded the corresponding pyrazolotriazine and 1,2,4‐triazolotriazine derivatives ( 23 ) and ( 24 ), respectively. All newly synthesized compounds were elucidated by considering the data of both elemental and spectral analysis.